From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: Re: [PATCH 1/3 v2] mm: Stop background writeback if there is other work queued for the thread Date: Sun, 8 Aug 2010 00:04:00 +0800 Message-ID: <20100807160400.GA6027@localhost> References: <1281034399-13055-1-git-send-email-jack@suse.cz> <1281034399-13055-2-git-send-email-jack@suse.cz> <20100805164535.f28d8807.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kara , "linux-fsdevel@vger.kernel.org" , "hch@infradead.org" , "jaxboe@fusionio.com" To: Andrew Morton Return-path: Received: from mga11.intel.com ([192.55.52.93]:43936 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753593Ab0HGQVS (ORCPT ); Sat, 7 Aug 2010 12:21:18 -0400 Content-Disposition: inline In-Reply-To: <20100805164535.f28d8807.akpm@linux-foundation.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Fri, Aug 06, 2010 at 07:45:35AM +0800, Andrew Morton wrote: > On Thu, 5 Aug 2010 20:53:17 +0200 > Jan Kara wrote: > > > Background writeback and kupdate-style writeback > > What the heck's the difference between "Background writeback" and > "kupdate-style" writeback? afacit "background" means "not due to > kupdate, but due to a vmscan poke or something like that". But the > terms aren't defined anywhere and the wb_writeback_work fields are > uncommented and the functions are undocumented and no wonder we keep > making such a mess of this code. I happen to describe these terms in another email :) ...there are always four main writeback goals/semantics: - periodic stop when all 30s-old inodes are written - background stop when background threshold is reached - nr_pages stop when nr_pages written (or when all clean) - sync stop when all older-than-sync-time inodes/pages are written Thanks, Fengguang