From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [patch] nfs: use GFP_NOFS preloads for radix-tree insertion From: Peter Zijlstra In-Reply-To: <20071114042011.GE557@wotan.suse.de> References: <20071108013723.GF3227@wotan.suse.de> <20071107190254.4e65812a.akpm@linux-foundation.org> <20071108031645.GI3227@wotan.suse.de> <20071107201242.390aec38.akpm@linux-foundation.org> <20071108045404.GJ3227@wotan.suse.de> <20071107210204.62070047.akpm@linux-foundation.org> <20071108054445.GA20162@wotan.suse.de> <20071107220200.85e9cb59.akpm@linux-foundation.org> <20071108065633.GB28216@wotan.suse.de> <1194951345.6983.24.camel@twins> <20071114042011.GE557@wotan.suse.de> Content-Type: text/plain Date: Wed, 14 Nov 2007 10:06:27 +0100 Message-Id: <1195031187.6924.1.camel@twins> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: Andrew Morton , linux-mm@kvack.org, davem@davemloft.net, Trond Myklebust List-ID: On Wed, 2007-11-14 at 05:20 +0100, Nick Piggin wrote: > On Tue, Nov 13, 2007 at 11:55:45AM +0100, Peter Zijlstra wrote: > > > > On Thu, 2007-11-08 at 07:56 +0100, Nick Piggin wrote: > > > Here is the NFS version. I guess Trond should ack it before you pick it > > > up. > > > > > > -- > > > > > > NFS should use GFP_NOFS mode radix tree preloads rather than GFP_ATOMIC > > > allocations at radix-tree insertion-time. This is important to reduce the > > > atomic memory requirement. > > > > In another mail you said: > > > > > Anyway we can also simplify the code because the insertion can't fail with a > > > preload. > > > > Can we please avoid adding strict dependencies on that as the preload > > API is unsupportable in -rt. > > You can surely support it. You just have to do per-thread preloads if you > want preemption left on. Well, true, but that would mean adding stuff to task_struct, not the end of the world I guess. But as it is leaving the error handling on each individual radix_tree_insert() allows us to just use GFP_KERNEL for everything. The other, nicer option, is to do preload on the radix_tree_context object instead. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org