From: Eric Dumazet <eric.dumazet@gmail.com>
To: Changli Gao <xiaosuo@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
Matthew Wilcox <matthew@wil.cx>, Arnd Bergmann <arnd@arndb.de>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org
Subject: Re: [PATCH] fs: add FD_CLOFORK and O_CLOFORK
Date: Sat, 07 May 2011 07:25:45 +0200 [thread overview]
Message-ID: <1304745945.2821.601.camel@edumazet-laptop> (raw)
In-Reply-To: <1304743740-3405-1-git-send-email-xiaosuo@gmail.com>
Le samedi 07 mai 2011 à 12:49 +0800, Changli Gao a écrit :
> If FD_CLOFORK is 1, when a fork occurs, the corresponding file descriptor
> will be closed for the child process. IOW, the file descriptor isn't
> inheritable.
>
> FD_CLOFORK is used as IBM does.
Is it part of a standard, and what could be the use for such thing ?
Why had we wait 2011 to add it in linux ?
>
> O_CLOFORK is also added to avoid the additional fcntl(2) after open(2).
>
> Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Your implementation has some peformance implication.
close_on_exec and close_on_fork bit for a given fd would be on separate
cache lines. So you add a cost on threaded programs for open()/close()
[ Yes, we apparently clear close_on_exec bit in close()... we could let
it untouched and make flush_old_files() aware of that ]
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WARNING: multiple messages have this Message-ID (diff)
From: Eric Dumazet <eric.dumazet@gmail.com>
To: Changli Gao <xiaosuo@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
Matthew Wilcox <matthew@wil.cx>, Arnd Bergmann <arnd@arndb.de>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org
Subject: Re: [PATCH] fs: add FD_CLOFORK and O_CLOFORK
Date: Sat, 07 May 2011 07:25:45 +0200 [thread overview]
Message-ID: <1304745945.2821.601.camel@edumazet-laptop> (raw)
Message-ID: <20110507052545.mQFqLeYhu2UOLhz8XmBsYNbWqazU4H6snMJTLfuzfME@z> (raw)
In-Reply-To: <1304743740-3405-1-git-send-email-xiaosuo@gmail.com>
Le samedi 07 mai 2011 à 12:49 +0800, Changli Gao a écrit :
> If FD_CLOFORK is 1, when a fork occurs, the corresponding file descriptor
> will be closed for the child process. IOW, the file descriptor isn't
> inheritable.
>
> FD_CLOFORK is used as IBM does.
Is it part of a standard, and what could be the use for such thing ?
Why had we wait 2011 to add it in linux ?
>
> O_CLOFORK is also added to avoid the additional fcntl(2) after open(2).
>
> Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Your implementation has some peformance implication.
close_on_exec and close_on_fork bit for a given fd would be on separate
cache lines. So you add a cost on threaded programs for open()/close()
[ Yes, we apparently clear close_on_exec bit in close()... we could let
it untouched and make flush_old_files() aware of that ]
next prev parent reply other threads:[~2011-05-07 5:25 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-07 4:49 [PATCH] fs: add FD_CLOFORK and O_CLOFORK Changli Gao
2011-05-07 5:25 ` Eric Dumazet [this message]
2011-05-07 5:25 ` Eric Dumazet
2011-05-07 10:09 ` Changli Gao
2011-05-07 6:06 ` Eric Dumazet
2011-05-07 6:06 ` Eric Dumazet
2011-05-07 6:22 ` Changli Gao
2011-05-07 6:29 ` Eric Dumazet
2011-05-07 10:10 ` Changli Gao
2011-05-07 11:41 ` Geert Uytterhoeven
2011-05-07 12:32 ` Eric Dumazet
2011-05-07 12:32 ` Eric Dumazet
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