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-rw-r--r--arch/x86/kvm/mmu.c2
-rw-r--r--block/blk-mq-sysfs.c6
-rw-r--r--block/blk-mq.c18
-rw-r--r--block/blk-sysfs.c11
-rw-r--r--drivers/target/target_core_tpg.c3
-rw-r--r--fs/aio.c4
-rw-r--r--fs/btrfs/disk-io.c8
-rw-r--r--fs/btrfs/extent-tree.c2
-rw-r--r--fs/ext2/super.c6
-rw-r--r--fs/ext3/super.c6
-rw-r--r--fs/ext4/super.c14
-rw-r--r--fs/file_table.c2
-rw-r--r--fs/quota/dquot.c2
-rw-r--r--fs/super.c3
-rw-r--r--include/linux/blk-mq.h1
-rw-r--r--include/linux/flex_proportions.h5
-rw-r--r--include/linux/percpu-refcount.h122
-rw-r--r--include/linux/percpu.h13
-rw-r--r--include/linux/percpu_counter.h10
-rw-r--r--include/linux/proportions.h5
-rw-r--r--include/net/dst_ops.h2
-rw-r--r--include/net/inet_frag.h2
-rw-r--r--kernel/cgroup.c7
-rw-r--r--lib/flex_proportions.c8
-rw-r--r--lib/percpu-refcount.c305
-rw-r--r--lib/percpu_counter.c20
-rw-r--r--lib/proportions.c10
-rw-r--r--mm/backing-dev.c4
-rw-r--r--mm/mmap.c2
-rw-r--r--mm/nommu.c2
-rw-r--r--mm/page-writeback.c2
-rw-r--r--mm/percpu-km.c16
-rw-r--r--mm/percpu-vm.c162
-rw-r--r--mm/percpu.c526
-rw-r--r--mm/shmem.c2
-rw-r--r--net/dccp/proto.c2
-rw-r--r--net/ipv4/tcp.c4
-rw-r--r--net/ipv4/tcp_memcontrol.c2
-rw-r--r--net/sctp/protocol.c2
39 files changed, 879 insertions, 444 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 3201e93ebd0..ac1c4de3a48 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -4549,7 +4549,7 @@ int kvm_mmu_module_init(void)
if (!mmu_page_header_cache)
goto nomem;
- if (percpu_counter_init(&kvm_total_used_mmu_pages, 0))
+ if (percpu_counter_init(&kvm_total_used_mmu_pages, 0, GFP_KERNEL))
goto nomem;
register_shrinker(&mmu_shrinker);
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index ed521786755..371d8800b48 100644
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -402,6 +402,12 @@ static void blk_mq_sysfs_init(struct request_queue *q)
}
}
+/* see blk_register_queue() */
+void blk_mq_finish_init(struct request_queue *q)
+{
+ percpu_ref_switch_to_percpu(&q->mq_usage_counter);
+}
+
int blk_mq_register_disk(struct gendisk *disk)
{
struct device *dev = disk_to_dev(disk);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index df8e1e09dd1..38f4a165640 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -119,16 +119,7 @@ void blk_mq_freeze_queue(struct request_queue *q)
spin_unlock_irq(q->queue_lock);
if (freeze) {
- /*
- * XXX: Temporary kludge to work around SCSI blk-mq stall.
- * SCSI synchronously creates and destroys many queues
- * back-to-back during probe leading to lengthy stalls.
- * This will be fixed by keeping ->mq_usage_counter in
- * atomic mode until genhd registration, but, for now,
- * let's work around using expedited synchronization.
- */
- __percpu_ref_kill_expedited(&q->mq_usage_counter);
-
+ percpu_ref_kill(&q->mq_usage_counter);
blk_mq_run_queues(q, false);
}
wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->mq_usage_counter));
@@ -1804,7 +1795,12 @@ struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
if (!q)
goto err_hctxs;
- if (percpu_ref_init(&q->mq_usage_counter, blk_mq_usage_counter_release))
+ /*
+ * Init percpu_ref in atomic mode so that it's faster to shutdown.
+ * See blk_register_queue() for details.
+ */
+ if (percpu_ref_init(&q->mq_usage_counter, blk_mq_usage_counter_release,
+ PERCPU_REF_INIT_ATOMIC, GFP_KERNEL))
goto err_map;
setup_timer(&q->timeout, blk_mq_rq_timer, (unsigned long) q);
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 17f5c84ce7b..521ae9089c5 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -551,12 +551,19 @@ int blk_register_queue(struct gendisk *disk)
return -ENXIO;
/*
- * Initialization must be complete by now. Finish the initial
- * bypass from queue allocation.
+ * SCSI probing may synchronously create and destroy a lot of
+ * request_queues for non-existent devices. Shutting down a fully
+ * functional queue takes measureable wallclock time as RCU grace
+ * periods are involved. To avoid excessive latency in these
+ * cases, a request_queue starts out in a degraded mode which is
+ * faster to shut down and is made fully functional here as
+ * request_queues for non-existent devices never get registered.
*/
if (!blk_queue_init_done(q)) {
queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
blk_queue_bypass_end(q);
+ if (q->mq_ops)
+ blk_mq_finish_init(q);
}
ret = blk_trace_init_sysfs(dev);
diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index fddfae61222..be783f717f1 100644
--- a/drivers/target/target_core_tpg.c
+++ b/drivers/target/target_core_tpg.c
@@ -819,7 +819,8 @@ int core_tpg_add_lun(
{
int ret;
- ret = percpu_ref_init(&lun->lun_ref, core_tpg_lun_ref_release);
+ ret = percpu_ref_init(&lun->lun_ref, core_tpg_lun_ref_release, 0,
+ GFP_KERNEL);
if (ret < 0)
return ret;
diff --git a/fs/aio.c b/fs/aio.c
index 733750096b7..84a751005f5 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -661,10 +661,10 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
INIT_LIST_HEAD(&ctx->active_reqs);
- if (percpu_ref_init(&ctx->users, free_ioctx_users))
+ if (percpu_ref_init(&ctx->users, free_ioctx_users, 0, GFP_KERNEL))
goto err;
- if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs))
+ if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs, 0, GFP_KERNEL))
goto err;
ctx->cpu = alloc_percpu(struct kioctx_cpu);
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index a1d36e62179..d0d78dc0779 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1183,7 +1183,7 @@ static struct btrfs_subvolume_writers *btrfs_alloc_subvolume_writers(void)
if (!writers)
return ERR_PTR(-ENOMEM);
- ret = percpu_counter_init(&writers->counter, 0);
+ ret = percpu_counter_init(&writers->counter, 0, GFP_KERNEL);
if (ret < 0) {
kfree(writers);
return ERR_PTR(ret);
@@ -2188,7 +2188,7 @@ int open_ctree(struct super_block *sb,
goto fail_srcu;
}
- ret = percpu_counter_init(&fs_info->dirty_metadata_bytes, 0);
+ ret = percpu_counter_init(&fs_info->dirty_metadata_bytes, 0, GFP_KERNEL);
if (ret) {
err = ret;
goto fail_bdi;
@@ -2196,13 +2196,13 @@ int open_ctree(struct super_block *sb,
fs_info->dirty_metadata_batch = PAGE_CACHE_SIZE *
(1 + ilog2(nr_cpu_ids));
- ret = percpu_counter_init(&fs_info->delalloc_bytes, 0);
+ ret = percpu_counter_init(&fs_info->delalloc_bytes, 0, GFP_KERNEL);
if (ret) {
err = ret;
goto fail_dirty_metadata_bytes;
}
- ret = percpu_counter_init(&fs_info->bio_counter, 0);
+ ret = percpu_counter_init(&fs_info->bio_counter, 0, GFP_KERNEL);
if (ret) {
err = ret;
goto fail_delalloc_bytes;
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 3efe1c3877b..caaf015d6e4 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3494,7 +3494,7 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
if (!found)
return -ENOMEM;
- ret = percpu_counter_init(&found->total_bytes_pinned, 0);
+ ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL);
if (ret) {
kfree(found);
return ret;
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index b88edc05c23..170dc41e8bf 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -1067,14 +1067,14 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
err = percpu_counter_init(&sbi->s_freeblocks_counter,
- ext2_count_free_blocks(sb));
+ ext2_count_free_blocks(sb), GFP_KERNEL);
if (!err) {
err = percpu_counter_init(&sbi->s_freeinodes_counter,
- ext2_count_free_inodes(sb));
+ ext2_count_free_inodes(sb), GFP_KERNEL);
}
if (!err) {
err = percpu_counter_init(&sbi->s_dirs_counter,
- ext2_count_dirs(sb));
+ ext2_count_dirs(sb), GFP_KERNEL);
}
if (err) {
ext2_msg(sb, KERN_ERR, "error: insufficient memory");
diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index 622e8824902..bb0fdacad05 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -2039,14 +2039,14 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
goto failed_mount2;
}
err = percpu_counter_init(&sbi->s_freeblocks_counter,
- ext3_count_free_blocks(sb));
+ ext3_count_free_blocks(sb), GFP_KERNEL);
if (!err) {
err = percpu_counter_init(&sbi->s_freeinodes_counter,
- ext3_count_free_inodes(sb));
+ ext3_count_free_inodes(sb), GFP_KERNEL);
}
if (!err) {
err = percpu_counter_init(&sbi->s_dirs_counter,
- ext3_count_dirs(sb));
+ ext3_count_dirs(sb), GFP_KERNEL);
}
if (err) {
ext3_msg(sb, KERN_ERR, "error: insufficient memory");
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 0b28b36e791..05c159218bc 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3892,7 +3892,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
/* Register extent status tree shrinker */
ext4_es_register_shrinker(sbi);
- if ((err = percpu_counter_init(&sbi->s_extent_cache_cnt, 0)) != 0) {
+ err = percpu_counter_init(&sbi->s_extent_cache_cnt, 0, GFP_KERNEL);
+ if (err) {
ext4_msg(sb, KERN_ERR, "insufficient memory");
goto failed_mount3;
}
@@ -4106,17 +4107,20 @@ no_journal:
block = ext4_count_free_clusters(sb);
ext4_free_blocks_count_set(sbi->s_es,
EXT4_C2B(sbi, block));
- err = percpu_counter_init(&sbi->s_freeclusters_counter, block);
+ err = percpu_counter_init(&sbi->s_freeclusters_counter, block,
+ GFP_KERNEL);
if (!err) {
unsigned long freei = ext4_count_free_inodes(sb);
sbi->s_es->s_free_inodes_count = cpu_to_le32(freei);
- err = percpu_counter_init(&sbi->s_freeinodes_counter, freei);
+ err = percpu_counter_init(&sbi->s_freeinodes_counter, freei,
+ GFP_KERNEL);
}
if (!err)
err = percpu_counter_init(&sbi->s_dirs_counter,
- ext4_count_dirs(sb));
+ ext4_count_dirs(sb), GFP_KERNEL);
if (!err)
- err = percpu_counter_init(&sbi->s_dirtyclusters_counter, 0);
+ err = percpu_counter_init(&sbi->s_dirtyclusters_counter, 0,
+ GFP_KERNEL);
if (err) {
ext4_msg(sb, KERN_ERR, "insufficient memory");
goto failed_mount6;
diff --git a/fs/file_table.c b/fs/file_table.c
index 385bfd31512..0bab12b2046 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -331,5 +331,5 @@ void __init files_init(unsigned long mempages)
n = (mempages * (PAGE_SIZE / 1024)) / 10;
files_stat.max_files = max_t(unsigned long, n, NR_FILE);
- percpu_counter_init(&nr_files, 0);
+ percpu_counter_init(&nr_files, 0, GFP_KERNEL);
}
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index f2d0eee9d1f..8b663b2d956 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -2725,7 +2725,7 @@ static int __init dquot_init(void)
panic("Cannot create dquot hash table");
for (i = 0; i < _DQST_DQSTAT_LAST; i++) {
- ret = percpu_counter_init(&dqstats.counter[i], 0);
+ ret = percpu_counter_init(&dqstats.counter[i], 0, GFP_KERNEL);
if (ret)
panic("Cannot create dquot stat counters");
}
diff --git a/fs/super.c b/fs/super.c
index b9a214d2fe9..1b836107ace 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -175,7 +175,8 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags)
goto fail;
for (i = 0; i < SB_FREEZE_LEVELS; i++) {
- if (percpu_counter_init(&s->s_writers.counter[i], 0) < 0)
+ if (percpu_counter_init(&s->s_writers.counter[i], 0,
+ GFP_KERNEL) < 0)
goto fail;
lockdep_init_map(&s->s_writers.lock_map[i], sb_writers_name[i],
&type->s_writers_key[i], 0);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index a1e31f274fc..c13a0c09fae 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -140,6 +140,7 @@ enum {
};
struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *);
+void blk_mq_finish_init(struct request_queue *q);
int blk_mq_register_disk(struct gendisk *);
void blk_mq_unregister_disk(struct gendisk *);
diff --git a/include/linux/flex_proportions.h b/include/linux/flex_proportions.h
index 4ebc49fae39..0d348e011a6 100644
--- a/include/linux/flex_proportions.h
+++ b/include/linux/flex_proportions.h
@@ -10,6 +10,7 @@
#include <linux/percpu_counter.h>
#include <linux/spinlock.h>
#include <linux/seqlock.h>
+#include <linux/gfp.h>
/*
* When maximum proportion of some event type is specified, this is the
@@ -32,7 +33,7 @@ struct fprop_global {
seqcount_t sequence;
};
-int fprop_global_init(struct fprop_global *p);
+int fprop_global_init(struct fprop_global *p, gfp_t gfp);
void fprop_global_destroy(struct fprop_global *p);
bool fprop_new_period(struct fprop_global *p, int periods);
@@ -79,7 +80,7 @@ struct fprop_local_percpu {
raw_spinlock_t lock; /* Protect period and numerator */
};
-int fprop_local_init_percpu(struct fprop_local_percpu *pl);
+int fprop_local_init_percpu(struct fprop_local_percpu *pl, gfp_t gfp);
void fprop_local_destroy_percpu(struct fprop_local_percpu *pl);
void __fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl);
void __fprop_inc_percpu_max(struct fprop_global *p, struct fprop_local_percpu *pl,
diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h
index 68a64f11ce0..d5c89e0dd0e 100644
--- a/include/linux/percpu-refcount.h
+++ b/include/linux/percpu-refcount.h
@@ -13,7 +13,7 @@
*
* The refcount will have a range of 0 to ((1U << 31) - 1), i.e. one bit less
* than an atomic_t - this is because of the way shutdown works, see
- * percpu_ref_kill()/PCPU_COUNT_BIAS.
