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-rw-r--r--mm/frontswap.c150
1 files changed, 90 insertions, 60 deletions
diff --git a/mm/frontswap.c b/mm/frontswap.c
index e25025574a0..6b3e71a2cd4 100644
--- a/mm/frontswap.c
+++ b/mm/frontswap.c
@@ -11,15 +11,11 @@
* This work is licensed under the terms of the GNU GPL, version 2.
*/
-#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/swap.h>
#include <linux/swapops.h>
-#include <linux/proc_fs.h>
#include <linux/security.h>
-#include <linux/capability.h>
#include <linux/module.h>
-#include <linux/uaccess.h>
#include <linux/debugfs.h>
#include <linux/frontswap.h>
#include <linux/swapfile.h>
@@ -110,16 +106,21 @@ void __frontswap_init(unsigned type)
BUG_ON(sis == NULL);
if (sis->frontswap_map == NULL)
return;
- if (frontswap_enabled)
- (*frontswap_ops.init)(type);
+ frontswap_ops.init(type);
}
EXPORT_SYMBOL(__frontswap_init);
+static inline void __frontswap_clear(struct swap_info_struct *sis, pgoff_t offset)
+{
+ frontswap_clear(sis, offset);
+ atomic_dec(&sis->frontswap_pages);
+}
+
/*
* "Store" data from a page to frontswap and associate it with the page's
* swaptype and offset. Page must be locked and in the swap cache.
* If frontswap already contains a page with matching swaptype and
- * offset, the frontswap implmentation may either overwrite the data and
+ * offset, the frontswap implementation may either overwrite the data and
* return success or invalidate the page from frontswap and return failure.
*/
int __frontswap_store(struct page *page)
@@ -134,22 +135,21 @@ int __frontswap_store(struct page *page)
BUG_ON(sis == NULL);
if (frontswap_test(sis, offset))
dup = 1;
- ret = (*frontswap_ops.store)(type, offset, page);
+ ret = frontswap_ops.store(type, offset, page);
if (ret == 0) {
frontswap_set(sis, offset);
inc_frontswap_succ_stores();
if (!dup)
atomic_inc(&sis->frontswap_pages);
- } else if (dup) {
+ } else {
/*
failed dup always results in automatic invalidate of
the (older) page from frontswap
*/
- frontswap_clear(sis, offset);
- atomic_dec(&sis->frontswap_pages);
- inc_frontswap_failed_stores();
- } else
inc_frontswap_failed_stores();
+ if (dup)
+ __frontswap_clear(sis, offset);
+ }
if (frontswap_writethrough_enabled)
/* report failure so swap also writes to swap device */
ret = -1;
@@ -173,7 +173,7 @@ int __frontswap_load(struct page *page)
BUG_ON(!PageLocked(page));
BUG_ON(sis == NULL);
if (frontswap_test(sis, offset))
- ret = (*frontswap_ops.load)(type, offset, page);
+ ret = frontswap_ops.load(type, offset, page);
if (ret == 0)
inc_frontswap_loads();
return ret;
@@ -190,9 +190,8 @@ void __frontswap_invalidate_page(unsigned type, pgoff_t offset)
BUG_ON(sis == NULL);
if (frontswap_test(sis, offset)) {
- (*frontswap_ops.invalidate_page)(type, offset);
- atomic_dec(&sis->frontswap_pages);
- frontswap_clear(sis, offset);
+ frontswap_ops.invalidate_page(type, offset);
+ __frontswap_clear(sis, offset);
inc_frontswap_invalidates();
}
}
@@ -209,67 +208,102 @@ void __frontswap_invalidate_area(unsigned type)
BUG_ON(sis == NULL);
if (sis->frontswap_map == NULL)
return;
- (*frontswap_ops.invalidate_area)(type);
+ frontswap_ops.invalidate_area(type);
atomic_set(&sis->frontswap_pages, 0);
memset(sis->frontswap_map, 0, sis->max / sizeof(long));
}
EXPORT_SYMBOL(__frontswap_invalidate_area);
-/*
- * Frontswap, like a true swap device, may unnecessarily retain pages
- * under certain circumstances; "shrink" frontswap is essentially a
- * "partial swapoff" and works by calling try_to_unuse to attempt to
- * unuse enough frontswap pages to attempt to -- subject to memory
- * constraints -- reduce the number of pages in frontswap to the
- * number given in the parameter target_pages.
