From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Waiman Long <longman@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Petr Mladek <pmladek@suse.com>,
Steven Rostedt <rostedt@goodmis.org>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
linux-mm@kvack.org, Ira Weiny <ira.weiny@intel.com>,
Rafael Aquini <aquini@redhat.com>
Subject: Re: [PATCH v2 1/3] lib/vsprintf: Avoid redundant work with 0 size
Date: Mon, 31 Jan 2022 11:53:40 +0900 [thread overview]
Message-ID: <YfdPNPCjSZ5WI9+4@google.com> (raw)
In-Reply-To: <20220129205315.478628-2-longman@redhat.com>
On (22/01/29 15:53), Waiman Long wrote:
> For *scnprintf(), vsnprintf() is always called even if the input size is
> 0. That is a waste of time, so just return 0 in this case.
>
> Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> +++ b/lib/vsprintf.c
> @@ -2895,13 +2895,15 @@ int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
> {
> int i;
>
> + if (!size)
> + return 0;
> +
> i = vsnprintf(buf, size, fmt, args);
>
> if (likely(i < size))
> return i;
> - if (size != 0)
> - return size - 1;
> - return 0;
> +
> + return size - 1;
> }
> EXPORT_SYMBOL(vscnprintf);
next prev parent reply other threads:[~2022-01-31 2:54 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-29 20:53 [PATCH v2 0/3] mm/page_owner: Extend page_owner to show memcg information Waiman Long
2022-01-29 20:53 ` [PATCH v2 1/3] lib/vsprintf: Avoid redundant work with 0 size Waiman Long
2022-01-30 20:49 ` David Rientjes
2022-01-30 20:57 ` Waiman Long
2022-01-31 10:25 ` Andy Shevchenko
2022-01-31 10:30 ` Andy Shevchenko
2022-01-31 10:34 ` Andy Shevchenko
2022-01-31 11:02 ` Rasmus Villemoes
2022-01-31 11:22 ` Andy Shevchenko
2022-01-31 18:48 ` Waiman Long
2022-02-01 7:12 ` Rasmus Villemoes
2022-02-01 16:01 ` Waiman Long
2022-01-31 2:53 ` Sergey Senozhatsky [this message]
2022-01-31 18:17 ` Roman Gushchin
2022-01-29 20:53 ` [PATCH v2 2/3] mm/page_owner: Use scnprintf() to avoid excessive buffer overrun check Waiman Long
2022-01-31 2:58 ` Sergey Senozhatsky
2022-01-29 20:53 ` [PATCH v2 3/3] mm/page_owner: Dump memcg information Waiman Long
2022-01-30 6:33 ` Mike Rapoport
2022-01-30 18:22 ` Waiman Long
2022-01-30 20:51 ` David Rientjes
2022-01-31 9:38 ` Michal Hocko
2022-01-31 16:53 ` Johannes Weiner
2022-01-31 18:15 ` Roman Gushchin
2022-01-31 18:25 ` Michal Hocko
2022-01-31 18:38 ` Waiman Long
2022-02-01 10:49 ` Michal Hocko
2022-02-01 16:41 ` Waiman Long
2022-02-02 8:57 ` Michal Hocko
2022-02-02 15:54 ` Roman Gushchin
2022-02-02 16:38 ` Michal Hocko
2022-02-02 17:51 ` Roman Gushchin
2022-02-02 17:56 ` Michal Hocko
2022-02-02 16:29 ` Waiman Long
2022-01-31 19:01 ` Waiman Long
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