+ * percpu_ref_kill()/PERCPU_COUNT_BIAS.
*
* Before you call percpu_ref_kill(), percpu_ref_put() does not check for the
* refcount hitting 0 - it can't, if it was in percpu mode. percpu_ref_kill()
@@ -49,29 +49,60 @@
#include <linux/kernel.h>
#include <linux/percpu.h>
#include <linux/rcupdate.h>
+#include <linux/gfp.h>
struct percpu_ref;
typedef void (percpu_ref_func_t)(struct percpu_ref *);
+/* flags set in the lower bits of percpu_ref->percpu_count_ptr */
+enum {
+ __PERCPU_REF_ATOMIC = 1LU << 0, /* operating in atomic mode */
+ __PERCPU_REF_DEAD = 1LU << 1, /* (being) killed */
+ __PERCPU_REF_ATOMIC_DEAD = __PERCPU_REF_ATOMIC | __PERCPU_REF_DEAD,
+
+ __PERCPU_REF_FLAG_BITS = 2,
+};
+
+/* @flags for percpu_ref_init() */
+enum {
+ /*
+ * Start w/ ref == 1 in atomic mode. Can be switched to percpu
+ * operation using percpu_ref_switch_to_percpu(). If initialized
+ * with this flag, the ref will stay in atomic mode until
+ * percpu_ref_switch_to_percpu() is invoked on it.
+ */
+ PERCPU_REF_INIT_ATOMIC = 1 << 0,
+
+ /*
+ * Start dead w/ ref == 0 in atomic mode. Must be revived with
+ * percpu_ref_reinit() before used. Implies INIT_ATOMIC.
+ */
+ PERCPU_REF_INIT_DEAD = 1 << 1,
+};
+
struct percpu_ref {
- atomic_t count;
+ atomic_long_t count;
/*
* The low bit of the pointer indicates whether the ref is in percpu
* mode; if set, then get/put will manipulate the atomic_t.
*/
- unsigned long pcpu_count_ptr;
+ unsigned long percpu_count_ptr;
percpu_ref_func_t *release;
- percpu_ref_func_t *confirm_kill;
+ percpu_ref_func_t *confirm_switch;
+ bool force_atomic:1;
struct rcu_head rcu;
};
int __must_check percpu_ref_init(struct percpu_ref *ref,
- percpu_ref_func_t *release);
-void percpu_ref_reinit(struct percpu_ref *ref);
+ percpu_ref_func_t *release, unsigned int flags,
+ gfp_t gfp);
void percpu_ref_exit(struct percpu_ref *ref);
+void percpu_ref_switch_to_atomic(struct percpu_ref *ref,
+ percpu_ref_func_t *confirm_switch);
+void percpu_ref_switch_to_percpu(struct percpu_ref *ref);
void percpu_ref_kill_and_confirm(struct percpu_ref *ref,
percpu_ref_func_t *confirm_kill);
-void __percpu_ref_kill_expedited(struct percpu_ref *ref);
+void percpu_ref_reinit(struct percpu_ref *ref);
/**
* percpu_ref_kill - drop the initial ref
@@ -88,26 +119,24 @@ static inline void percpu_ref_kill(struct percpu_ref *ref)
return percpu_ref_kill_and_confirm(ref, NULL);
}
-#define PCPU_REF_DEAD 1
-
/*
* Internal helper. Don't use outside percpu-refcount proper. The
* function doesn't return the pointer and let the caller test it for NULL
* because doing so forces the compiler to generate two conditional
- * branches as it can't assume that @ref->pcpu_count is not NULL.
+ * branches as it can't assume that @ref->percpu_count is not NULL.
*/
-static inline bool __pcpu_ref_alive(struct percpu_ref *ref,
- unsigned __percpu **pcpu_countp)
+static inline bool __ref_is_percpu(struct percpu_ref *ref,
+ unsigned long __percpu **percpu_countp)
{
- unsigned long pcpu_ptr = ACCESS_ONCE(ref->pcpu_count_ptr);
+ unsigned long percpu_ptr = ACCESS_ONCE(ref->percpu_count_ptr);
/* paired with smp_store_release() in percpu_ref_reinit() */
smp_read_barrier_depends();
- if (unlikely(pcpu_ptr & PCPU_REF_DEAD))
+ if (unlikely(percpu_ptr & __PERCPU_REF_ATOMIC))
return false;
- *pcpu_countp = (unsigned __percpu *)pcpu_ptr;
+ *percpu_countp = (unsigned long __percpu *)percpu_ptr;
return true;
}
@@ -115,18 +144,20 @@ static inline bool __pcpu_ref_alive(struct percpu_ref *ref,
* percpu_ref_get - increment a percpu refcount
* @ref: percpu_ref to get
*
- * Analagous to atomic_inc().
- */
+ * Analagous to atomic_long_inc().
+ *
+ * This function is safe to call as long as @ref is between init and exit.
+ */
static inline void percpu_ref_get(struct percpu_ref *ref)
{
- unsigned __percpu *pcpu_count;
+ unsigned long __percpu *percpu_count;
rcu_read_lock_sched();
- if (__pcpu_ref_alive(ref, &pcpu_count))
- this_cpu_inc(*pcpu_count);
+ if (__ref_is_percpu(ref, &percpu_count))
+ this_cpu_inc(*percpu_count);
else
- atomic_inc(&ref->count);
+ atomic_long_inc(&ref->count);
rcu_read_unlock_sched();
}
@@ -138,20 +169,20 @@ static inline void percpu_ref_get(struct percpu_ref *ref)
* Increment a percpu refcount unless its count already reached zero.
* Returns %true on success; %false on failure.
*
- * The caller is responsible for ensuring that @ref stays accessible.
+ * This function is safe to call as long as @ref is between init and exit.
*/
static inline bool percpu_ref_tryget(struct percpu_ref *ref)
{
- unsigned __percpu *pcpu_count;
- int ret = false;
+ unsigned long __percpu *percpu_count;
+ int ret;
rcu_read_lock_sched();
- if (__pcpu_ref_alive(ref, &pcpu_count)) {
- this_cpu_inc(*pcpu_count);
+ if (__ref_is_percpu(ref, &percpu_count)) {
+ this_cpu_inc(*percpu_count);
ret = true;
} else {
- ret = atomic_inc_not_zero(&ref->count);
+ ret = atomic_long_inc_not_zero(&ref->count);
}
rcu_read_unlock_sched();
@@ -166,23 +197,26 @@ static inline bool percpu_ref_tryget(struct percpu_ref *ref)
* Increment a percpu refcount unless it has already been killed. Returns
* %true on success; %false on failure.
*
- * Completion of percpu_ref_kill() in itself doesn't guarantee that tryget
- * will fail. For such guarantee, percpu_ref_kill_and_confirm() should be
- * used. After the confirm_kill callback is invoked, it's guaranteed that
- * no new reference will be given out by percpu_ref_tryget().
+ * Completion of percpu_ref_kill() in itself doesn't guarantee that this
+ * function will fail. For such guarantee, percpu_ref_kill_and_confirm()
+ * should be used. After the confirm_kill callback is invoked, it's
+ * guaranteed that no new reference will be given out by
+ * percpu_ref_tryget_live().
*
- * The caller is responsible for ensuring that @ref stays accessible.
+ * This function is safe to call as long as @ref is between init and exit.
*/
static inline bool percpu_ref_tryget_live(struct percpu_ref *ref)
{
- unsigned __percpu *pcpu_count;
+ unsigned long __percpu *percpu_count;
int ret = false;
rcu_read_lock_sched();
- if (__pcpu_ref_alive(ref, &pcpu_count)) {
- this_cpu_inc(*pcpu_count);
+ if (__ref_is_percpu(ref, &percpu_count)) {
+ this_cpu_inc(*percpu_count);
ret = true;
+ } else if (!(ACCESS_ONCE(ref->percpu_count_ptr) & __PERCPU_REF_DEAD)) {
+ ret = atomic_long_inc_not_zero(&ref->count);
}
rcu_read_unlock_sched();
@@ -196,16 +230,18 @@ static inline bool percpu_ref_tryget_live(struct percpu_ref *ref)
*
* Decrement the refcount, and if 0, call the release function (which was passed
* to percpu_ref_init())
+ *
+ * This function is safe to call as long as @ref is between init and exit.
*/
static inline void percpu_ref_put(struct percpu_ref *ref)
{
- unsigned __percpu *pcpu_count;
+ unsigned long __percpu *percpu_count;
rcu_read_lock_sched();
- if (__pcpu_ref_alive(ref, &pcpu_count))
- this_cpu_dec(*pcpu_count);
- else if (unlikely(atomic_dec_and_test(&ref->count)))
+ if (__ref_is_percpu(ref, &percpu_count))
+ this_cpu_dec(*percpu_count);
+ else if (unlikely(atomic_long_dec_and_test(&ref->count)))
ref->release(ref);
rcu_read_unlock_sched();
@@ -216,14 +252,16 @@ static inline void percpu_ref_put(struct percpu_ref *ref)
* @ref: percpu_ref to test
*
* Returns %true if @ref reached zero.
+ *
+ * This function is safe to call as long as @ref is between init and exit.
*/
static inline bool percpu_ref_is_zero(struct percpu_ref *ref)
{
- unsigned __percpu *pcpu_count;
+ unsigned long __percpu *percpu_count;
- if (__pcpu_ref_alive(ref, &pcpu_count))
+ if (__ref_is_percpu(ref, &percpu_count))
return false;
- return !atomic_read(&ref->count);
+ return !atomic_long_read(&ref->count);
}
#endif
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index 6f61b61b799..a3aa63e4763 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -48,9 +48,9 @@
* intelligent way to determine this would be nice.
