+ mm-zswap-change-dstmem-size-to-one-page.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/zswap: change dstmem size to one page
has been added to the -mm mm-unstable branch.  Its filename is
     mm-zswap-change-dstmem-size-to-one-page.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-zswap-change-dstmem-size-to-one-page.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: Chengming Zhou <zhouchengming@bytedance.com>
Subject: mm/zswap: change dstmem size to one page
Date: Wed, 13 Dec 2023 04:17:59 +0000

Change the dstmem size from 2 * PAGE_SIZE to only one page since we only
need at most one page when compress, and the "dlen" is also PAGE_SIZE in
acomp_request_set_params().  If the output size > PAGE_SIZE we don't wanna
store the output in zswap anyway.

So change it to one page, and delete the stale comment.

Link: https://lkml.kernel.org/r/20231213-zswap-dstmem-v1-2-896763369d04@bytedance.com
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Chris Li <chriscli@google.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/zswap.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

--- a/mm/zswap.c~mm-zswap-change-dstmem-size-to-one-page
+++ a/mm/zswap.c
@@ -707,7 +707,7 @@ static int zswap_dstmem_prepare(unsigned
 	struct mutex *mutex;
 	u8 *dst;
 
-	dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
+	dst = kmalloc_node(PAGE_SIZE, GFP_KERNEL, cpu_to_node(cpu));
 	if (!dst)
 		return -ENOMEM;
 
@@ -1657,8 +1657,7 @@ bool zswap_store(struct folio *folio)
 	sg_init_table(&input, 1);
 	sg_set_page(&input, page, PAGE_SIZE, 0);
 
-	/* zswap_dstmem is of size (PAGE_SIZE * 2). Reflect same in sg_list */
-	sg_init_one(&output, dst, PAGE_SIZE * 2);
+	sg_init_one(&output, dst, PAGE_SIZE);
 	acomp_request_set_params(acomp_ctx->req, &input, &output, PAGE_SIZE, dlen);
 	/*
 	 * it maybe looks a little bit silly that we send an asynchronous request,
_

Patches currently in -mm which might be from zhouchengming@bytedance.com are

mm-zswap-reuse-dstmem-when-decompress.patch
mm-zswap-change-dstmem-size-to-one-page.patch
mm-zswap-refactor-out-__zswap_load.patch
mm-zswap-cleanup-zswap_load.patch
mm-zswap-cleanup-zswap_reclaim_entry.patch