From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with ESMTP id 414DC6B004A for ; Wed, 17 Nov 2010 19:50:16 -0500 (EST) Date: Wed, 17 Nov 2010 16:49:24 -0800 From: Andrew Morton Subject: Re: [PATCH v4 05/11] writeback: create dirty_info structure Message-Id: <20101117164924.25e6cc11.akpm@linux-foundation.org> In-Reply-To: <1288336154-23256-6-git-send-email-gthelen@google.com> References: <1288336154-23256-1-git-send-email-gthelen@google.com> <1288336154-23256-6-git-send-email-gthelen@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Greg Thelen Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, containers@lists.osdl.org, Andrea Righi , Balbir Singh , KAMEZAWA Hiroyuki , Daisuke Nishimura , Minchan Kim , Ciju Rajan K , David Rientjes , Wu Fengguang List-ID: On Fri, 29 Oct 2010 00:09:08 -0700 Greg Thelen wrote: > Bundle dirty limits and dirty memory usage metrics into a dirty_info > structure to simplify interfaces of routines that need all. Problems... These patches interact pretty badly with Fengguang's "IO-less dirty throttling v2" patches. I fixed up writeback-create-dirty_info-structure.patch pretty mechanically but when it got to memcg-check-memcg-dirty-limits-in-page-writeback.patch things got sticky and I gave up. As your stuff was merged first, I'd normally send the bad news to Fengguang, but the memcg code is logically built upon the core writeback code so I do think these patches should be staged after the changes to core writeback. Also, while I was there it seemed that the chosen members of the dirty_info structure were a bit random. Perhaps we should be putting nr_dirty in there as well, perhaps other things. Please have a think about that. Also, in ratelimit_pages() we call global_dirty_info() to return four items, but that caller only actually uses two of them. Wasted effort? So I'm afraid I'm going to have to request that you redo and retest these patches: writeback-create-dirty_info-structure.patch memcg-add-dirty-page-accounting-infrastructure.patch memcg-add-kernel-calls-for-memcg-dirty-page-stats.patch memcg-add-dirty-limits-to-mem_cgroup.patch memcg-add-dirty-limits-to-mem_cgroup-use-native-word-to-represent-dirtyable-pages.patch memcg-add-dirty-limits-to-mem_cgroup-catch-negative-per-cpu-sums-in-dirty-info.patch memcg-add-dirty-limits-to-mem_cgroup-avoid-overflow-in-memcg_hierarchical_free_pages.patch memcg-add-dirty-limits-to-mem_cgroup-correct-memcg_hierarchical_free_pages-return-type.patch memcg-add-dirty-limits-to-mem_cgroup-avoid-free-overflow-in-memcg_hierarchical_free_pages.patch memcg-cpu-hotplug-lockdep-warning-fix.patch memcg-add-cgroupfs-interface-to-memcg-dirty-limits.patch memcg-break-out-event-counters-from-other-stats.patch memcg-check-memcg-dirty-limits-in-page-writeback.patch memcg-use-native-word-page-statistics-counters.patch memcg-use-native-word-page-statistics-counters-fix.patch # memcg-add-mem_cgroup-parameter-to-mem_cgroup_page_stat.patch memcg-pass-mem_cgroup-to-mem_cgroup_dirty_info.patch #memcg-make-throttle_vm_writeout-memcg-aware.patch: "troublesome": Kamezawa memcg-make-throttle_vm_writeout-memcg-aware.patch memcg-make-throttle_vm_writeout-memcg-aware-fix.patch memcg-simplify-mem_cgroup_page_stat.patch memcg-simplify-mem_cgroup_dirty_info.patch memcg-make-mem_cgroup_page_stat-return-value-unsigned.patch against the http://userweb.kernel.org/~akpm/mmotm/ which I just uploaded, sorry. I've uploaded my copy of all the above to http://userweb.kernel.org/~akpm/stuff/gthelen.tar.gz. I think only the two patches need fixing and retesting. Also, while wrangling the above patches, I stumbled across rejects such as: *************** *** 99,106 **** "state: %8lx\n", (unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)), (unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)), - K(bdi_thresh), K(dirty_thresh), - K(background_thresh), nr_dirty, nr_io, nr_more_io, !list_empty(&bdi->bdi_list), bdi->state); #undef K --- 98,106 ---- "state: %8lx\n", (unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)), (unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)), + K(bdi_thresh), K(dirty_info.dirty_thresh), + K(dirty_info.background_thresh), + nr_dirty, nr_io, nr_more_io, !list_empty(&bdi->bdi_list), bdi->state); Please, if you discover crud like this, just fix it up. One item per line: "state: %8lx\n", (unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)), (unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)), K(bdi_thresh), K(dirty_info.dirty_thresh), K(dirty_info.background_thresh), nr_dirty, nr_io, nr_more_io, !list_empty(&bdi->bdi_list), bdi->state); all very simple. And while you're there, fix up the tab-tab-space-space-space indenting - just use tabs. The other area where code maintenance is harder than it needs to be is in definitions of locals: long nr_reclaimable; long nr_dirty, bdi_dirty; /* = file_dirty + writeback + unstable_nfs */ long bdi_prev_dirty = 0; again, that's just dopey. Change it to long nr_reclaimable; long nr_dirty; long bdi_dirty; /* = file_dirty + writeback + unstable_nfs */ long bdi_prev_dirty = 0; All very simple. Thanks. -- 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/ . 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