From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f179.google.com (mail-wi0-f179.google.com [209.85.212.179]) by kanga.kvack.org (Postfix) with ESMTP id 5AF5D6B0035 for ; Tue, 6 May 2014 17:05:21 -0400 (EDT) Received: by mail-wi0-f179.google.com with SMTP id bs8so266585wib.6 for ; Tue, 06 May 2014 14:05:20 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTP id m3si6086533wje.91.2014.05.06.14.05.19 for ; Tue, 06 May 2014 14:05:20 -0700 (PDT) Message-ID: <53694E7D.6060706@redhat.com> Date: Tue, 06 May 2014 17:05:01 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 3/5] nfsd: Only set PF_LESS_THROTTLE when really needed. References: <20140423022441.4725.89693.stgit@notabene.brown> <20140423024058.4725.38098.stgit@notabene.brown> In-Reply-To: <20140423024058.4725.38098.stgit@notabene.brown> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: NeilBrown , Jan Kara , Jeff Layton , Trond Myklebust , Dave Chinner , "J. Bruce Fields" , Mel Gorman , Andrew Morton Cc: linux-mm@kvack.org, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org On 04/22/2014 10:40 PM, NeilBrown wrote: > PF_LESS_THROTTLE has a very specific use case: to avoid deadlocks > and live-locks while writing to the page cache in a loop-back > NFS mount situation. > > It therefore makes sense to *only* set PF_LESS_THROTTLE in this > situation. > We now know when a request came from the local-host so it could be a > loop-back mount. We already know when we are handling write requests, > and when we are doing anything else. > > So combine those two to allow nfsd to still be throttled (like any > other process) in every situation except when it is known to be > problematic. The FUSE code has something similar, but on the "client" side. See BDI_CAP_STRICTLIMIT in mm/writeback.c Would it make sense to use that flag on loopback-mounted NFS filesystems? -- All rights reversed -- 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