The patch titled
Subject: mm/zswap: remove the memcpy if acomp is not sleepable
has been added to the -mm mm-unstable branch. Its filename is
mm-zswap-remove-the-memcpy-if-acomp-is-not-sleepable.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-zswap-remove-the-memcpy-if-acomp-is-not-sleepable.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Barry Song <v-songbaohua@xxxxxxxx>
Subject: mm/zswap: remove the memcpy if acomp is not sleepable
Date: Sat, 17 Feb 2024 17:51:01 +1300
Most compressors are actually CPU-based and won't sleep during compression
and decompression. We should remove the redundant memcpy for them.
Link: https://lkml.kernel.org/r/20240217045102.55339-3-21cnbao@xxxxxxxxx
Signed-off-by: Barry Song <v-songbaohua@xxxxxxxx>
Tested-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
Reviewed-by: Nhat Pham <nphamcs@xxxxxxxxx>
Acked-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Reviewed-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
Cc: Chris Li <chrisl@xxxxxxxxxx>
Cc: Dan Streetman <ddstreet@xxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Seth Jennings <sjenning@xxxxxxxxxx>
Cc: Vitaly Wool <vitaly.wool@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/zswap.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/mm/zswap.c~mm-zswap-remove-the-memcpy-if-acomp-is-not-sleepable
+++ a/mm/zswap.c
@@ -162,6 +162,7 @@ struct crypto_acomp_ctx {
struct crypto_wait wait;
u8 *buffer;
struct mutex mutex;
+ bool is_sleepable;
};
/*
@@ -973,6 +974,7 @@ static int zswap_cpu_comp_prepare(unsign
goto acomp_fail;
}
acomp_ctx->acomp = acomp;
+ acomp_ctx->is_sleepable = acomp_is_sleepable(acomp);
req = acomp_request_alloc(acomp_ctx->acomp);
if (!req) {
@@ -1101,7 +1103,7 @@ static void zswap_decompress(struct zswa
mutex_lock(&acomp_ctx->mutex);
src = zpool_map_handle(zpool, entry->handle, ZPOOL_MM_RO);
- if (!zpool_can_sleep_mapped(zpool)) {
+ if (acomp_ctx->is_sleepable && !zpool_can_sleep_mapped(zpool)) {
memcpy(acomp_ctx->buffer, src, entry->length);
src = acomp_ctx->buffer;
zpool_unmap_handle(zpool, entry->handle);
@@ -1115,7 +1117,7 @@ static void zswap_decompress(struct zswa
BUG_ON(acomp_ctx->req->dlen != PAGE_SIZE);
mutex_unlock(&acomp_ctx->mutex);
- if (zpool_can_sleep_mapped(zpool))
+ if (!acomp_ctx->is_sleepable || zpool_can_sleep_mapped(zpool))
zpool_unmap_handle(zpool, entry->handle);
}
_
Patches currently in -mm which might be from v-songbaohua@xxxxxxxx are
zram-do-not-allocate-physically-contiguous-strm-buffers.patch
crypto-introduce-acomp_is_sleepable-to-expose-if-comp-drivers-might-sleep.patch
mm-zswap-remove-the-memcpy-if-acomp-is-not-sleepable.patch
crypto-scompress-remove-memcpy-if-sg_nents-is-1.patch
