From: Nhat Pham Date: Tue, 24 Oct 2023 23:45:09 +0000 (-0700) Subject: zswap: export compression failure stats X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=cb61dad80fdc6a8f01b101e823a9335cd6d61071;p=linux.git zswap: export compression failure stats During a zswap store attempt, the compression algorithm could fail (for e.g due to the page containing incompressible random data). This is not tracked in any of existing zswap counters, making it hard to monitor for and investigate. We have run into this problem several times in our internal investigations on zswap store failures. This patch adds a dedicated debugfs counter for compression algorithm failures. Link: https://lkml.kernel.org/r/20231024234509.2680539-1-nphamcs@gmail.com Signed-off-by: Nhat Pham Reviewed-by: Sergey Senozhatsky Cc: Dan Streetman Cc: Domenico Cerasuolo Cc: Johannes Weiner Cc: Michal Hocko Cc: Muchun Song Cc: Roman Gushchin Cc: Seth Jennings Cc: Shakeel Butt Cc: Vitaly Wool Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- diff --git a/mm/zswap.c b/mm/zswap.c index 060857adca76b..74411dfdad925 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -62,6 +62,8 @@ static u64 zswap_pool_limit_hit; static u64 zswap_written_back_pages; /* Store failed due to a reclaim failure after pool limit was reached */ static u64 zswap_reject_reclaim_fail; +/* Store failed due to compression algorithm failure */ +static u64 zswap_reject_compress_fail; /* Compressed page was too big for the allocator to (optimally) store */ static u64 zswap_reject_compress_poor; /* Store failed because underlying allocator could not get memory */ @@ -1312,8 +1314,10 @@ bool zswap_store(struct folio *folio) ret = crypto_wait_req(crypto_acomp_compress(acomp_ctx->req), &acomp_ctx->wait); dlen = acomp_ctx->req->dlen; - if (ret) + if (ret) { + zswap_reject_compress_fail++; goto put_dstmem; + } /* store */ zpool = zswap_find_zpool(entry); @@ -1553,6 +1557,8 @@ static int zswap_debugfs_init(void) zswap_debugfs_root, &zswap_reject_alloc_fail); debugfs_create_u64("reject_kmemcache_fail", 0444, zswap_debugfs_root, &zswap_reject_kmemcache_fail); + debugfs_create_u64("reject_compress_fail", 0444, + zswap_debugfs_root, &zswap_reject_compress_fail); debugfs_create_u64("reject_compress_poor", 0444, zswap_debugfs_root, &zswap_reject_compress_poor); debugfs_create_u64("written_back_pages", 0444,