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Date: Tue, 7 Mar 2017 06:00:54 +0100
From: Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH] xfs: remove kmem_zalloc_greedy
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References: <20170306184109.GC5280@birch.djwong.org> <20170307000754.GA9959@lst.de> <20170307001327.GC5281@birch.djwong.org> <20170307005420.GO17542@dastard>
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To: Dave Chinner <david@fromorbit.com>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>, Christoph Hellwig <hch@lst.de>, Brian Foster <bfoster@redhat.com>, Michal Hocko <mhocko@kernel.org>, Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>, Xiong Zhou <xzhou@redhat.com>, linux-xfs@vger.kernel.org, linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>, linux-fsdevel@vger.kernel.org, Michal Hocko <mhocko@suse.com>

On Tue, Mar 07, 2017 at 11:54:20AM +1100, Dave Chinner wrote:
> > Or maybe I've misunderstood, and you're asking if we should try
> > kmem_zalloc(4 pages), then kmem_zalloc(1 page), and only then switch to
> > the __vmalloc calls?
> 
> Just call kmem_zalloc_large() for 4 pages without a fallback on
> failure - that's exactly how we handle allocations for things like
> the 64k xattr buffers....

Yeah, that sounds fine.  I didn't remember that we actually tried
kmalloc before vmalloc for kmem_zalloc_large.