*/
#if BITS_PER_LONG > 32
-#define PERCPU_DYNAMIC_RESERVE (20 << 10)
+#define PERCPU_DYNAMIC_RESERVE (28 << 10)
#else
-#define PERCPU_DYNAMIC_RESERVE (12 << 10)
+#define PERCPU_DYNAMIC_RESERVE (20 << 10)
#endif
extern void *pcpu_base_addr;
@@ -122,11 +122,16 @@ extern void __init setup_per_cpu_areas(void);
#endif
extern void __init percpu_init_late(void);
+extern void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp);
extern void __percpu *__alloc_percpu(size_t size, size_t align);
extern void free_percpu(void __percpu *__pdata);
extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
-#define alloc_percpu(type) \
- (typeof(type) __percpu *)__alloc_percpu(sizeof(type), __alignof__(type))
+#define alloc_percpu_gfp(type, gfp) \
+ (typeof(type) __percpu *)__alloc_percpu_gfp(sizeof(type), \
+ __alignof__(type), gfp)
+#define alloc_percpu(type) \
+ (typeof(type) __percpu *)__alloc_percpu(sizeof(type), \
+ __alignof__(type))
#endif /* __LINUX_PERCPU_H */
diff --git a/include/linux/percpu_counter.h b/include/linux/percpu_counter.h
index d5dd4657c8d..50e50095c8d 100644
--- a/include/linux/percpu_counter.h
+++ b/include/linux/percpu_counter.h
@@ -12,6 +12,7 @@
#include <linux/threads.h>
#include <linux/percpu.h>
#include <linux/types.h>
+#include <linux/gfp.h>
#ifdef CONFIG_SMP
@@ -26,14 +27,14 @@ struct percpu_counter {
extern int percpu_counter_batch;
-int __percpu_counter_init(struct percpu_counter *fbc, s64 amount,
+int __percpu_counter_init(struct percpu_counter *fbc, s64 amount, gfp_t gfp,
struct lock_class_key *key);
-#define percpu_counter_init(fbc, value) \
+#define percpu_counter_init(fbc, value, gfp) \
({ \
static struct lock_class_key __key; \
\
- __percpu_counter_init(fbc, value, &__key); \
+ __percpu_counter_init(fbc, value, gfp, &__key); \
})
void percpu_counter_destroy(struct percpu_counter *fbc);
@@ -89,7 +90,8 @@ struct percpu_counter {
s64 count;
};
-static inline int percpu_counter_init(struct percpu_counter *fbc, s64 amount)
+static inline int percpu_counter_init(struct percpu_counter *fbc, s64 amount,
+ gfp_t gfp)
{
fbc->count = amount;
return 0;
diff --git a/include/linux/proportions.h b/include/linux/proportions.h
index 26a8a4ed9b0..00e8e8fa735 100644
--- a/include/linux/proportions.h
+++ b/include/linux/proportions.h
@@ -12,6 +12,7 @@
#include <linux/percpu_counter.h>
#include <linux/spinlock.h>
#include <linux/mutex.h>
+#include <linux/gfp.h>
struct prop_global {
/*
@@ -40,7 +41,7 @@ struct prop_descriptor {
struct mutex mutex; /* serialize the prop_global switch */
};
-int prop_descriptor_init(struct prop_descriptor *pd, int shift);
+int prop_descriptor_init(struct prop_descriptor *pd, int shift, gfp_t gfp);
void prop_change_shift(struct prop_descriptor *pd, int new_shift);
/*
@@ -61,7 +62,7 @@ struct prop_local_percpu {
raw_spinlock_t lock; /* protect the snapshot state */
};
-int prop_local_init_percpu(struct prop_local_percpu *pl);
+int prop_local_init_percpu(struct prop_local_percpu *pl, gfp_t gfp);
void prop_local_destroy_percpu(struct prop_local_percpu *pl);
void __prop_inc_percpu(struct prop_descriptor *pd, struct prop_local_percpu *pl);
void prop_fraction_percpu(struct prop_descriptor *pd, struct prop_local_percpu *pl,
diff --git a/include/net/dst_ops.h b/include/net/dst_ops.h
index 2f26dfb8450..1f99a1de0e4 100644
--- a/include/net/dst_ops.h
+++ b/include/net/dst_ops.h
@@ -63,7 +63,7 @@ static inline void dst_entries_add(struct dst_ops *dst, int val)
static inline int dst_entries_init(struct dst_ops *dst)
{
- return percpu_counter_init(&dst->pcpuc_entries, 0);
+ return percpu_counter_init(&dst->pcpuc_entries, 0, GFP_KERNEL);
}
static inline void dst_entries_destroy(struct dst_ops *dst)
diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h
index 65a8855e99f..8d1765577ac 100644
--- a/include/net/inet_frag.h
+++ b/include/net/inet_frag.h
@@ -151,7 +151,7 @@ static inline void add_frag_mem_limit(struct inet_frag_queue *q, int i)
static inline void init_frag_mem_limit(struct netns_frags *nf)
{
- percpu_counter_init(&nf->mem, 0);
+ percpu_counter_init(&nf->mem, 0, GFP_KERNEL);
}
static inline unsigned int sum_frag_mem_limit(struct netns_frags *nf)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index cab7dc4284d..136eceadeed 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1607,7 +1607,8 @@ static int cgroup_setup_root(struct cgroup_root *root, unsigned int ss_mask)
goto out;
root_cgrp->id = ret;
- ret = percpu_ref_init(&root_cgrp->self.refcnt, css_release);
+ ret = percpu_ref_init(&root_cgrp->self.refcnt, css_release, 0,
+ GFP_KERNEL);
if (ret)
goto out;
@@ -4482,7 +4483,7 @@ static int create_css(struct cgroup *cgrp, struct cgroup_subsys *ss,
init_and_link_css(css, ss, cgrp);
- err = percpu_ref_init(&css->refcnt, css_release);
+ err = percpu_ref_init(&css->refcnt, css_release, 0, GFP_KERNEL);
if (err)
goto err_free_css;
@@ -4555,7 +4556,7 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
goto out_unlock;
}
- ret = percpu_ref_init(&cgrp->self.refcnt, css_release);
+ ret = percpu_ref_init(&cgrp->self.refcnt, css_release, 0, GFP_KERNEL);
if (ret)
goto out_free_cgrp;
diff --git a/lib/flex_proportions.c b/lib/flex_proportions.c
index ebf3bac460b..8f25652f40d 100644
--- a/lib/flex_proportions.c
+++ b/lib/flex_proportions.c
@@ -34,13 +34,13 @@
*/
#include <linux/flex_proportions.h>
-int fprop_global_init(struct fprop_global *p)
+int fprop_global_init(struct fprop_global *p, gfp_t gfp)
{
int err;
p->period = 0;
/* Use 1 to avoid dealing with periods with 0 events... */
- err = percpu_counter_init(&p->events, 1);
+ err = percpu_counter_init(&p->events, 1, gfp);
if (err)
return err;
seqcount_init(&p->sequence);
@@ -168,11 +168,11 @@ void fprop_fraction_single(struct fprop_global *p,
*/
#define PROP_BATCH (8*(1+ilog2(nr_cpu_ids)))
-int fprop_local_init_percpu(struct fprop_local_percpu *pl)
+int fprop_local_init_percpu(struct fprop_local_percpu *pl, gfp_t gfp)
{
int err;
- err = percpu_counter_init(&pl->events, 0);
+ err = percpu_counter_init(&pl->events, 0, gfp);
if (err)
return err;
pl->period = 0;
diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c
index a89cf09a826..6111bcb2837 100644
--- a/lib/percpu-refcount.c
+++ b/lib/percpu-refcount.c
@@ -1,6 +1,8 @@
#define pr_fmt(fmt) "%s: " fmt "\n", __func__
#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
#include <linux/percpu-refcount.h>
/*
@@ -11,8 +13,8 @@
* percpu counters will all sum to the correct value
*
* (More precisely: because moduler arithmatic is commutative the sum of all the
- * pcpu_count vars will be equal to what it would have been if all the gets and
- * puts were done to a single integer, even if some of the percpu integers
+ * percpu_count vars will be equal to what it would have been if all the gets
+ * and puts were done to a single integer, even if some of the percpu integers
* overflow or underflow).
*
* The real trick to implementing percpu refcounts is shutdown. We can't detect
@@ -25,75 +27,64 @@
* works.
*
* Converting to non percpu mode is done with some RCUish stuff in
- * percpu_ref_kill. Additionally, we need a bias value so that the atomic_t
- * can't hit 0 before we've added up all the percpu refs.
+ * percpu_ref_kill. Additionally, we need a bias value so that the
+ * atomic_long_t can't hit 0 before we've added up all the percpu refs.
*/
-#define PCPU_COUNT_BIAS (1U << 31)
+#define PERCPU_COUNT_BIAS (1LU << (BITS_PER_LONG - 1))
-static unsigned __percpu *pcpu_count_ptr(struct percpu_ref *ref)
+static DECLARE_WAIT_QUEUE_HEAD(percpu_ref_switch_waitq);
+
+static unsigned long __percpu *percpu_count_ptr(struct percpu_ref *ref)
{
- return (unsigned __percpu *)(ref->pcpu_count_ptr & ~PCPU_REF_DEAD);
+ return (unsigned long __percpu *)
+ (ref->percpu_count_ptr & ~__PERCPU_REF_ATOMIC_DEAD);
}
/**
* percpu_ref_init - initialize a percpu refcount
* @ref: percpu_ref to initialize
* @release: function which will be called when refcount hits 0
+ * @flags: PERCPU_REF_INIT_* flags
+ * @gfp: allocation mask to use
*
- * Initializes the refcount in single atomic counter mode with a refcount of 1;
- * analagous to atomic_set(ref, 1).
+ * Initializes @ref. If @flags is zero, @ref starts in percpu mode with a
+ * refcount of 1; analagous to atomic_long_set(ref, 1). See the
+ * definitions of PERCPU_REF_INIT_* flags for flag behaviors.
*
* Note that @release must not sleep - it may potentially be called from RCU
* callback context by percpu_ref_kill().
*/
-int percpu_ref_init(struct percpu_ref *ref, percpu_ref_func_t *release)
+int percpu_ref_init(struct percpu_ref *ref, percpu_ref_func_t *release,
+ unsigned int flags, gfp_t gfp)
{
- atomic_set(&ref->count, 1 + PCPU_COUNT_BIAS);
+ size_t align = max_t(size_t, 1 << __PERCPU_REF_FLAG_BITS,
+ __alignof__(unsigned long));
+ unsigned long start_count = 0;
- ref->pcpu_count_ptr = (unsigned long)alloc_percpu(unsigned);
- if (!ref->pcpu_count_ptr)
+ ref->percpu_count_ptr = (unsigned long)
+ __alloc_percpu_gfp(sizeof(unsigned long), align, gfp);
+ if (!ref->percpu_count_ptr)
return -ENOMEM;
- ref->release = release;
- return 0;
-}
-EXPORT_SYMBOL_GPL(percpu_ref_init);
-
-/**
- * percpu_ref_reinit - re-initialize a percpu refcount
- * @ref: perpcu_ref to re-initialize
- *
- * Re-initialize @ref so that it's in the same state as when it finished
- * percpu_ref_init(). @ref must have been initialized successfully, killed
- * and reached 0 but not exited.
- *
- * Note that percpu_ref_tryget[_live]() are safe to perform on @ref while
- * this function is in progress.
- */
-void percpu_ref_reinit(struct percpu_ref *ref)
-{
- unsigned __percpu *pcpu_count = pcpu_count_ptr(ref);
- int cpu;
+ ref->force_atomic = flags & PERCPU_REF_INIT_ATOMIC;
- BUG_ON(!pcpu_count);
- WARN_ON(!percpu_ref_is_zero(ref));
+ if (flags & (PERCPU_REF_INIT_ATOMIC | PERCPU_REF_INIT_DEAD))
+ ref->percpu_count_ptr |= __PERCPU_REF_ATOMIC;
+ else
+ start_count += PERCPU_COUNT_BIAS;
- atomic_set(&ref->count, 1 + PCPU_COUNT_BIAS);
+ if (flags & PERCPU_REF_INIT_DEAD)
+ ref->percpu_count_ptr |= __PERCPU_REF_DEAD;
+ else
+ start_count++;
- /*
- * Restore per-cpu operation. smp_store_release() is paired with
- * smp_read_barrier_depends() in __pcpu_ref_alive() and guarantees
- * that the zeroing is visible to all percpu accesses which can see
- * the following PCPU_REF_DEAD clearing.