- */
-void frontswap_shrink(unsigned long target_pages)
+static unsigned long __frontswap_curr_pages(void)
{
- struct swap_info_struct *si = NULL;
- int si_frontswap_pages;
- unsigned long total_pages = 0, total_pages_to_unuse;
- unsigned long pages = 0, pages_to_unuse = 0;
int type;
- bool locked = false;
+ unsigned long totalpages = 0;
+ struct swap_info_struct *si = NULL;
- /*
- * we don't want to hold swap_lock while doing a very
- * lengthy try_to_unuse, but swap_list may change
- * so restart scan from swap_list.head each time
- */
- spin_lock(&swap_lock);
- locked = true;
- total_pages = 0;
+ assert_spin_locked(&swap_lock);
for (type = swap_list.head; type >= 0; type = si->next) {
si = swap_info[type];
- total_pages += atomic_read(&si->frontswap_pages);
+ totalpages += atomic_read(&si->frontswap_pages);
}
- if (total_pages <= target_pages)
- goto out;
- total_pages_to_unuse = total_pages - target_pages;
+ return totalpages;
+}
+
+static int __frontswap_unuse_pages(unsigned long total, unsigned long *unused,
+ int *swapid)
+{
+ int ret = -EINVAL;
+ struct swap_info_struct *si = NULL;
+ int si_frontswap_pages;
+ unsigned long total_pages_to_unuse = total;
+ unsigned long pages = 0, pages_to_unuse = 0;
+ int type;
+
+ assert_spin_locked(&swap_lock);
for (type = swap_list.head; type >= 0; type = si->next) {
si = swap_info[type];
si_frontswap_pages = atomic_read(&si->frontswap_pages);
- if (total_pages_to_unuse < si_frontswap_pages)
+ if (total_pages_to_unuse < si_frontswap_pages) {
pages = pages_to_unuse = total_pages_to_unuse;
- else {
+ } else {
pages = si_frontswap_pages;
pages_to_unuse = 0; /* unuse all */
}
/* ensure there is enough RAM to fetch pages from frontswap */
- if (security_vm_enough_memory_mm(current->mm, pages))
+ if (security_vm_enough_memory_mm(current->mm, pages)) {
+ ret = -ENOMEM;
continue;
+ }
vm_unacct_memory(pages);
+ *unused = pages_to_unuse;
+ *swapid = type;
+ ret = 0;
break;
}
- if (type < 0)
- goto out;
- locked = false;
+
+ return ret;
+}
+
+static int __frontswap_shrink(unsigned long target_pages,
+ unsigned long *pages_to_unuse,
+ int *type)
+{
+ unsigned long total_pages = 0, total_pages_to_unuse;
+
+ assert_spin_locked(&swap_lock);
+
+ total_pages = __frontswap_curr_pages();
+ if (total_pages <= target_pages) {
+ /* Nothing to do */
+ *pages_to_unuse = 0;
+ return 0;
+ }
+ total_pages_to_unuse = total_pages - target_pages;
+ return __frontswap_unuse_pages(total_pages_to_unuse, pages_to_unuse, type);
+}
+
+/*
+ * Frontswap, like a true swap device, may unnecessarily retain pages
+ * under certain circumstances; "shrink" frontswap is essentially a
+ * "partial swapoff" and works by calling try_to_unuse to attempt to
+ * unuse enough frontswap pages to attempt to -- subject to memory
+ * constraints -- reduce the number of pages in frontswap to the
+ * number given in the parameter target_pages.
+ */
+void frontswap_shrink(unsigned long target_pages)
+{
+ unsigned long pages_to_unuse = 0;
+ int type, ret;
+
+ /*
+ * we don't want to hold swap_lock while doing a very
+ * lengthy try_to_unuse, but swap_list may change
+ * so restart scan from swap_list.head each time
+ */
+ spin_lock(&swap_lock);
+ ret = __frontswap_shrink(target_pages, &pages_to_unuse, &type);
spin_unlock(&swap_lock);
- try_to_unuse(type, true, pages_to_unuse);
-out:
- if (locked)
- spin_unlock(&swap_lock);
+ if (ret == 0 && pages_to_unuse)
+ try_to_unuse(type, true, pages_to_unuse);
return;
}
EXPORT_SYMBOL(frontswap_shrink);
@@ -281,16 +315,12 @@ EXPORT_SYMBOL(frontswap_shrink);
*/
unsigned long frontswap_curr_pages(void)
{
- int type;
unsigned long totalpages = 0;
- struct swap_info_struct *si = NULL;
spin_lock(&swap_lock);
- for (type = swap_list.head; type >= 0; type = si->next) {
- si = swap_info[type];
- totalpages += atomic_read(&si->frontswap_pages);
- }
+ totalpages = __frontswap_curr_pages();
spin_unlock(&swap_lock);
+
return totalpages;
}
EXPORT_SYMBOL(frontswap_curr_pages);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-01 22:32:26 +0000