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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2015-12-04 15:58:53 +0000 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2016-01-05 11:02:18 +0100 |
| commit | fb0fec501f08a0a83af7a2b25888ec8cebab53b0 (patch) | |
| tree | 82f78ea91951ae741276fad297ab96ea4638a0c7 /mm/swapfile.c | |
| parent | 934acce3c069a3d8b14085957248444145d9ec1b (diff) | |
| download | lwn-fb0fec501f08a0a83af7a2b25888ec8cebab53b0.tar.gz lwn-fb0fec501f08a0a83af7a2b25888ec8cebab53b0.zip | |
mm: Export nr_swap_pages
Some modules, like i915.ko, use swappable objects and may try to swap
them out under memory pressure (via the shrinker). Before doing so, they
want to check using get_nr_swap_pages() to see if any swap space is
available as otherwise they will waste time purging the object from the
device without recovering any memory for the system. This requires the
nr_swap_pages counter to be exported to the modules.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: "Goel, Akash" <akash.goel@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: linux-mm@kvack.org
Link: http://patchwork.freedesktop.org/patch/msgid/1449244734-25733-1-git-send-email-chris@chris-wilson.co.uk
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'mm/swapfile.c')
| -rw-r--r-- | mm/swapfile.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c index 58877312cf6b..2d259fdb2347 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -48,6 +48,12 @@ static sector_t map_swap_entry(swp_entry_t, struct block_device**); DEFINE_SPINLOCK(swap_lock); static unsigned int nr_swapfiles; atomic_long_t nr_swap_pages; +/* + * Some modules use swappable objects and may try to swap them out under + * memory pressure (via the shrinker). Before doing so, they may wish to + * check to see if any swap space is available. + */ +EXPORT_SYMBOL_GPL(nr_swap_pages); /* protected with swap_lock. reading in vm_swap_full() doesn't need lock */ long total_swap_pages; static int least_priority; |