- */
- for_each_possible_cpu(cpu)
- *per_cpu_ptr(pcpu_count, cpu) = 0;
+ atomic_long_set(&ref->count, start_count);
- smp_store_release(&ref->pcpu_count_ptr,
- ref->pcpu_count_ptr & ~PCPU_REF_DEAD);
+ ref->release = release;
+ return 0;
}
-EXPORT_SYMBOL_GPL(percpu_ref_reinit);
+EXPORT_SYMBOL_GPL(percpu_ref_init);
/**
* percpu_ref_exit - undo percpu_ref_init()
@@ -107,26 +98,39 @@ EXPORT_SYMBOL_GPL(percpu_ref_reinit);
*/
void percpu_ref_exit(struct percpu_ref *ref)
{
- unsigned __percpu *pcpu_count = pcpu_count_ptr(ref);
+ unsigned long __percpu *percpu_count = percpu_count_ptr(ref);
- if (pcpu_count) {
- free_percpu(pcpu_count);
- ref->pcpu_count_ptr = PCPU_REF_DEAD;
+ if (percpu_count) {
+ free_percpu(percpu_count);
+ ref->percpu_count_ptr = __PERCPU_REF_ATOMIC_DEAD;
}
}
EXPORT_SYMBOL_GPL(percpu_ref_exit);
-static void percpu_ref_kill_rcu(struct rcu_head *rcu)
+static void percpu_ref_call_confirm_rcu(struct rcu_head *rcu)
+{
+ struct percpu_ref *ref = container_of(rcu, struct percpu_ref, rcu);
+
+ ref->confirm_switch(ref);
+ ref->confirm_switch = NULL;
+ wake_up_all(&percpu_ref_switch_waitq);
+
+ /* drop ref from percpu_ref_switch_to_atomic() */
+ percpu_ref_put(ref);
+}
+
+static void percpu_ref_switch_to_atomic_rcu(struct rcu_head *rcu)
{
struct percpu_ref *ref = container_of(rcu, struct percpu_ref, rcu);
- unsigned __percpu *pcpu_count = pcpu_count_ptr(ref);
- unsigned count = 0;
+ unsigned long __percpu *percpu_count = percpu_count_ptr(ref);
+ unsigned long count = 0;
int cpu;
for_each_possible_cpu(cpu)
- count += *per_cpu_ptr(pcpu_count, cpu);
+ count += *per_cpu_ptr(percpu_count, cpu);
- pr_debug("global %i pcpu %i", atomic_read(&ref->count), (int) count);
+ pr_debug("global %ld percpu %ld",
+ atomic_long_read(&ref->count), (long)count);
/*
* It's crucial that we sum the percpu counters _before_ adding the sum
@@ -140,21 +144,137 @@ static void percpu_ref_kill_rcu(struct rcu_head *rcu)
* reaching 0 before we add the percpu counts. But doing it at the same
* time is equivalent and saves us atomic operations:
*/
+ atomic_long_add((long)count - PERCPU_COUNT_BIAS, &ref->count);
+
+ WARN_ONCE(atomic_long_read(&ref->count) <= 0,
+ "percpu ref (%pf) <= 0 (%ld) after switching to atomic",
+ ref->release, atomic_long_read(&ref->count));
+
+ /* @ref is viewed as dead on all CPUs, send out switch confirmation */
+ percpu_ref_call_confirm_rcu(rcu);
+}
+
+static void percpu_ref_noop_confirm_switch(struct percpu_ref *ref)
+{
+}
+
+static void __percpu_ref_switch_to_atomic(struct percpu_ref *ref,
+ percpu_ref_func_t *confirm_switch)
+{
+ if (!(ref->percpu_count_ptr & __PERCPU_REF_ATOMIC)) {
+ /* switching from percpu to atomic */
+ ref->percpu_count_ptr |= __PERCPU_REF_ATOMIC;
+
+ /*
+ * Non-NULL ->confirm_switch is used to indicate that
+ * switching is in progress. Use noop one if unspecified.
+ */
+ WARN_ON_ONCE(ref->confirm_switch);
+ ref->confirm_switch =
+ confirm_switch ?: percpu_ref_noop_confirm_switch;
+
+ percpu_ref_get(ref); /* put after confirmation */
+ call_rcu_sched(&ref->rcu, percpu_ref_switch_to_atomic_rcu);
+ } else if (confirm_switch) {
+ /*
+ * Somebody already set ATOMIC. Switching may still be in
+ * progress. @confirm_switch must be invoked after the
+ * switching is complete and a full sched RCU grace period
+ * has passed. Wait synchronously for the previous
+ * switching and schedule @confirm_switch invocation.
+ */
+ wait_event(percpu_ref_switch_waitq, !ref->confirm_switch);
+ ref->confirm_switch = confirm_switch;
- atomic_add((int) count - PCPU_COUNT_BIAS, &ref->count);
+ percpu_ref_get(ref); /* put after confirmation */
+ call_rcu_sched(&ref->rcu, percpu_ref_call_confirm_rcu);
+ }
+}
+
+/**
+ * percpu_ref_switch_to_atomic - switch a percpu_ref to atomic mode
+ * @ref: percpu_ref to switch to atomic mode
+ * @confirm_switch: optional confirmation callback
+ *
+ * There's no reason to use this function for the usual reference counting.
+ * Use percpu_ref_kill[_and_confirm]().
+ *
+ * Schedule switching of @ref to atomic mode. All its percpu counts will
+ * be collected to the main atomic counter. On completion, when all CPUs
+ * are guaraneed to be in atomic mode, @confirm_switch, which may not
+ * block, is invoked. This function may be invoked concurrently with all
+ * the get/put operations and can safely be mixed with kill and reinit
+ * operations. Note that @ref will stay in atomic mode across kill/reinit
+ * cycles until percpu_ref_switch_to_percpu() is called.
+ *
+ * This function normally doesn't block and can be called from any context
+ * but it may block if @confirm_kill is specified and @ref is already in
+ * the process of switching to atomic mode. In such cases, @confirm_switch
+ * will be invoked after the switching is complete.
+ *
+ * Due to the way percpu_ref is implemented, @confirm_switch will be called
+ * after at least one full sched RCU grace period has passed but this is an
+ * implementation detail and must not be depended upon.
+ */
+void percpu_ref_switch_to_atomic(struct percpu_ref *ref,
+ percpu_ref_func_t *confirm_switch)
+{
+ ref->force_atomic = true;
+ __percpu_ref_switch_to_atomic(ref, confirm_switch);
+}
- WARN_ONCE(atomic_read(&ref->count) <= 0, "percpu ref <= 0 (%i)",
- atomic_read(&ref->count));
+static void __percpu_ref_switch_to_percpu(struct percpu_ref *ref)
+{
+ unsigned long __percpu *percpu_count = percpu_count_ptr(ref);
+ int cpu;
+
+ BUG_ON(!percpu_count);
- /* @ref is viewed as dead on all CPUs, send out kill confirmation */
- if (ref->confirm_kill)
- ref->confirm_kill(ref);
+ if (!(ref->percpu_count_ptr & __PERCPU_REF_ATOMIC))
+ return;
+
+ wait_event(percpu_ref_switch_waitq, !ref->confirm_switch);
+
+ atomic_long_add(PERCPU_COUNT_BIAS, &ref->count);
/*
- * Now we're in single atomic_t mode with a consistent refcount, so it's
- * safe to drop our initial ref:
+ * Restore per-cpu operation. smp_store_release() is paired with
+ * smp_read_barrier_depends() in __ref_is_percpu() and guarantees
+ * that the zeroing is visible to all percpu accesses which can see
+ * the following __PERCPU_REF_ATOMIC clearing.
*/
- percpu_ref_put(ref);
+ for_each_possible_cpu(cpu)
+ *per_cpu_ptr(percpu_count, cpu) = 0;
+
+ smp_store_release(&ref->percpu_count_ptr,
+ ref->percpu_count_ptr & ~__PERCPU_REF_ATOMIC);
+}
+
+/**
+ * percpu_ref_switch_to_percpu - switch a percpu_ref to percpu mode
+ * @ref: percpu_ref to switch to percpu mode
+ *
+ * There's no reason to use this function for the usual reference counting.
+ * To re-use an expired ref, use percpu_ref_reinit().
+ *
+ * Switch @ref to percpu mode. This function may be invoked concurrently
+ * with all the get/put operations and can safely be mixed with kill and
+ * reinit operations. This function reverses the sticky atomic state set
+ * by PERCPU_REF_INIT_ATOMIC or percpu_ref_switch_to_atomic(). If @ref is
+ * dying or dead, the actual switching takes place on the following
+ * percpu_ref_reinit().
+ *
+ * This function normally doesn't block and can be called from any context
+ * but it may block if @ref is in the process of switching to atomic mode
+ * by percpu_ref_switch_atomic().
+ */
+void percpu_ref_switch_to_percpu(struct percpu_ref *ref)
+{
+ ref->force_atomic = false;
+
+ /* a dying or dead ref can't be switched to percpu mode w/o reinit */
+ if (!(ref->percpu_count_ptr & __PERCPU_REF_DEAD))
+ __percpu_ref_switch_to_percpu(ref);
}
/**
@@ -164,39 +284,48 @@ static void percpu_ref_kill_rcu(struct rcu_head *rcu)
*
* Equivalent to percpu_ref_kill() but also schedules kill confirmation if
* @confirm_kill is not NULL. @confirm_kill, which may not block, will be
- * called after @ref is seen as dead from all CPUs - all further
- * invocations of percpu_ref_tryget() will fail. See percpu_ref_tryget()
- * for more details.
+ * called after @ref is seen as dead from all CPUs at which point all
+ * further invocations of percpu_ref_tryget_live() will fail. See
+ * percpu_ref_tryget_live() for details.
+ *
+ * This function normally doesn't block and can be called from any context
+ * but it may block if @confirm_kill is specified and @ref is in the
+ * process of switching to atomic mode by percpu_ref_switch_atomic().
*
- * Due to the way percpu_ref is implemented, @confirm_kill will be called
- * after at least one full RCU grace period has passed but this is an
- * implementation detail and callers must not depend on it.
+ * Due to the way percpu_ref is implemented, @confirm_switch will be called
+ * after at least one full sched RCU grace period has passed but this is an
+ * implementation detail and must not be depended upon.
*/
void percpu_ref_kill_and_confirm(struct percpu_ref *ref,
percpu_ref_func_t *confirm_kill)
{
- WARN_ONCE(ref->pcpu_count_ptr & PCPU_REF_DEAD,
- "percpu_ref_kill() called more than once!\n");
+ WARN_ONCE(ref->percpu_count_ptr & __PERCPU_REF_DEAD,
+ "%s called more than once on %pf!", __func__, ref->release);
- ref->pcpu_count_ptr |= PCPU_REF_DEAD;
- ref->confirm_kill = confirm_kill;
-
- call_rcu_sched(&ref->rcu, percpu_ref_kill_rcu);
+ ref->percpu_count_ptr |= __PERCPU_REF_DEAD;
+ __percpu_ref_switch_to_atomic(ref, confirm_kill);
+ percpu_ref_put(ref);
}
EXPORT_SYMBOL_GPL(percpu_ref_kill_and_confirm);
-/*
- * XXX: Temporary kludge to work around SCSI blk-mq stall. Used only by
- * block/blk-mq.c::blk_mq_freeze_queue(). Will be removed during v3.18
- * devel cycle. Do not use anywhere else.
+/**
+ * percpu_ref_reinit - re-initialize a percpu refcount
+ * @ref: perpcu_ref to re-initialize
+ *
+ * Re-initialize @ref so that it's in the same state as when it finished
+ * percpu_ref_init() ignoring %PERCPU_REF_INIT_DEAD. @ref must have been
+ * initialized successfully and reached 0 but not exited.
+ *
+ * Note that percpu_ref_tryget[_live]() are safe to perform on @ref while
+ * this function is in progress.
