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From: Neil Brown <neilb@suse.de>
To: David Rientjes <rientjes@google.com>
Cc: Suresh Jayaraman <sjayaraman@suse.de>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	netdev@vger.kernel.org, Miklos Szeredi <mszeredi@suse.cz>,
	Wouter Verhelst <w@uter.be>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	trond.myklebust@fys.uio.no
Subject: Re: [PATCH 01/31] mm: serialize access to min_free_kbytes
Date: Fri, 2 Oct 2009 15:20:34 +1000	[thread overview]
Message-ID: <19141.36258.926599.862333@notabene.brown> (raw)
In-Reply-To: message from David Rientjes on Thursday October 1

On Thursday October 1, rientjes@google.com wrote:
> On Thu, 1 Oct 2009, Suresh Jayaraman wrote:
> 
> > From: Peter Zijlstra <a.p.zijlstra@chello.nl> 
> > 
> > There is a small race between the procfs caller and the memory hotplug caller
> > of setup_per_zone_wmarks(). Not a big deal, but the next patch will add yet
> > another caller. Time to close the gap.
> > 
> 
> By "next patch," you mean "mm: emegency pool" (patch 08/31)?

:-)  It is always safer to say "a subsequent patch", isn't it....

> 
> If so, can't you eliminate var_free_mutex entirely from that patch and 
> take min_free_lock in adjust_memalloc_reserve() instead?

adjust_memalloc_reserve does a test alloc/free cycle under a lock.
That cannot be done under a spin-lock, it must be a mutex.
So I don't think you can eliminate var_free_mutex.

Thanks,
NeilBrown

> 
>  [ __adjust_memalloc_reserve() would call __setup_per_zone_wmarks()
>    under lock instead, now. ]

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      reply	other threads:[~2009-10-02  5:20 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-10-01 14:04 [PATCH 01/31] mm: serialize access to min_free_kbytes Suresh Jayaraman
2009-10-01 20:35 ` David Rientjes
2009-10-02  5:20   ` Neil Brown [this message]

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