The patch titled
Subject: mm: zsmalloc: return -ENOSPC rather than -EINVAL in zs_malloc while size is too large
has been added to the -mm mm-unstable branch. Its filename is
mm-zsmalloc-return-enospc-rather-than-einval-in-zs_malloc-while-size-is-too-large.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-zsmalloc-return-enospc-rather-than-einval-in-zs_malloc-while-size-is-too-large.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 <21cnbao@xxxxxxxxx>
Subject: mm: zsmalloc: return -ENOSPC rather than -EINVAL in zs_malloc while size is too large
Date: Thu, 28 Dec 2023 19:18:02 +1300
This is the case the "compressed" data is larger than the original data,
it is better to return -ENOSPC which can help zswap record a poor compr
rather than an invalid request. Then we get more friendly counting for
reject_compress_poor in debugfs.
bool zswap_store(struct folio *folio)
{
...
ret = zpool_malloc(zpool, dlen, gfp, &handle);
if (ret == -ENOSPC) {
zswap_reject_compress_poor++;
goto put_dstmem;
}
if (ret) {
zswap_reject_alloc_fail++;
goto put_dstmem;
}
...
}
Also, zbud_alloc() and z3fold_alloc() are returning ENOSPC in the same
case, eg
static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp,
unsigned long *handle)
{
...
if (!size || (gfp & __GFP_HIGHMEM))
return -EINVAL;
if (size > PAGE_SIZE)
return -ENOSPC;
...
}
Link: https://lkml.kernel.org/r/20231228061802.25280-1-v-songbaohua@xxxxxxxx
Signed-off-by: Barry Song <v-songbaohua@xxxxxxxx>
Reviewed-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
Cc: Chris Li <chrisl@xxxxxxxxxx>
Cc: Dan Streetman <ddstreet@xxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Nhat Pham <nphamcs@xxxxxxxxx>
Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Seth Jennings <sjenning@xxxxxxxxxx>
Cc: Vitaly Wool <vitaly.wool@xxxxxxxxxxxx>
Cc: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/zsmalloc.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/mm/zsmalloc.c~mm-zsmalloc-return-enospc-rather-than-einval-in-zs_malloc-while-size-is-too-large
+++ a/mm/zsmalloc.c
@@ -1364,9 +1364,12 @@ unsigned long zs_malloc(struct zs_pool *
int newfg;
struct zspage *zspage;
- if (unlikely(!size || size > ZS_MAX_ALLOC_SIZE))
+ if (unlikely(!size))
return (unsigned long)ERR_PTR(-EINVAL);
+ if (unlikely(size > ZS_MAX_ALLOC_SIZE))
+ return (unsigned long)ERR_PTR(-ENOSPC);
+
handle = cache_alloc_handle(pool, gfp);
if (!handle)
return (unsigned long)ERR_PTR(-ENOMEM);
_
Patches currently in -mm which might be from 21cnbao@xxxxxxxxx are
mm-zsmalloc-return-enospc-rather-than-einval-in-zs_malloc-while-size-is-too-large.patch