*/
-void __percpu_ref_kill_expedited(struct percpu_ref *ref)
+void percpu_ref_reinit(struct percpu_ref *ref)
{
- WARN_ONCE(ref->pcpu_count_ptr & PCPU_REF_DEAD,
- "percpu_ref_kill() called more than once on %pf!",
- ref->release);
+ WARN_ON_ONCE(!percpu_ref_is_zero(ref));
- ref->pcpu_count_ptr |= PCPU_REF_DEAD;
- synchronize_sched_expedited();
- percpu_ref_kill_rcu(&ref->rcu);
+ ref->percpu_count_ptr &= ~__PERCPU_REF_DEAD;
+ percpu_ref_get(ref);
+ if (!ref->force_atomic)
+ __percpu_ref_switch_to_percpu(ref);
}
+EXPORT_SYMBOL_GPL(percpu_ref_reinit);
diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index 7dd33577b90..48144cdae81 100644
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -112,13 +112,15 @@ s64 __percpu_counter_sum(struct percpu_counter *fbc)
}
EXPORT_SYMBOL(__percpu_counter_sum);
-int __percpu_counter_init(struct percpu_counter *fbc, s64 amount,
+int __percpu_counter_init(struct percpu_counter *fbc, s64 amount, gfp_t gfp,
struct lock_class_key *key)
{
+ unsigned long flags __maybe_unused;
+
raw_spin_lock_init(&fbc->lock);
lockdep_set_class(&fbc->lock, key);
fbc->count = amount;
- fbc->counters = alloc_percpu(s32);
+ fbc->counters = alloc_percpu_gfp(s32, gfp);
if (!fbc->counters)
return -ENOMEM;
@@ -126,9 +128,9 @@ int __percpu_counter_init(struct percpu_counter *fbc, s64 amount,
#ifdef CONFIG_HOTPLUG_CPU
INIT_LIST_HEAD(&fbc->list);
- spin_lock(&percpu_counters_lock);
+ spin_lock_irqsave(&percpu_counters_lock, flags);
list_add(&fbc->list, &percpu_counters);
- spin_unlock(&percpu_counters_lock);
+ spin_unlock_irqrestore(&percpu_counters_lock, flags);
#endif
return 0;
}
@@ -136,15 +138,17 @@ EXPORT_SYMBOL(__percpu_counter_init);
void percpu_counter_destroy(struct percpu_counter *fbc)
{
+ unsigned long flags __maybe_unused;
+
if (!fbc->counters)
return;
debug_percpu_counter_deactivate(fbc);
#ifdef CONFIG_HOTPLUG_CPU
- spin_lock(&percpu_counters_lock);
+ spin_lock_irqsave(&percpu_counters_lock, flags);
list_del(&fbc->list);
- spin_unlock(&percpu_counters_lock);
+ spin_unlock_irqrestore(&percpu_counters_lock, flags);
#endif
free_percpu(fbc->counters);
fbc->counters = NULL;
@@ -173,7 +177,7 @@ static int percpu_counter_hotcpu_callback(struct notifier_block *nb,
return NOTIFY_OK;
cpu = (unsigned long)hcpu;
- spin_lock(&percpu_counters_lock);
+ spin_lock_irq(&percpu_counters_lock);
list_for_each_entry(fbc, &percpu_counters, list) {
s32 *pcount;
unsigned long flags;
@@ -184,7 +188,7 @@ static int percpu_counter_hotcpu_callback(struct notifier_block *nb,
*pcount = 0;
raw_spin_unlock_irqrestore(&fbc->lock, flags);
}
- spin_unlock(&percpu_counters_lock);
+ spin_unlock_irq(&percpu_counters_lock);
#endif
return NOTIFY_OK;
}
diff --git a/lib/proportions.c b/lib/proportions.c
index 05df84801b5..6f724298f67 100644
--- a/lib/proportions.c
+++ b/lib/proportions.c
@@ -73,7 +73,7 @@
#include <linux/proportions.h>
#include <linux/rcupdate.h>
-int prop_descriptor_init(struct prop_descriptor *pd, int shift)
+int prop_descriptor_init(struct prop_descriptor *pd, int shift, gfp_t gfp)
{
int err;
@@ -83,11 +83,11 @@ int prop_descriptor_init(struct prop_descriptor *pd, int shift)
pd->index = 0;
pd->pg[0].shift = shift;
mutex_init(&pd->mutex);
- err = percpu_counter_init(&pd->pg[0].events, 0);
+ err = percpu_counter_init(&pd->pg[0].events, 0, gfp);
if (err)
goto out;
- err = percpu_counter_init(&pd->pg[1].events, 0);
+ err = percpu_counter_init(&pd->pg[1].events, 0, gfp);
if (err)
percpu_counter_destroy(&pd->pg[0].events);
@@ -188,12 +188,12 @@ prop_adjust_shift(int *pl_shift, unsigned long *pl_period, int new_shift)
#define PROP_BATCH (8*(1+ilog2(nr_cpu_ids)))
-int prop_local_init_percpu(struct prop_local_percpu *pl)
+int prop_local_init_percpu(struct prop_local_percpu *pl, gfp_t gfp)
{
raw_spin_lock_init(&pl->lock);
pl->shift = 0;
pl->period = 0;
- return percpu_counter_init(&pl->events, 0);
+ return percpu_counter_init(&pl->events, 0, gfp);
}
void prop_local_destroy_percpu(struct prop_local_percpu *pl)
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index b27714f1b40..12a992b6257 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -455,7 +455,7 @@ int bdi_init(struct backing_dev_info *bdi)
bdi_wb_init(&bdi->wb, bdi);
for (i = 0; i < NR_BDI_STAT_ITEMS; i++) {
- err = percpu_counter_init(&bdi->bdi_stat[i], 0);
+ err = percpu_counter_init(&bdi->bdi_stat[i], 0, GFP_KERNEL);
if (err)
goto err;
}
@@ -470,7 +470,7 @@ int bdi_init(struct backing_dev_info *bdi)
bdi->write_bandwidth = INIT_BW;
bdi->avg_write_bandwidth = INIT_BW;
- err = fprop_local_init_percpu(&bdi->completions);
+ err = fprop_local_init_percpu(&bdi->completions, GFP_KERNEL);
if (err) {
err:
diff --git a/mm/mmap.c b/mm/mmap.c
index 16d19b48e2a..93d28c7e542 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3202,7 +3202,7 @@ void __init mmap_init(void)
{
int ret;
- ret = percpu_counter_init(&vm_committed_as, 0);
+ ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
VM_BUG_ON(ret);
}
diff --git a/mm/nommu.c b/mm/nommu.c
index a881d9673c6..bd1808e194a 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -539,7 +539,7 @@ void __init mmap_init(void)
{
int ret;
- ret = percpu_counter_init(&vm_committed_as, 0);
+ ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
VM_BUG_ON(ret);
vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
}
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 35ca7102d42..ff24c9d8311 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1777,7 +1777,7 @@ void __init page_writeback_init(void)
writeback_set_ratelimit();
register_cpu_notifier(&ratelimit_nb);
- fprop_global_init(&writeout_completions);
+ fprop_global_init(&writeout_completions, GFP_KERNEL);
}
/**
diff --git a/mm/percpu-km.c b/mm/percpu-km.c
index 89633fefc6a..10e3d0b8a86 100644
--- a/mm/percpu-km.c
+++ b/mm/percpu-km.c
@@ -33,17 +33,14 @@
#include <linux/log2.h>
-static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
+static int pcpu_populate_chunk(struct pcpu_chunk *chunk,
+ int page_start, int page_end)
{
- unsigned int cpu;
-
- for_each_possible_cpu(cpu)
- memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
-
return 0;
}
-static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size)
+static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk,
+ int page_start, int page_end)
{
/* nada */
}
@@ -70,6 +67,11 @@ static struct pcpu_chunk *pcpu_create_chunk(void)
chunk->data = pages;
chunk->base_addr = page_address(pages) - pcpu_group_offsets[0];
+
+ spin_lock_irq(&pcpu_lock);
+ pcpu_chunk_populated(chunk, 0, nr_pages);
+ spin_unlock_irq(&pcpu_lock);
+
return chunk;
}
diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c
index 51108165f82..538998a137d 100644
--- a/mm/percpu-vm.c
+++ b/mm/percpu-vm.c
@@ -20,46 +20,25 @@ static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk,
}
/**
- * pcpu_get_pages_and_bitmap - get temp pages array and bitmap
+ * pcpu_get_pages - get temp pages array
* @chunk: chunk of interest
- * @bitmapp: output parameter for bitmap
- * @may_alloc: may allocate the array
*
- * Returns pointer to array of pointers to struct page and bitmap,
- * both of which can be indexed with pcpu_page_idx(). The returned
- * array is cleared to zero and *@bitmapp is copied from
- * @chunk->populated. Note that there is only one array and bitmap
- * and access exclusion is the caller's responsibility.
- *
- * CONTEXT:
- * pcpu_alloc_mutex and does GFP_KERNEL allocation if @may_alloc.
- * Otherwise, don't care.
+ * Returns pointer to array of pointers to struct page which can be indexed
+ * with pcpu_page_idx(). Note that there is only one array and accesses
+ * should be serialized by pcpu_alloc_mutex.
*
* RETURNS:
- * Pointer to temp pages array on success, NULL on failure.
+ * Pointer to temp pages array on success.
*/
-static struct page **pcpu_get_pages_and_bitmap(struct pcpu_chunk *chunk,
- unsigned long **bitmapp,
- bool may_alloc)
+static struct page **pcpu_get_pages(struct pcpu_chunk *chunk_alloc)
{
static struct page **pages;
- static unsigned long *bitmap;
size_t pages_size = pcpu_nr_units * pcpu_unit_pages * sizeof(pages[0]);
- size_t bitmap_size = BITS_TO_LONGS(pcpu_unit_pages) *
- sizeof(unsigned long);
-
- if (!pages || !bitmap) {
- if (may_alloc && !pages)
- pages = pcpu_mem_zalloc(pages_size);
- if (may_alloc && !bitmap)
- bitmap = pcpu_mem_zalloc(bitmap_size);
- if (!pages || !bitmap)
- return NULL;
- }
- bitmap_copy(bitmap, chunk->populated, pcpu_unit_pages);
+ lockdep_assert_held(&pcpu_alloc_mutex);
- *bitmapp = bitmap;
+ if (!pages)
+ pages = pcpu_mem_zalloc(pages_size);
return pages;
}
@@ -67,7 +46,6 @@ static struct page **pcpu_get_pages_and_bitmap(struct pcpu_chunk *chunk,
* pcpu_free_pages - free pages which were allocated for @chunk
* @chunk: chunk pages were allocated for
* @pages: array of pages to be freed, indexed by pcpu_page_idx()
- * @populated: populated bitmap
* @page_start: page index of the first page to be freed
* @page_end: page index of the last page to be freed + 1
*
@@ -75,8 +53,7 @@ static struct page **pcpu_get_pages_and_bitmap(struct pcpu_chunk *chunk,
* The pages were allocated for @chunk.
*/
static void pcpu_free_pages(struct pcpu_chunk *chunk,
- struct page **pages, unsigned long *populated,
- int page_start, int page_end)
+ struct page **pages, int page_start, int page_end)
{
unsigned int cpu;
int i;
@@ -95,7 +72,6 @@ static void pcpu_free_pages(struct pcpu_chunk *chunk,
* pcpu_alloc_pages - allocates pages for @chunk
* @chunk: target chunk
* @pages: array to put the allocated pages into, indexed by pcpu_page_idx()
- * @populated: populated bitmap
* @page_start: page index of the first page to be allocated
* @page_end: page index of the last page to be allocated + 1
*
@@ -104,8 +80,7 @@ static void pcpu_free_pages(struct pcpu_chunk *chunk,
* content of @pages and will pass it verbatim to pcpu_map_pages().
*/
static int pcpu_alloc_pages(struct pcpu_chunk *chunk,
- struct page **pages, unsigned long *populated,
- int page_start, int page_end)
+ struct page **pages, int page_start, int page_end)
{
const gfp_t gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD;
unsigned int cpu, tcpu;
@@ -164,7 +139,6 @@ static void __pcpu_unmap_pages(unsigned long addr, int nr_pages)
* pcpu_unmap_pages - unmap pages out of a pcpu_chunk
* @chunk: chunk of interest
* @pages: pages array which can be used to pass information to free
- * @populated: populated bitmap
* @page_start: page index of the first page to unmap
* @page_end: page index of the last page to unmap + 1
*
@@ -175,8 +149,7 @@ static void __pcpu_unmap_pages(unsigned long addr, int nr_pages)
* proper pre/post flush functions.
*/
static void pcpu_unmap_pages(struct pcpu_chunk *chunk,
- struct page **pages, unsigned long *populated,
- int page_start, int page_end)
+ struct page **pages, int page_start, int page_end)
{
unsigned int cpu;
int i;
@@ -192,8 +165,6 @@ static void pcpu_unmap_pages(struct pcpu_chunk *chunk,
__pcpu_unmap_pages(pcpu_chunk_addr(chunk, cpu, page_start),
page_end - page_start);
}
-
- bitmap_clear(populated, page_start, page_end - page_start);
}
/**
@@ -228,7 +199,6 @@ static int __pcpu_map_pages(unsigned long addr, struct page **pages,
* pcpu_map_pages - map pages into a pcpu_chunk
* @chunk: chunk of interest
* @pages: pages array containing pages to be mapped
- * @populated: populated bitmap
* @page_start: page index of the first page to map
* @page_end: page index of the last page to map + 1
*
@@ -236,13 +206,11 @@ static int __pcpu_map_pages(unsigned long addr, struct page **pages,
* caller is responsible for calling pcpu_post_map_flush() after all
* mappings are complete.
*
- * This function is responsible for setting corresponding bits in
- * @chunk->populated bitmap and whatever is necessary for reverse
- * lookup (addr -> chunk).
+ * This function is responsible for setting up whatever is necessary for
+ * reverse lookup (addr -> chunk).
