From: Ganesh Mahendran <opensource.ganesh@gmail.com>
To: Dan Streetman <ddstreet@ieee.org>
Cc: Minchan Kim <minchan@kernel.org>, Nitin Gupta <ngupta@vflare.org>,
Andrew Morton <akpm@linux-foundation.org>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Seth Jennings <sjenning@redhat.com>, Yu Zhao <yuzhao@google.com>,
Linux-MM <linux-mm@kvack.org>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
Dan Streetman <dan.streetman@canonical.com>
Subject: Re: [PATCH] mm/zsmalloc: don't fail if can't create debugfs info
Date: Tue, 3 May 2016 10:18:01 +0800 [thread overview]
Message-ID: <CADAEsF-kaCQnNN_9gySw3J0UT4mGh8KFp75tGSJtaDAuN1T10A@mail.gmail.com> (raw)
In-Reply-To: <1461857808-11030-1-git-send-email-ddstreet@ieee.org>
Hello, Dan:
2016-04-28 23:36 GMT+08:00 Dan Streetman <ddstreet@ieee.org>:
> Change the return type of zs_pool_stat_create() to void, and
> remove the logic to abort pool creation if the stat debugfs
> dir/file could not be created.
>
> The debugfs stat file is for debugging/information only, and doesn't
> affect operation of zsmalloc; there is no reason to abort creating
> the pool if the stat file can't be created. This was seen with
> zswap, which used the same name for all pool creations, which caused
> zsmalloc to fail to create a second pool for zswap if
> CONFIG_ZSMALLOC_STAT was enabled.
>
> Cc: Dan Streetman <dan.streetman@canonical.com>
> Signed-off-by: Dan Streetman <ddstreet@ieee.org>
> ---
> mm/zsmalloc.c | 17 +++++++----------
> 1 file changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> index e72efb1..25a7db2 100644
> --- a/mm/zsmalloc.c
> +++ b/mm/zsmalloc.c
> @@ -567,17 +567,17 @@ static const struct file_operations zs_stat_size_ops = {
> .release = single_release,
> };
>
> -static int zs_pool_stat_create(const char *name, struct zs_pool *pool)
> +static void zs_pool_stat_create(const char *name, struct zs_pool *pool)
> {
> struct dentry *entry;
>
> if (!zs_stat_root)
> - return -ENODEV;
> + return;
Since the error will not be propagated, Would it be better if you
add some pr_warn information here(also in zs_stat_init() if you
send your V2 patch as Minchan suggested)? It will be useful for
developers to know the reason of failed to create debugfs file/dir.
Thanks.
>
> entry = debugfs_create_dir(name, zs_stat_root);
> if (!entry) {
> pr_warn("debugfs dir <%s> creation failed\n", name);
> - return -ENOMEM;
> + return;
> }
> pool->stat_dentry = entry;
>
> @@ -586,10 +586,8 @@ static int zs_pool_stat_create(const char *name, struct zs_pool *pool)
> if (!entry) {
> pr_warn("%s: debugfs file entry <%s> creation failed\n",
> name, "classes");
> - return -ENOMEM;
> + return;
> }
> -
> - return 0;
> }
>
> static void zs_pool_stat_destroy(struct zs_pool *pool)
> @@ -607,9 +605,8 @@ static void __exit zs_stat_exit(void)
> {
> }
>
> -static inline int zs_pool_stat_create(const char *name, struct zs_pool *pool)
> +static inline void zs_pool_stat_create(const char *name, struct zs_pool *pool)
> {
> - return 0;
> }
>
> static inline void zs_pool_stat_destroy(struct zs_pool *pool)
> @@ -1956,8 +1953,8 @@ struct zs_pool *zs_create_pool(const char *name, gfp_t flags)
>
> pool->flags = flags;
>
> - if (zs_pool_stat_create(name, pool))
> - goto err;
> + /* debug only, don't abort if it fails */
> + zs_pool_stat_create(name, pool);
>
> /*
> * Not critical, we still can use the pool
> --
> 2.7.4
>
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next prev parent reply other threads:[~2016-05-03 2:18 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-28 15:36 [PATCH] mm/zsmalloc: don't fail if can't create debugfs info Dan Streetman
2016-04-28 22:07 ` Andrew Morton
2016-04-29 0:38 ` Sergey Senozhatsky
2016-04-29 5:37 ` Minchan Kim
2016-04-29 14:50 ` Dan Streetman
2016-04-29 15:33 ` Minchan Kim
2016-05-03 2:18 ` Ganesh Mahendran [this message]
2016-05-19 15:18 ` [PATCHv2] " Dan Streetman
2016-05-20 2:33 ` Ganesh Mahendran
2016-05-20 4:08 ` Sergey Senozhatsky
2016-05-20 10:32 ` Dan Streetman
2016-05-23 3:03 ` Minchan Kim
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