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-rw-r--r--mm/percpu.c112
1 files changed, 84 insertions, 28 deletions
diff --git a/mm/percpu.c b/mm/percpu.c
index 43d8cacfdaa..d90797160c2 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -153,7 +153,10 @@ static int pcpu_reserved_chunk_limit;
*
* 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.
+ * 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
@@ -366,7 +369,7 @@ static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
* RETURNS:
* 0 if noop, 1 if successfully extended, -errno on failure.
*/
-static int pcpu_extend_area_map(struct pcpu_chunk *chunk)
+static int pcpu_extend_area_map(struct pcpu_chunk *chunk, unsigned long *flags)
{
int new_alloc;
int *new;
@@ -376,7 +379,7 @@ static int pcpu_extend_area_map(struct pcpu_chunk *chunk)
if (chunk->map_alloc >= chunk->map_used + 2)
return 0;
- spin_unlock_irq(&pcpu_lock);
+ spin_unlock_irqrestore(&pcpu_lock, *flags);
new_alloc = PCPU_DFL_MAP_ALLOC;
while (new_alloc < chunk->map_used + 2)
@@ -384,7 +387,7 @@ static int pcpu_extend_area_map(struct pcpu_chunk *chunk)
new = pcpu_mem_alloc(new_alloc * sizeof(new[0]));
if (!new) {
- spin_lock_irq(&pcpu_lock);
+ spin_lock_irqsave(&pcpu_lock, *flags);
return -ENOMEM;
}
@@ -393,7 +396,7 @@ static int pcpu_extend_area_map(struct pcpu_chunk *chunk)
* could have happened inbetween, so map_used couldn't have
* grown.
*/
- spin_lock_irq(&pcpu_lock);
+ spin_lock_irqsave(&pcpu_lock, *flags);
BUG_ON(new_alloc < chunk->map_used + 2);
size = chunk->map_alloc * sizeof(chunk->map[0]);
@@ -1043,8 +1046,11 @@ static struct pcpu_chunk *alloc_pcpu_chunk(void)
*/
static void *pcpu_alloc(size_t size, size_t align, bool reserved)
{
+ static int warn_limit = 10;
struct pcpu_chunk *chunk;
+ const char *err;
int slot, off;
+ unsigned long flags;
if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
WARN(true, "illegal size (%zu) or align (%zu) for "
@@ -1053,17 +1059,20 @@ static void *pcpu_alloc(size_t size, size_t align, bool reserved)
}
mutex_lock(&pcpu_alloc_mutex);
- spin_lock_irq(&pcpu_lock);
+ spin_lock_irqsave(&pcpu_lock, flags);
/* serve reserved allocations from the reserved chunk if available */
if (reserved && pcpu_reserved_chunk) {
chunk = pcpu_reserved_chunk;
if (size > chunk->contig_hint ||
- pcpu_extend_area_map(chunk) < 0)
+ pcpu_extend_area_map(chunk, &flags) < 0) {
+ err = "failed to extend area map of reserved chunk";
goto fail_unlock;
+ }
off = pcpu_alloc_area(chunk, size, align);
if (off >= 0)
goto area_found;
+ err = "alloc from reserved chunk failed";
goto fail_unlock;
}
@@ -1074,12 +1083,13 @@ restart:
if (size > chunk->contig_hint)
continue;
- switch (pcpu_extend_area_map(chunk)) {
+ switch (pcpu_extend_area_map(chunk, &flags)) {
case 0:
break;
case 1:
goto restart; /* pcpu_lock dropped, restart */
default:
+ err = "failed to extend area map";
goto fail_unlock;
}
@@ -1090,23 +1100,26 @@ restart:
}
/* hmmm... no space left, create a new chunk */
- spin_unlock_irq(&pcpu_lock);
+ spin_unlock_irqrestore(&pcpu_lock, flags);
chunk = alloc_pcpu_chunk();
- if (!chunk)
+ if (!chunk) {
+ err = "failed to allocate new chunk";
goto fail_unlock_mutex;
+ }
- spin_lock_irq(&pcpu_lock);
+ spin_lock_irqsave(&pcpu_lock, flags);
pcpu_chunk_relocate(chunk, -1);
goto restart;
area_found:
- spin_unlock_irq(&pcpu_lock);
+ spin_unlock_irqrestore(&pcpu_lock, flags);
/* populate, map and clear the area */
if (pcpu_populate_chunk(chunk, off, size)) {
- spin_lock_irq(&pcpu_lock);
+ spin_lock_irqsave(&pcpu_lock, flags);
pcpu_free_area(chunk, off);
+ err = "failed to populate";
goto fail_unlock;
}
@@ -1116,9 +1129,16 @@ area_found:
return __addr_to_pcpu_ptr(chunk->base_addr + off);
fail_unlock:
- spin_unlock_irq(&pcpu_lock);
+ 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);
+ dump_stack();
+ if (!--warn_limit)
+ pr_info("PERCPU: limit reached, disable warning\n");
+ }
return NULL;
}
@@ -1347,6 +1367,10 @@ struct pcpu_alloc_info * __init pcpu_build_alloc_info(
struct pcpu_alloc_info *ai;
unsigned int *cpu_map;
+ /* this function may be called multiple times */
+ memset(group_map, 0, sizeof(group_map));
+ memset(group_cnt, 0, sizeof(group_map));
+
/*
