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mm: zsmalloc: return -ENOSPC rather than -EINVAL in zs_malloc while size is too large

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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@oppo.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
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>
This commit is contained in:
Barry Song 2023-12-28 19:18:02 +13:00 committed by Andrew Morton
parent c701123bd6
commit fc8580edba
1 changed files with 4 additions and 1 deletions
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5
mm/zsmalloc.c
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@ -1364,9 +1364,12 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp)
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);