*/
static int pcpu_map_pages(struct pcpu_chunk *chunk,
- struct page **pages, unsigned long *populated,
- int page_start, int page_end)
+ struct page **pages, int page_start, int page_end)
{
unsigned int cpu, tcpu;
int i, err;
@@ -253,18 +221,12 @@ static int pcpu_map_pages(struct pcpu_chunk *chunk,
page_end - page_start);
if (err < 0)
goto err;
- }
- /* mapping successful, link chunk and mark populated */
- for (i = page_start; i < page_end; i++) {
- for_each_possible_cpu(cpu)
+ for (i = page_start; i < page_end; i++)
pcpu_set_page_chunk(pages[pcpu_page_idx(cpu, i)],
chunk);
- __set_bit(i, populated);
}
-
return 0;
-
err:
for_each_possible_cpu(tcpu) {
if (tcpu == cpu)
@@ -299,123 +261,69 @@ static void pcpu_post_map_flush(struct pcpu_chunk *chunk,
/**
* pcpu_populate_chunk - populate and map an area of a pcpu_chunk
* @chunk: chunk of interest
- * @off: offset to the area to populate
- * @size: size of the area to populate in bytes
+ * @page_start: the start page
+ * @page_end: the end page
*
* For each cpu, populate and map pages [@page_start,@page_end) into
- * @chunk. The area is cleared on return.
+ * @chunk.
*
* CONTEXT:
* pcpu_alloc_mutex, does GFP_KERNEL allocation.
*/
-static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
+static int pcpu_populate_chunk(struct pcpu_chunk *chunk,
+ int page_start, int page_end)
{
- int page_start = PFN_DOWN(off);
- int page_end = PFN_UP(off + size);
- int free_end = page_start, unmap_end = page_start;
struct page **pages;
- unsigned long *populated;
- unsigned int cpu;
- int rs, re, rc;
-
- /* quick path, check whether all pages are already there */
- rs = page_start;
- pcpu_next_pop(chunk, &rs, &re, page_end);
- if (rs == page_start && re == page_end)
- goto clear;
- /* need to allocate and map pages, this chunk can't be immutable */
- WARN_ON(chunk->immutable);
-
- pages = pcpu_get_pages_and_bitmap(chunk, &populated, true);
+ pages = pcpu_get_pages(chunk);
if (!pages)
return -ENOMEM;
- /* alloc and map */
- pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
- rc = pcpu_alloc_pages(chunk, pages, populated, rs, re);
- if (rc)
- goto err_free;
- free_end = re;
- }
+ if (pcpu_alloc_pages(chunk, pages, page_start, page_end))
+ return -ENOMEM;
- pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
- rc = pcpu_map_pages(chunk, pages, populated, rs, re);
- if (rc)
- goto err_unmap;
- unmap_end = re;
+ if (pcpu_map_pages(chunk, pages, page_start, page_end)) {
+ pcpu_free_pages(chunk, pages, page_start, page_end);
+ return -ENOMEM;
}
pcpu_post_map_flush(chunk, page_start, page_end);
- /* commit new bitmap */
- bitmap_copy(chunk->populated, populated, pcpu_unit_pages);
-clear:
- for_each_possible_cpu(cpu)
- memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
return 0;
-
-err_unmap:
- pcpu_pre_unmap_flush(chunk, page_start, unmap_end);
- pcpu_for_each_unpop_region(chunk, rs, re, page_start, unmap_end)
- pcpu_unmap_pages(chunk, pages, populated, rs, re);
- pcpu_post_unmap_tlb_flush(chunk, page_start, unmap_end);
-err_free:
- pcpu_for_each_unpop_region(chunk, rs, re, page_start, free_end)
- pcpu_free_pages(chunk, pages, populated, rs, re);
- return rc;
}
/**
* pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk
* @chunk: chunk to depopulate
- * @off: offset to the area to depopulate
- * @size: size of the area to depopulate in bytes
+ * @page_start: the start page
+ * @page_end: the end page
*
* For each cpu, depopulate and unmap pages [@page_start,@page_end)
- * from @chunk. If @flush is true, vcache is flushed before unmapping
- * and tlb after.
+ * from @chunk.
*
* CONTEXT:
* pcpu_alloc_mutex.
*/
-static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size)
+static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk,
+ int page_start, int page_end)
{
- int page_start = PFN_DOWN(off);
- int page_end = PFN_UP(off + size);
struct page **pages;
- unsigned long *populated;
- int rs, re;
-
- /* quick path, check whether it's empty already */
- rs = page_start;
- pcpu_next_unpop(chunk, &rs, &re, page_end);
- if (rs == page_start && re == page_end)
- return;
-
- /* immutable chunks can't be depopulated */
- WARN_ON(chunk->immutable);
/*
* If control reaches here, there must have been at least one
* successful population attempt so the temp pages array must
* be available now.
*/
- pages = pcpu_get_pages_and_bitmap(chunk, &populated, false);
+ pages = pcpu_get_pages(chunk);
BUG_ON(!pages);
/* unmap and free */
pcpu_pre_unmap_flush(chunk, page_start, page_end);
- pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
- pcpu_unmap_pages(chunk, pages, populated, rs, re);
+ pcpu_unmap_pages(chunk, pages, page_start, page_end);
/* no need to flush tlb, vmalloc will handle it lazily */
- pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
- pcpu_free_pages(chunk, pages, populated, rs, re);
-
- /* commit new bitmap */
- bitmap_copy(chunk->populated, populated, pcpu_unit_pages);
+ pcpu_free_pages(chunk, pages, page_start, page_end);
}
static struct pcpu_chunk *pcpu_create_chunk(void)
diff --git a/mm/percpu.c b/mm/percpu.c
index da997f9800b..014bab65e0f 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -76,6 +76,10 @@
#define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */
#define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */
+#define PCPU_ATOMIC_MAP_MARGIN_LOW 32
+#define PCPU_ATOMIC_MAP_MARGIN_HIGH 64
+#define PCPU_EMPTY_POP_PAGES_LOW 2
+#define PCPU_EMPTY_POP_PAGES_HIGH 4
#ifdef CONFIG_SMP
/* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */
@@ -102,12 +106,16 @@ struct pcpu_chunk {
int free_size; /* free bytes in the chunk */
int contig_hint; /* max contiguous size hint */
void *base_addr; /* base address of this chunk */
+
int map_used; /* # of map entries used before the sentry */
int map_alloc; /* # of map entries allocated */
int *map; /* allocation map */
+ struct work_struct map_extend_work;/* async ->map[] extension */
+
void *data; /* chunk data */
int first_free; /* no free below this */
bool immutable; /* no [de]population allowed */
+ int nr_populated; /* # of populated pages */
unsigned long populated[]; /* populated bitmap */
};
@@ -151,38 +159,33 @@ static struct pcpu_chunk *pcpu_first_chunk;
static struct pcpu_chunk *pcpu_reserved_chunk;
static int pcpu_reserved_chunk_limit;
+static DEFINE_SPINLOCK(pcpu_lock); /* all internal data structures */
+static DEFINE_MUTEX(pcpu_alloc_mutex); /* chunk create/destroy, [de]pop */
+
+static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */
+
/*
- * Synchronization rules.
- *
- * There are two locks - pcpu_alloc_mutex and pcpu_lock. The former
- * protects allocation/reclaim paths, chunks, populated bitmap and
- * vmalloc mapping. The latter is a spinlock and protects the index
- * data structures - chunk slots, chunks and area maps in chunks.
- *
- * During allocation, pcpu_alloc_mutex is kept locked all the time and
- * pcpu_lock is grabbed and released as necessary. All actual memory
- * allocations are done using GFP_KERNEL with pcpu_lock released. In
- * general, percpu memory can't be allocated with irq off but
- * irqsave/restore are still used in alloc path so that it can be used
- * from early init path - sched_init() specifically.
- *
- * Free path accesses and alters only the index data structures, so it
- * can be safely called from atomic context. When memory needs to be
- * returned to the system, free path schedules reclaim_work which
- * grabs both pcpu_alloc_mutex and pcpu_lock, unlinks chunks to be
- * reclaimed, release both locks and frees the chunks. Note that it's
- * necessary to grab both locks to remove a chunk from circulation as
- * allocation path might be referencing the chunk with only
- * pcpu_alloc_mutex locked.
+ * The number of empty populated pages, protected by pcpu_lock. The
+ * reserved chunk doesn't contribute to the count.
*/
-static DEFINE_MUTEX(pcpu_alloc_mutex); /* protects whole alloc and reclaim */
-static DEFINE_SPINLOCK(pcpu_lock); /* protects index data structures */
+static int pcpu_nr_empty_pop_pages;
-static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */
+/*
+ * Balance work is used to populate or destroy chunks asynchronously. We
+ * try to keep the number of populated free pages between
+ * PCPU_EMPTY_POP_PAGES_LOW and HIGH for atomic allocations and at most one
+ * empty chunk.
+ */
+static void pcpu_balance_workfn(struct work_struct *work);
+static DECLARE_WORK(pcpu_balance_work, pcpu_balance_workfn);
+static bool pcpu_async_enabled __read_mostly;
+static bool pcpu_atomic_alloc_failed;
-/* reclaim work to release fully free chunks, scheduled from free path */
-static void pcpu_reclaim(struct work_struct *work);
-static DECLARE_WORK(pcpu_reclaim_work, pcpu_reclaim);
+static void pcpu_schedule_balance_work(void)
+{
+ if (pcpu_async_enabled)
+ schedule_work(&pcpu_balance_work);
+}
static bool pcpu_addr_in_first_chunk(void *addr)
{
@@ -315,6 +318,38 @@ static void pcpu_mem_free(void *ptr, size_t size)
}
/**
+ * pcpu_count_occupied_pages - count the number of pages an area occupies
+ * @chunk: chunk of interest
+ * @i: index of the area in question
+ *
+ * Count the number of pages chunk's @i'th area occupies. When the area's
+ * start and/or end address isn't aligned to page boundary, the straddled
+ * page is included in the count iff the rest of the page is free.
+ */
+static int pcpu_count_occupied_pages(struct pcpu_chunk *chunk, int i)
+{
+ int off = chunk->map[i] & ~1;
+ int end = chunk->map[i + 1] & ~1;
+
+ if (!PAGE_ALIGNED(off) && i > 0) {
+ int prev = chunk->map[i - 1];
+
+ if (!(prev & 1) && prev <= round_down(off, PAGE_SIZE))
+ off = round_down(off, PAGE_SIZE);
+ }
+
+ if (!PAGE_ALIGNED(end) && i + 1 < chunk->map_used) {
+ int next = chunk->map[i + 1];
+ int nend = chunk->map[i + 2] & ~1;
+
+ if (!(next & 1) && nend >= round_up(end, PAGE_SIZE))
+ end = round_up(end, PAGE_SIZE);
+ }
+
+ return max_t(int, PFN_DOWN(end) - PFN_UP(off), 0);
+}
+
+/**
* pcpu_chunk_relocate - put chunk in the appropriate chunk slot
* @chunk: chunk of interest
* @oslot: the previous slot it was on
@@ -342,9 +377,14 @@ static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
/**
* pcpu_need_to_extend - determine whether chunk area map needs to be extended
* @chunk: chunk of interest
+ * @is_atomic: the allocation context
*
- * Determine whether area map of @chunk needs to be extended to
- * accommodate a new allocation.
+ * Determine whether area map of @chunk needs to be extended. If
+ * @is_atomic, only the amount necessary for a new allocation is
+ * considered; however, async extension is scheduled if the left amount is
+ * low. If !@is_atomic, it aims for more empty space. Combined, this
+ * ensures that the map is likely to have enough available space to
+ * accomodate atomic allocations which can't extend maps directly.
*
* CONTEXT:
* pcpu_lock.
@@ -353,15 +393,26 @@ static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
* New target map allocation length if extension is necessary, 0
* otherwise.
*/
-static int pcpu_need_to_extend(struct pcpu_chunk *chunk)
+static int pcpu_need_to_extend(struct pcpu_chunk *chunk, bool is_atomic)
{
- int new_alloc;
+ int margin, new_alloc;
+
+ if (is_atomic) {
+ margin = 3;
+
+ if (chunk->map_alloc <
+ chunk->map_used + PCPU_ATOMIC_MAP_MARGIN_LOW &&
+ pcpu_async_enabled)
+ schedule_work(&chunk->map_extend_work);
+ } else {
+ margin = PCPU_ATOMIC_MAP_MARGIN_HIGH;
+ }
- if (chunk->map_alloc >= chunk->map_used + 3)
+ if (chunk->map_alloc >= chunk->map_used + margin)
return 0;
new_alloc = PCPU_DFL_MAP_ALLOC;
- while (new_alloc < chunk->map_used + 3)
+ while (new_alloc < chunk->map_used + margin)
new_alloc *= 2;
return new_alloc;
@@ -418,11 +469,76 @@ out_unlock:
return 0;
}
+static void pcpu_map_extend_workfn(struct work_struct *work)
+{
+ struct pcpu_chunk *chunk = container_of(work, struct pcpu_chunk,
+ map_extend_work);
+ int new_alloc;
+
+ spin_lock_irq(&pcpu_lock);
+ new_alloc = pcpu_need_to_extend(chunk, false);
+ spin_unlock_irq(&pcpu_lock);
+
+ if (new_alloc)
+ pcpu_extend_area_map(chunk, new_alloc);
+}
+
+/**
+ * pcpu_fit_in_area - try to fit the requested allocation in a candidate area
+ * @chunk: chunk the candidate area belongs to
+ * @off: the offset to the start of the candidate area
+ * @this_size: the size of the candidate area
+ * @size: the size of the target allocation
+ * @align: the alignment of the target allocation
+ * @pop_only: only allocate from already populated region
+ *
+ * We're trying to allocate @size bytes aligned at @align. @chunk's area
+ * at @off sized @this_size is a candidate. This function determines
+ * whether the target allocation fits in the candidate area and returns the
+ * number of bytes to pad after @off. If the target area doesn't fit, -1
+ * is returned.
