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Features:

Browse Source 
* Support exlusive get if backend is capable.
 Bug-fixes:
  * Fix compile warnings
  * Add comments/cleanup doc
  * Fix wrong if condition
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Merge tag 'stable/for-linus-3.7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/mm

Pull frontswap update from Konrad Rzeszutek Wilk:
 "Features:
   - Support exlusive get if backend is capable.
  Bug-fixes:
   - Fix compile warnings
   - Add comments/cleanup doc
   - Fix wrong if condition"

* tag 'stable/for-linus-3.7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/mm:
  frontswap: support exclusive gets if tmem backend is capable
  mm: frontswap: fix a wrong if condition in frontswap_shrink
  mm/frontswap: fix uninit'ed variable warning
  mm/frontswap: cleanup doc and comment error
  mm: frontswap: remove unneeded headers
This commit is contained in:
Linus Torvalds 2012-10-02 22:08:14 -07:00
commit 33c2a17412
2 changed files with 32 additions and 4 deletions
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2
include/linux/frontswap.h
View File

@ -19,6 +19,8 @@ extern struct frontswap_ops
extern void frontswap_shrink(unsigned long);
extern unsigned long frontswap_curr_pages(void);
extern void frontswap_writethrough(bool);
#define FRONTSWAP_HAS_EXCLUSIVE_GETS
extern void frontswap_tmem_exclusive_gets(bool);
extern void __frontswap_init(unsigned type);
extern int __frontswap_store(struct page *page);

34
mm/frontswap.c
View File

@ -44,6 +44,13 @@ EXPORT_SYMBOL(frontswap_enabled);
*/
static bool frontswap_writethrough_enabled __read_mostly;
/*
* If enabled, the underlying tmem implementation is capable of doing
* exclusive gets, so frontswap_load, on a successful tmem_get must
* mark the page as no longer in frontswap AND mark it dirty.
*/
static bool frontswap_tmem_exclusive_gets_enabled __read_mostly;
#ifdef CONFIG_DEBUG_FS
/*
* Counters available via /sys/kernel/debug/frontswap (if debugfs is
@ -96,6 +103,15 @@ void frontswap_writethrough(bool enable)
}
EXPORT_SYMBOL(frontswap_writethrough);
/*
* Enable/disable frontswap exclusive gets (see above).
*/
void frontswap_tmem_exclusive_gets(bool enable)
{
frontswap_tmem_exclusive_gets_enabled = enable;
}
EXPORT_SYMBOL(frontswap_tmem_exclusive_gets);
/*
* Called when a swap device is swapon'd.
*/
@ -174,8 +190,13 @@ int __frontswap_load(struct page *page)
BUG_ON(sis == NULL);
if (frontswap_test(sis, offset))
ret = frontswap_ops.load(type, offset, page);
if (ret == 0)
if (ret == 0) {
inc_frontswap_loads();
if (frontswap_tmem_exclusive_gets_enabled) {
SetPageDirty(page);
frontswap_clear(sis, offset);
}
}
return ret;
}
EXPORT_SYMBOL(__frontswap_load);
@ -263,6 +284,11 @@ static int __frontswap_unuse_pages(unsigned long total, unsigned long *unused,
return ret;
}
/*
* Used to check if it's necessory and feasible to unuse pages.
* Return 1 when nothing to do, 0 when need to shink pages,
* error code when there is an error.
*/
static int __frontswap_shrink(unsigned long target_pages,
unsigned long *pages_to_unuse,
int *type)
@ -275,7 +301,7 @@ static int __frontswap_shrink(unsigned long target_pages,
if (total_pages <= target_pages) {
/* Nothing to do */
*pages_to_unuse = 0;
return 0;
return 1;
}
total_pages_to_unuse = total_pages - target_pages;
return __frontswap_unuse_pages(total_pages_to_unuse, pages_to_unuse, type);
@ -292,7 +318,7 @@ static int __frontswap_shrink(unsigned long target_pages,
void frontswap_shrink(unsigned long target_pages)
{
unsigned long pages_to_unuse = 0;
int type, ret;
int uninitialized_var(type), ret;
/*
* we don't want to hold swap_lock while doing a very
@ -302,7 +328,7 @@ void frontswap_shrink(unsigned long target_pages)
spin_lock(&swap_lock);
ret = __frontswap_shrink(target_pages, &pages_to_unuse, &type);
spin_unlock(&swap_lock);
if (ret == 0 && pages_to_unuse)
if (ret == 0)
try_to_unuse(type, true, pages_to_unuse);
return;
}