linux-kernel - Re: [GIT PULL] killable rwsems for v4.7

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Message-ID: <20160517070837.GB14453@dhcp22.suse.cz>
Date:	Tue, 17 May 2016 09:08:38 +0200
From:	Michal Hocko <mhocko@...nel.org>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Ingo Molnar <mingo@...nel.org>, Al Viro <viro@...iv.linux.org.uk>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [GIT PULL] killable rwsems for v4.7

On Mon 16-05-16 13:32:28, Linus Torvalds wrote:
> On Mon, May 16, 2016 at 7:55 AM, Ingo Molnar <mingo@...nel.org> wrote:
> >
> > This tree, by Michal Hocko, implements down_write_killable(). The main usecase
> > will be to update mm_sem usage sites to use this new API,
> 
> Hmm. Is somebody (Michal?) looking at down_read_killable() too?

I wasn't because I didn't need it for my oom_reaper use case.

> The VFS layer will want it with the pending parallel lookup code - the
> inode semaphore is being converted to a rwsem, and there's a couple of
> "killable" users.. The first step actually just wants to the exclusive
> case (ie the write case that this adds), but I think the readdir code
> could really use a reading version too..

This is more a question for Al but I do not think adding killable read
lock is a big deal. I can certainly help with it.
-- 
Michal Hocko
SUSE Labs