+ *
+ * If @pop_only is %true, this function only considers the already
+ * populated part of the candidate area.
+ */
+static int pcpu_fit_in_area(struct pcpu_chunk *chunk, int off, int this_size,
+ int size, int align, bool pop_only)
+{
+ int cand_off = off;
+
+ while (true) {
+ int head = ALIGN(cand_off, align) - off;
+ int page_start, page_end, rs, re;
+
+ if (this_size < head + size)
+ return -1;
+
+ if (!pop_only)
+ return head;
+
+ /*
+ * If the first unpopulated page is beyond the end of the
+ * allocation, the whole allocation is populated;
+ * otherwise, retry from the end of the unpopulated area.
+ */
+ page_start = PFN_DOWN(head + off);
+ page_end = PFN_UP(head + off + size);
+
+ rs = page_start;
+ pcpu_next_unpop(chunk, &rs, &re, PFN_UP(off + this_size));
+ if (rs >= page_end)
+ return head;
+ cand_off = re * PAGE_SIZE;
+ }
+}
+
/**
* pcpu_alloc_area - allocate area from a pcpu_chunk
* @chunk: chunk of interest
* @size: wanted size in bytes
* @align: wanted align
+ * @pop_only: allocate only from the populated area
+ * @occ_pages_p: out param for the number of pages the area occupies
*
* Try to allocate @size bytes area aligned at @align from @chunk.
* Note that this function only allocates the offset. It doesn't
@@ -437,7 +553,8 @@ out_unlock:
* Allocated offset in @chunk on success, -1 if no matching area is
* found.
*/
-static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align)
+static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align,
+ bool pop_only, int *occ_pages_p)
{
int oslot = pcpu_chunk_slot(chunk);
int max_contig = 0;
@@ -453,11 +570,11 @@ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align)
if (off & 1)
continue;
- /* extra for alignment requirement */
- head = ALIGN(off, align) - off;
-
this_size = (p[1] & ~1) - off;
- if (this_size < head + size) {
+
+ head = pcpu_fit_in_area(chunk, off, this_size, size, align,
+ pop_only);
+ if (head < 0) {
if (!seen_free) {
chunk->first_free = i;
seen_free = true;
@@ -526,6 +643,7 @@ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align)
chunk->free_size -= size;
*p |= 1;
+ *occ_pages_p = pcpu_count_occupied_pages(chunk, i);
pcpu_chunk_relocate(chunk, oslot);
return off;
}
@@ -541,6 +659,7 @@ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align)
* pcpu_free_area - free area to a pcpu_chunk
* @chunk: chunk of interest
* @freeme: offset of area to free
+ * @occ_pages_p: out param for the number of pages the area occupies
*
* Free area starting from @freeme to @chunk. Note that this function
* only modifies the allocation map. It doesn't depopulate or unmap
@@ -549,7 +668,8 @@ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align)
* CONTEXT:
* pcpu_lock.
*/
-static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme)
+static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme,
+ int *occ_pages_p)
{
int oslot = pcpu_chunk_slot(chunk);
int off = 0;
@@ -580,6 +700,8 @@ static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme)
*p = off &= ~1;
chunk->free_size += (p[1] & ~1) - off;
+ *occ_pages_p = pcpu_count_occupied_pages(chunk, i);
+
/* merge with next? */
if (!(p[1] & 1))
to_free++;
@@ -620,6 +742,7 @@ static struct pcpu_chunk *pcpu_alloc_chunk(void)
chunk->map_used = 1;
INIT_LIST_HEAD(&chunk->list);
+ INIT_WORK(&chunk->map_extend_work, pcpu_map_extend_workfn);
chunk->free_size = pcpu_unit_size;
chunk->contig_hint = pcpu_unit_size;
@@ -634,6 +757,50 @@ static void pcpu_free_chunk(struct pcpu_chunk *chunk)
pcpu_mem_free(chunk, pcpu_chunk_struct_size);
}
+/**
+ * pcpu_chunk_populated - post-population bookkeeping
+ * @chunk: pcpu_chunk which got populated
+ * @page_start: the start page
+ * @page_end: the end page
+ *
+ * Pages in [@page_start,@page_end) have been populated to @chunk. Update
+ * the bookkeeping information accordingly. Must be called after each
+ * successful population.
+ */
+static void pcpu_chunk_populated(struct pcpu_chunk *chunk,
+ int page_start, int page_end)
+{
+ int nr = page_end - page_start;
+
+ lockdep_assert_held(&pcpu_lock);
+
+ bitmap_set(chunk->populated, page_start, nr);
+ chunk->nr_populated += nr;
+ pcpu_nr_empty_pop_pages += nr;
+}
+
+/**
+ * pcpu_chunk_depopulated - post-depopulation bookkeeping
+ * @chunk: pcpu_chunk which got depopulated
+ * @page_start: the start page
+ * @page_end: the end page
+ *
+ * Pages in [@page_start,@page_end) have been depopulated from @chunk.
+ * Update the bookkeeping information accordingly. Must be called after
+ * each successful depopulation.
+ */
+static void pcpu_chunk_depopulated(struct pcpu_chunk *chunk,
+ int page_start, int page_end)
+{
+ int nr = page_end - page_start;
+
+ lockdep_assert_held(&pcpu_lock);
+
+ bitmap_clear(chunk->populated, page_start, nr);
+ chunk->nr_populated -= nr;
+ pcpu_nr_empty_pop_pages -= nr;
+}
+
/*
* Chunk management implementation.
*
@@ -695,21 +862,23 @@ static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
* @size: size of area to allocate in bytes
* @align: alignment of area (max PAGE_SIZE)
* @reserved: allocate from the reserved chunk if available
+ * @gfp: allocation flags
*
- * Allocate percpu area of @size bytes aligned at @align.
- *
- * CONTEXT:
- * Does GFP_KERNEL allocation.
+ * Allocate percpu area of @size bytes aligned at @align. If @gfp doesn't
+ * contain %GFP_KERNEL, the allocation is atomic.
*
* RETURNS:
* Percpu pointer to the allocated area on success, NULL on failure.
*/
-static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved)
+static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved,
+ gfp_t gfp)
{
static int warn_limit = 10;
struct pcpu_chunk *chunk;
const char *err;
- int slot, off, new_alloc;
+ bool is_atomic = (gfp & GFP_KERNEL) != GFP_KERNEL;
+ int occ_pages = 0;
+ int slot, off, new_alloc, cpu, ret;
unsigned long flags;
void __percpu *ptr;
@@ -728,7 +897,6 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved)
return NULL;
}
- mutex_lock(&pcpu_alloc_mutex);
spin_lock_irqsave(&pcpu_lock, flags);
/* serve reserved allocations from the reserved chunk if available */
@@ -740,16 +908,18 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved)
goto fail_unlock;
}
- while ((new_alloc = pcpu_need_to_extend(chunk))) {
+ while ((new_alloc = pcpu_need_to_extend(chunk, is_atomic))) {
spin_unlock_irqrestore(&pcpu_lock, flags);
- if (pcpu_extend_area_map(chunk, new_alloc) < 0) {
+ if (is_atomic ||
+ pcpu_extend_area_map(chunk, new_alloc) < 0) {
err = "failed to extend area map of reserved chunk";
- goto fail_unlock_mutex;
+ goto fail;
}
spin_lock_irqsave(&pcpu_lock, flags);
}
- off = pcpu_alloc_area(chunk, size, align);
+ off = pcpu_alloc_area(chunk, size, align, is_atomic,
+ &occ_pages);
if (off >= 0)
goto area_found;
@@ -764,13 +934,15 @@ restart:
if (size > chunk->contig_hint)
continue;
- new_alloc = pcpu_need_to_extend(chunk);
+ new_alloc = pcpu_need_to_extend(chunk, is_atomic);
if (new_alloc) {
+ if (is_atomic)
+ continue;
spin_unlock_irqrestore(&pcpu_lock, flags);
if (pcpu_extend_area_map(chunk,
new_alloc) < 0) {
err = "failed to extend area map";
- goto fail_unlock_mutex;
+ goto fail;
}
spin_lock_irqsave(&pcpu_lock, flags);
/*
@@ -780,74 +952,134 @@ restart:
goto restart;
}
- off = pcpu_alloc_area(chunk, size, align);
+ off = pcpu_alloc_area(chunk, size, align, is_atomic,
+ &occ_pages);
if (off >= 0)
goto area_found;
}
}
- /* hmmm... no space left, create a new chunk */
spin_unlock_irqrestore(&pcpu_lock, flags);
- chunk = pcpu_create_chunk();
- if (!chunk) {
- err = "failed to allocate new chunk";
- goto fail_unlock_mutex;
+ /*
+ * No space left. Create a new chunk. We don't want multiple
+ * tasks to create chunks simultaneously. Serialize and create iff
+ * there's still no empty chunk after grabbing the mutex.
+ */
+ if (is_atomic)
+ goto fail;
+
+ mutex_lock(&pcpu_alloc_mutex);
+
+ if (list_empty(&pcpu_slot[pcpu_nr_slots - 1])) {
+ chunk = pcpu_create_chunk();
+ if (!chunk) {
+ mutex_unlock(&pcpu_alloc_mutex);
+ err = "failed to allocate new chunk";
+ goto fail;
+ }
+
+ spin_lock_irqsave(&pcpu_lock, flags);
+ pcpu_chunk_relocate(chunk, -1);
+ } else {
+ spin_lock_irqsave(&pcpu_lock, flags);
}
- spin_lock_irqsave(&pcpu_lock, flags);
- pcpu_chunk_relocate(chunk, -1);
+ mutex_unlock(&pcpu_alloc_mutex);
goto restart;
area_found:
spin_unlock_irqrestore(&pcpu_lock, flags);
- /* populate, map and clear the area */
- if (pcpu_populate_chunk(chunk, off, size)) {
- spin_lock_irqsave(&pcpu_lock, flags);
- pcpu_free_area(chunk, off);
- err = "failed to populate";
- goto fail_unlock;
+ /* populate if not all pages are already there */
+ if (!is_atomic) {
+ int page_start, page_end, rs, re;
+
+ mutex_lock(&pcpu_alloc_mutex);
+
+ page_start = PFN_DOWN(off);
+ page_end = PFN_UP(off + size);
+
+ pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
+ WARN_ON(chunk->immutable);
+
+ ret = pcpu_populate_chunk(chunk, rs, re);
+
+ spin_lock_irqsave(&pcpu_lock, flags);
+ if (ret) {
+ mutex_unlock(&pcpu_alloc_mutex);
+ pcpu_free_area(chunk, off, &occ_pages);
+ err = "failed to populate";
+ goto fail_unlock;
+ }
+ pcpu_chunk_populated(chunk, rs, re);
+ spin_unlock_irqrestore(&pcpu_lock, flags);
+ }
+
+ mutex_unlock(&pcpu_alloc_mutex);
}
- mutex_unlock(&pcpu_alloc_mutex);
+ if (chunk != pcpu_reserved_chunk)
+ pcpu_nr_empty_pop_pages -= occ_pages;
+
+ if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW)
+ pcpu_schedule_balance_work();
+
+ /* clear the areas and return address relative to base address */
+ for_each_possible_cpu(cpu)
+ memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
- /* return address relative to base address */
ptr = __addr_to_pcpu_ptr(chunk->base_addr + off);
kmemleak_alloc_percpu(ptr, size);
return ptr;
fail_unlock:
spin_unlock_irqrestore(&pcpu_lock, flags);
-fail_unlock_mutex:
- mutex_unlock(&pcpu_alloc_mutex);
- if (warn_limit) {
- pr_warning("PERCPU: allocation failed, size=%zu align=%zu, "
- "%s\n", size, align, err);
+fail:
+ if (!is_atomic && warn_limit) {
+ pr_warning("PERCPU: allocation failed, size=%zu align=%zu atomic=%d, %s\n",
+ size, align, is_atomic, err);
dump_stack();
if (!--warn_limit)
pr_info("PERCPU: limit reached, disable warning\n");
}
+ if (is_atomic) {
+ /* see the flag handling in pcpu_blance_workfn() */
+ pcpu_atomic_alloc_failed = true;
+ pcpu_schedule_balance_work();
+ }
return NULL;
}
/**
- * __alloc_percpu - allocate dynamic percpu area
+ * __alloc_percpu_gfp - allocate dynamic percpu area
* @size: size of area to allocate in bytes
* @align: alignment of area (max PAGE_SIZE)
+ * @gfp: allocation flags
*
- * Allocate zero-filled percpu area of @size bytes aligned at @align.
