Commit 8d9b6370 authored by Sergey Senozhatsky's avatar Sergey Senozhatsky Committed by Andrew Morton
Browse files

zswap: do not allocate from atomic pool 

zswap_frontswap_load() should be called from preemptible context (we even
call mutex_lock() there) and it does not look like we need to do
GFP_ATOMIC allocaion for temp buffer.  The same applies to
zswap_writeback_entry().

Use GFP_KERNEL for temporary buffer allocation in both cases.

Link: https://lkml.kernel.org/r/Y3xCTr6ikbtcUr/y@google.com


Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Signed-off-by: default avatarNhat Pham <nphamcs@gmail.com>
Signed-off-by: default avatarSergey Senozhatsky <senozhatsky@chromium.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 7ce5f7e1

mm/zpool.c

+7 −0
Original line number Diff line number Diff line
@@ -387,6 +387,13 @@ bool zpool_evictable(struct zpool *zpool) 
 * zpool_can_sleep_mapped - Test if zpool can sleep when do mapped.

 * @zpool:	The zpool to test

 *

 * Some allocators enter non-preemptible context in ->map() callback (e.g.

 * disable pagefaults) and exit that context in ->unmap(), which limits what

 * we can do with the mapped object. For instance, we cannot wait for

 * asynchronous crypto API to decompress such an object or take mutexes

 * since those will call into the scheduler. This function tells us whether

 * we use such an allocator.

 *

 * Returns: true if zpool can sleep; false otherwise.

 */

bool zpool_can_sleep_mapped(struct zpool *zpool)

mm/zswap.c

+2 −2
Original line number Diff line number Diff line
@@ -958,7 +958,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle) 
	};



	if (!zpool_can_sleep_mapped(pool)) {

		tmp = kmalloc(PAGE_SIZE, GFP_ATOMIC);

		tmp = kmalloc(PAGE_SIZE, GFP_KERNEL);

		if (!tmp)

			return -ENOMEM;

	}
@@ -1311,7 +1311,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset, 
	}



	if (!zpool_can_sleep_mapped(entry->pool->zpool)) {

		tmp = kmalloc(entry->length, GFP_ATOMIC);

		tmp = kmalloc(entry->length, GFP_KERNEL);

		if (!tmp) {

			ret = -ENOMEM;

			goto freeentry;