diff options
| -rw-r--r-- | include/linux/frontswap.h | 2 | ||||
| -rw-r--r-- | mm/frontswap.c | 34 |
2 files changed, 32 insertions, 4 deletions
diff --git a/include/linux/frontswap.h b/include/linux/frontswap.h index 0e4e2eec5c1d..30442547b9e6 100644 --- a/include/linux/frontswap.h +++ b/include/linux/frontswap.h @@ -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); diff --git a/mm/frontswap.c b/mm/frontswap.c index 6b3e71a2cd48..2890e67d6026 100644 --- a/mm/frontswap.c +++ b/mm/frontswap.c @@ -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 @@ -97,6 +104,15 @@ 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. */ void __frontswap_init(unsigned type) @@ -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; } |