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authorMiaohe Lin <linmiaohe@huawei.com>2021-06-30 18:52:52 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-06-30 20:47:31 -0700
commitae34af1f11d0a6ae849b7605d15df9798dab7b46 (patch)
treefb7b66c2d0f61e59121cbf7609c2f9a6f1251e87
parent2c1e9a2c668b4606e9c27fe420ddf83d113928c8 (diff)
downloadlinux-ae34af1f11d0a6ae849b7605d15df9798dab7b46.tar.bz2
mm/zswap.c: avoid unnecessary copy-in at map time
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>
-rw-r--r--mm/zswap.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/zswap.c b/mm/zswap.c
index e93459319fdb..c27ce9f2cdf8 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -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);