* Determine min_unit_size, alloc_size and max_upa such that
* alloc_size is multiple of atom_size and is the smallest
@@ -1574,6 +1598,7 @@ static void pcpu_dump_alloc_info(const char *lvl,
int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
void *base_addr)
{
+ static char cpus_buf[4096] __initdata;
static int smap[2], dmap[2];
size_t dyn_size = ai->dyn_size;
size_t size_sum = ai->static_size + ai->reserved_size + dyn_size;
@@ -1585,17 +1610,26 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
int *unit_map;
int group, unit, i;
+ cpumask_scnprintf(cpus_buf, sizeof(cpus_buf), cpu_possible_mask);
+
+#define PCPU_SETUP_BUG_ON(cond) do { \
+ if (unlikely(cond)) { \
+ pr_emerg("PERCPU: failed to initialize, %s", #cond); \
+ pr_emerg("PERCPU: cpu_possible_mask=%s\n", cpus_buf); \
+ pcpu_dump_alloc_info(KERN_EMERG, ai); \
+ BUG(); \
+ } \
+} while (0)
+
/* sanity checks */
BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC ||
ARRAY_SIZE(dmap) >= PCPU_DFL_MAP_ALLOC);
- BUG_ON(ai->nr_groups <= 0);
- BUG_ON(!ai->static_size);
- BUG_ON(!base_addr);
- BUG_ON(ai->unit_size < size_sum);
- BUG_ON(ai->unit_size & ~PAGE_MASK);
- BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
-
- pcpu_dump_alloc_info(KERN_DEBUG, ai);
+ PCPU_SETUP_BUG_ON(ai->nr_groups <= 0);
+ PCPU_SETUP_BUG_ON(!ai->static_size);
+ PCPU_SETUP_BUG_ON(!base_addr);
+ PCPU_SETUP_BUG_ON(ai->unit_size < size_sum);
+ PCPU_SETUP_BUG_ON(ai->unit_size & ~PAGE_MASK);
+ PCPU_SETUP_BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
/* process group information and build config tables accordingly */
group_offsets = alloc_bootmem(ai->nr_groups * sizeof(group_offsets[0]));
@@ -1604,7 +1638,7 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
unit_off = alloc_bootmem(nr_cpu_ids * sizeof(unit_off[0]));
for (cpu = 0; cpu < nr_cpu_ids; cpu++)
- unit_map[cpu] = NR_CPUS;
+ unit_map[cpu] = UINT_MAX;
pcpu_first_unit_cpu = NR_CPUS;
for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
@@ -1618,8 +1652,9 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
if (cpu == NR_CPUS)
continue;
- BUG_ON(cpu > nr_cpu_ids || !cpu_possible(cpu));
- BUG_ON(unit_map[cpu] != NR_CPUS);
+ PCPU_SETUP_BUG_ON(cpu > nr_cpu_ids);
+ PCPU_SETUP_BUG_ON(!cpu_possible(cpu));
+ PCPU_SETUP_BUG_ON(unit_map[cpu] != UINT_MAX);
unit_map[cpu] = unit + i;
unit_off[cpu] = gi->base_offset + i * ai->unit_size;
@@ -1632,7 +1667,11 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
pcpu_nr_units = unit;
for_each_possible_cpu(cpu)
- BUG_ON(unit_map[cpu] == NR_CPUS);
+ PCPU_SETUP_BUG_ON(unit_map[cpu] == UINT_MAX);
+
+ /* we're done parsing the input, undefine BUG macro and dump config */
+#undef PCPU_SETUP_BUG_ON
+ pcpu_dump_alloc_info(KERN_INFO, ai);
pcpu_nr_groups = ai->nr_groups;
pcpu_group_offsets = group_offsets;
@@ -1782,7 +1821,7 @@ int __init pcpu_embed_first_chunk(size_t reserved_size, ssize_t dyn_size,
void *base = (void *)ULONG_MAX;
void **areas = NULL;
struct pcpu_alloc_info *ai;
- size_t size_sum, areas_size;
+ size_t size_sum, areas_size, max_distance;
int group, i, rc;
ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size,
@@ -1832,8 +1871,25 @@ int __init pcpu_embed_first_chunk(size_t reserved_size, ssize_t dyn_size,
}
/* base address is now known, determine group base offsets */
- for (group = 0; group < ai->nr_groups; group++)
+ max_distance = 0;
+ for (group = 0; group < ai->nr_groups; group++) {
ai->groups[group].base_offset = areas[group] - base;
+ max_distance = max_t(size_t, max_distance,
+ ai->groups[group].base_offset);
+ }
+ max_distance += ai->unit_size;
+
+ /* warn if maximum distance is further than 75% of vmalloc space */
+ if (max_distance > (VMALLOC_END - VMALLOC_START) * 3 / 4) {
+ pr_warning("PERCPU: max_distance=0x%zx too large for vmalloc "
+ "space 0x%lx\n",
+ max_distance, VMALLOC_END - VMALLOC_START);
+#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
+ /* and fail if we have fallback */
+ rc = -EINVAL;
+ goto out_free;
+#endif
+ }
pr_info("PERCPU: Embedded %zu pages/cpu @%p s%zu r%zu d%zu u%zu\n",
PFN_DOWN(size_sum), base, ai->static_size, ai->reserved_size,
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-03 12:28:56 +0000