- * Might sleep. Might trigger writeouts.
- *
- * CONTEXT:
- * Does GFP_KERNEL allocation.
+ * Allocate zero-filled percpu area of @size bytes aligned at @align. If
+ * @gfp doesn't contain %GFP_KERNEL, the allocation doesn't block and can
+ * be called from any context but is a lot more likely to fail.
*
* RETURNS:
* Percpu pointer to the allocated area on success, NULL on failure.
*/
+void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp)
+{
+ return pcpu_alloc(size, align, false, gfp);
+}
+EXPORT_SYMBOL_GPL(__alloc_percpu_gfp);
+
+/**
+ * __alloc_percpu - allocate dynamic percpu area
+ * @size: size of area to allocate in bytes
+ * @align: alignment of area (max PAGE_SIZE)
+ *
+ * Equivalent to __alloc_percpu_gfp(size, align, %GFP_KERNEL).
+ */
void __percpu *__alloc_percpu(size_t size, size_t align)
{
- return pcpu_alloc(size, align, false);
+ return pcpu_alloc(size, align, false, GFP_KERNEL);
}
EXPORT_SYMBOL_GPL(__alloc_percpu);
@@ -869,44 +1101,121 @@ EXPORT_SYMBOL_GPL(__alloc_percpu);
*/
void __percpu *__alloc_reserved_percpu(size_t size, size_t align)
{
- return pcpu_alloc(size, align, true);
+ return pcpu_alloc(size, align, true, GFP_KERNEL);
}
/**
- * pcpu_reclaim - reclaim fully free chunks, workqueue function
+ * pcpu_balance_workfn - manage the amount of free chunks and populated pages
* @work: unused
*
* Reclaim all fully free chunks except for the first one.
- *
- * CONTEXT:
- * workqueue context.
*/
-static void pcpu_reclaim(struct work_struct *work)
+static void pcpu_balance_workfn(struct work_struct *work)
{
- LIST_HEAD(todo);
- struct list_head *head = &pcpu_slot[pcpu_nr_slots - 1];
+ LIST_HEAD(to_free);
+ struct list_head *free_head = &pcpu_slot[pcpu_nr_slots - 1];
struct pcpu_chunk *chunk, *next;
+ int slot, nr_to_pop, ret;
+ /*
+ * There's no reason to keep around multiple unused chunks and VM
+ * areas can be scarce. Destroy all free chunks except for one.
+ */
mutex_lock(&pcpu_alloc_mutex);
spin_lock_irq(&pcpu_lock);
- list_for_each_entry_safe(chunk, next, head, list) {
+ list_for_each_entry_safe(chunk, next, free_head, list) {
WARN_ON(chunk->immutable);
/* spare the first one */
- if (chunk == list_first_entry(head, struct pcpu_chunk, list))
+ if (chunk == list_first_entry(free_head, struct pcpu_chunk, list))
continue;
- list_move(&chunk->list, &todo);
+ list_move(&chunk->list, &to_free);
}
spin_unlock_irq(&pcpu_lock);
- list_for_each_entry_safe(chunk, next, &todo, list) {
- pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size);
+ list_for_each_entry_safe(chunk, next, &to_free, list) {
+ int rs, re;
+
+ pcpu_for_each_pop_region(chunk, rs, re, 0, pcpu_unit_pages) {
+ pcpu_depopulate_chunk(chunk, rs, re);
+ spin_lock_irq(&pcpu_lock);
+ pcpu_chunk_depopulated(chunk, rs, re);
+ spin_unlock_irq(&pcpu_lock);
+ }
pcpu_destroy_chunk(chunk);
}
+ /*
+ * Ensure there are certain number of free populated pages for
+ * atomic allocs. Fill up from the most packed so that atomic
+ * allocs don't increase fragmentation. If atomic allocation
+ * failed previously, always populate the maximum amount. This
+ * should prevent atomic allocs larger than PAGE_SIZE from keeping
+ * failing indefinitely; however, large atomic allocs are not
+ * something we support properly and can be highly unreliable and
+ * inefficient.
+ */
+retry_pop:
+ if (pcpu_atomic_alloc_failed) {
+ nr_to_pop = PCPU_EMPTY_POP_PAGES_HIGH;
+ /* best effort anyway, don't worry about synchronization */
+ pcpu_atomic_alloc_failed = false;
+ } else {
+ nr_to_pop = clamp(PCPU_EMPTY_POP_PAGES_HIGH -
+ pcpu_nr_empty_pop_pages,
+ 0, PCPU_EMPTY_POP_PAGES_HIGH);
+ }
+
+ for (slot = pcpu_size_to_slot(PAGE_SIZE); slot < pcpu_nr_slots; slot++) {
+ int nr_unpop = 0, rs, re;
+
+ if (!nr_to_pop)
+ break;
+
+ spin_lock_irq(&pcpu_lock);
+ list_for_each_entry(chunk, &pcpu_slot[slot], list) {
+ nr_unpop = pcpu_unit_pages - chunk->nr_populated;
+ if (nr_unpop)
+ break;
+ }
+ spin_unlock_irq(&pcpu_lock);
+
+ if (!nr_unpop)
+ continue;
+
+ /* @chunk can't go away while pcpu_alloc_mutex is held */
+ pcpu_for_each_unpop_region(chunk, rs, re, 0, pcpu_unit_pages) {
+ int nr = min(re - rs, nr_to_pop);
+
+ ret = pcpu_populate_chunk(chunk, rs, rs + nr);
+ if (!ret) {
+ nr_to_pop -= nr;
+ spin_lock_irq(&pcpu_lock);
+ pcpu_chunk_populated(chunk, rs, rs + nr);
+ spin_unlock_irq(&pcpu_lock);
+ } else {
+ nr_to_pop = 0;
+ }
+
+ if (!nr_to_pop)
+ break;
+ }
+ }
+
+ if (nr_to_pop) {
+ /* ran out of chunks to populate, create a new one and retry */
+ chunk = pcpu_create_chunk();
+ if (chunk) {
+ spin_lock_irq(&pcpu_lock);
+ pcpu_chunk_relocate(chunk, -1);
+ spin_unlock_irq(&pcpu_lock);
+ goto retry_pop;
+ }
+ }
+
mutex_unlock(&pcpu_alloc_mutex);
}
@@ -924,7 +1233,7 @@ void free_percpu(void __percpu *ptr)
void *addr;
struct pcpu_chunk *chunk;
unsigned long flags;
- int off;
+ int off, occ_pages;
if (!ptr)
return;
@@ -938,7 +1247,10 @@ void free_percpu(void __percpu *ptr)
chunk = pcpu_chunk_addr_search(addr);
off = addr - chunk->base_addr;
- pcpu_free_area(chunk, off);
+ pcpu_free_area(chunk, off, &occ_pages);
+
+ if (chunk != pcpu_reserved_chunk)
+ pcpu_nr_empty_pop_pages += occ_pages;
/* if there are more than one fully free chunks, wake up grim reaper */
if (chunk->free_size == pcpu_unit_size) {
@@ -946,7 +1258,7 @@ void free_percpu(void __percpu *ptr)
list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list)
if (pos != chunk) {
- schedule_work(&pcpu_reclaim_work);
+ pcpu_schedule_balance_work();
break;
}
}
@@ -1336,11 +1648,13 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
*/
schunk = memblock_virt_alloc(pcpu_chunk_struct_size, 0);
INIT_LIST_HEAD(&schunk->list);
+ INIT_WORK(&schunk->map_extend_work, pcpu_map_extend_workfn);
schunk->base_addr = base_addr;
schunk->map = smap;
schunk->map_alloc = ARRAY_SIZE(smap);
schunk->immutable = true;
bitmap_fill(schunk->populated, pcpu_unit_pages);
+ schunk->nr_populated = pcpu_unit_pages;
if (ai->reserved_size) {
schunk->free_size = ai->reserved_size;
@@ -1364,11 +1678,13 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
if (dyn_size) {
dchunk = memblock_virt_alloc(pcpu_chunk_struct_size, 0);
INIT_LIST_HEAD(&dchunk->list);
+ INIT_WORK(&dchunk->map_extend_work, pcpu_map_extend_workfn);
dchunk->base_addr = base_addr;
dchunk->map = dmap;
dchunk->map_alloc = ARRAY_SIZE(dmap);
dchunk->immutable = true;
bitmap_fill(dchunk->populated, pcpu_unit_pages);
+ dchunk->nr_populated = pcpu_unit_pages;
dchunk->contig_hint = dchunk->free_size = dyn_size;
dchunk->map[0] = 1;
@@ -1379,6 +1695,8 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
/* link the first chunk in */
pcpu_first_chunk = dchunk ?: schunk;
+ pcpu_nr_empty_pop_pages +=
+ pcpu_count_occupied_pages(pcpu_first_chunk, 1);
pcpu_chunk_relocate(pcpu_first_chunk, -1);
/* we're done */
@@ -1932,8 +2250,6 @@ void __init setup_per_cpu_areas(void)
if (pcpu_setup_first_chunk(ai, fc) < 0)
panic("Failed to initialize percpu areas.");
-
- pcpu_free_alloc_info(ai);
}
#endif /* CONFIG_SMP */
@@ -1967,3 +2283,15 @@ void __init percpu_init_late(void)
spin_unlock_irqrestore(&pcpu_lock, flags);
}
}
+
+/*
+ * Percpu allocator is initialized early during boot when neither slab or
+ * workqueue is available. Plug async management until everything is up
+ * and running.
+ */
+static int __init percpu_enable_async(void)
+{
+ pcpu_async_enabled = true;
+ return 0;
+}
+subsys_initcall(percpu_enable_async);
diff --git a/mm/shmem.c b/mm/shmem.c
index 4fad61bb41e..cd6fc7590e5 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2995,7 +2995,7 @@ int shmem_fill_super(struct super_block *sb, void *data, int silent)
#endif
spin_lock_init(&sbinfo->stat_lock);
- if (percpu_counter_init(&sbinfo->used_blocks, 0))
+ if (percpu_counter_init(&sbinfo->used_blocks, 0, GFP_KERNEL))
goto failed;
sbinfo->free_inodes = sbinfo->max_inodes;
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 97b0fcc7954..5ab6627cf37 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -1115,7 +1115,7 @@ static int __init dccp_init(void)
BUILD_BUG_ON(sizeof(struct dccp_skb_cb) >
FIELD_SIZEOF(struct sk_buff, cb));
- rc = percpu_counter_init(&dccp_orphan_count, 0);
+ rc = percpu_counter_init(&dccp_orphan_count, 0, GFP_KERNEL);
if (rc)
goto out_fail;
rc = -ENOBUFS;
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 461003d258b..86023b9be47 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3071,8 +3071,8 @@ void __init tcp_init(void)
BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
- percpu_counter_init(&tcp_sockets_allocated, 0);
- percpu_counter_init(&tcp_orphan_count, 0);
+ percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
+ percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL);
tcp_hashinfo.bind_bucket_cachep =
kmem_cache_create("tcp_bind_bucket",
sizeof(struct inet_bind_bucket), 0,
diff --git a/net/ipv4/tcp_memcontrol.c b/net/ipv4/tcp_memcontrol.c
index 3af522622fa..1d191357bf8 100644
--- a/net/ipv4/tcp_memcontrol.c
+++ b/net/ipv4/tcp_memcontrol.c
@@ -32,7 +32,7 @@ int tcp_init_cgroup(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
res_parent = &parent_cg->memory_allocated;
res_counter_init(&cg_proto->memory_allocated, res_parent);
- percpu_counter_init(&cg_proto->sockets_allocated, 0);
+ percpu_counter_init(&cg_proto->sockets_allocated, 0, GFP_KERNEL);
return 0;
}
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 9d2c6c9facb..8f34b27d577 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -1341,7 +1341,7 @@ static __init int sctp_init(void)
if (!sctp_chunk_cachep)
goto err_chunk_cachep;
- status = percpu_counter_init(&sctp_sockets_allocated, 0);
+ status = percpu_counter_init(&sctp_sockets_allocated, 0, GFP_KERNEL);
if (status)
goto err_percpu_counter_init;