From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: Re: [PATCH 03/17] writeback: introduce writeback_control.inodes_cleaned Date: Mon, 16 May 2011 19:14:29 +0800 Message-ID: <20110516111429.GB5902@localhost> References: <20110512135706.937596128@intel.com> <20110512140031.025181367@intel.com> <20110512224420.GJ19446@dastard> <20110513033605.GC8016@localhost> <20110515235021.GP19446@dastard> <20110516104015.GA18520@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Dave Chinner , Andrew Morton , Jan Kara , Mel Gorman , "linux-fsdevel@vger.kernel.org" , LKML To: Christoph Hellwig Return-path: Content-Disposition: inline In-Reply-To: <20110516104015.GA18520@infradead.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Mon, May 16, 2011 at 06:40:16PM +0800, Christoph Hellwig wrote: > On Mon, May 16, 2011 at 09:50:21AM +1000, Dave Chinner wrote: > > > - nr_to_write has always been "# of pages written" and writeback_sb_inodes() > > > is actually making use of it to do page accounting in work->nr_pages. > > > > Do we really care whether it's inodes or pages that are written? As > > far as i can tell it doesn't, because writing inodes generally > > requires more IO and so needs to be limited anyway. > > We do care, but the current infrastructure already is bad enough to > not make it work. E.g. when calling from balance_dirty_pages we > couldn't care less if the inode is written back, we just want pages > on stable storage, similar for wakeups from the VM code. Sooner or > later there's no way around splitting page and inode writeback > completely. Agreed. > > So put the accounting in the post-write code in > > writeback_single_inode() where we already check if the inode is > > still dirty or not. Splitting per-inode post-write processing > > between writeback_single_inode and the higher level code is cludgy - > > I'd much prefer it done in only one place. > > I'd tend to agree. Especially as cleaner separation was the main > goal for getting rid of the writeback_control overload in the beginning. I wonder if this is what you want, which puts page and inode accounting together: writeback_single_inode(inode, wb, &wbc); work->nr_pages -= write_chunk - wbc.nr_to_write; wrote += write_chunk - wbc.nr_to_write; + if (!(inode->i_state & I_DIRTY)) + wrote++; + if (wbc.pages_skipped) { /* * writeback is not making progress due to locked * buffers. Skip this inode for now. */ redirty_tail(inode, wb); } Thanks, Fengguang