From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id 479316B004D for ; Wed, 26 Aug 2009 14:26:41 -0400 (EDT) Received: by fxm18 with SMTP id 18so355340fxm.38 for ; Wed, 26 Aug 2009 11:26:48 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <8acda98c0908260507s7b813292i54b2d782cbfaadfe@mail.gmail.com> Date: Wed, 26 Aug 2009 22:26:48 +0400 Message-ID: <8acda98c0908261126s699480c8l4550f5b0798c9d7@mail.gmail.com> Subject: Re: [PATCH] mm/vmscan: change generic_file_write() comment to do_sync_write() From: Nikita Danilov Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org To: Vincent Li Cc: Christoph Hellwig , linux-mm@kvack.org, Badari Pulavarty , Andrew Morton List-ID: 2009/8/26 Vincent Li [...] > Thank you for the explaintion! > > =A0 =A0 =A0 =A0* If this process is currently in generic_file_write() aga= inst > =A0 =A0 =A0 =A0* this page's queue, we can perform writeback even if that > =A0 =A0 =A0 =A0* will block. > > So my interpretation for the comment is that if the current process is > already in __generic_file_aio_write against the page's queue, The page > claim path code can still perfom writeback even if the __generic_file_aio= _write > will block. Am I right? Yes. The idea is that=A0a heavy writer causing a lot of page allocations should wait for the queue to drain, thus throttling itself; while a thread that triggeres direct reclaim occasionally (i.e., not from the main write path) shouldn't be blocked on the transput incurred by somebody else. Nikita. > > > > Vincent Li > Biomedical Research Center > University of British Columbia -- 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