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>hifive-unleashed-5.1
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934acce3c0
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fb0fec501f
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@ -48,6 +48,12 @@ static sector_t map_swap_entry(swp_entry_t, struct block_device**);
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DEFINE_SPINLOCK(swap_lock);
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DEFINE_SPINLOCK(swap_lock);
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static unsigned int nr_swapfiles;
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static unsigned int nr_swapfiles;
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atomic_long_t nr_swap_pages;
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atomic_long_t nr_swap_pages;
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/*
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* Some modules use swappable objects and may try to swap them out under
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* memory pressure (via the shrinker). Before doing so, they may wish to
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* check to see if any swap space is available.
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*/
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EXPORT_SYMBOL_GPL(nr_swap_pages);
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/* protected with swap_lock. reading in vm_swap_full() doesn't need lock */
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/* protected with swap_lock. reading in vm_swap_full() doesn't need lock */
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long total_swap_pages;
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long total_swap_pages;
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static int least_priority;
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static int least_priority;
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