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mm/zswap.c: avoid unnecessary copy-in at map time

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The buf mapped via zpool_map_handle() is only used to store compressed
page buffer and there is no information to extract from it. So we could
use ZPOOL_MM_WO instead to avoid unnecessary copy-in at map time.

Link: https://lkml.kernel.org/r/20210522092242.3233191-3-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Tian Tao <tiantao6@hisilicon.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Miaohe Lin 2021-06-30 18:52:52 -07:00 committed by Linus Torvalds
parent 2c1e9a2c66
commit ae34af1f11
1 changed files with 1 additions and 1 deletions
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2
mm/zswap.c
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@ -1203,7 +1203,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
zswap_reject_alloc_fail++;
goto put_dstmem;
}
buf = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
buf = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_WO);
memcpy(buf, &zhdr, hlen);
memcpy(buf + hlen, dst, dlen);
zpool_unmap_handle(entry->pool->zpool, handle);