From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frans Pop Subject: Re: [PATCH 3/3] vmscan: Force kswapd to take notice faster when high-order watermarks are being hit Date: Tue, 3 Nov 2009 23:01:50 +0100 Message-ID: <200911032301.59662.elendil@planet.nl> References: <1256650833-15516-1-git-send-email-mel@csn.ul.ie> <200911021832.59035.elendil@planet.nl> <20091102173837.GB22046@csn.ul.ie> Mime-Version: 1.0 Content-Type: Multipart/Mixed; boundary="Boundary-00=_XhK8KFWl4pYC5hC" Return-path: In-Reply-To: <20091102173837.GB22046@csn.ul.ie> Sender: owner-linux-mm@kvack.org List-Id: To: Mel Gorman Cc: Andrew Morton , stable@kernel.org, linux-kernel@vger.kernel.org, "linux-mm@kvack.org" , Jiri Kosina , Sven Geggus , Karol Lewandowski , Tobias Oetiker , KOSAKI Motohiro , Pekka Enberg , Rik van Riel , Christoph Lameter , Stephan von Krawczynski , Kernel Testers List --Boundary-00=_XhK8KFWl4pYC5hC Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline On Monday 02 November 2009, Mel Gorman wrote: > On Mon, Nov 02, 2009 at 06:32:54PM +0100, Frans Pop wrote: > > On Monday 02 November 2009, Mel Gorman wrote: > > > vmscan: Help debug kswapd issues by counting number of rewakeups and > > > premature sleeps > > > > > > There is a growing amount of anedotal evidence that high-order > > > atomic allocation failures have been increasing since 2.6.31-rc1. > > > The two strongest possibilities are a marked increase in the number > > > of GFP_ATOMIC allocations and alterations in timing. Debugging > > > printk patches have shown for example that kswapd is sleeping for > > > shorter intervals and going to sleep when watermarks are still not > > > being met. > > > > > > This patch adds two kswapd counters to help identify if timing is an > > > issue. The first counter kswapd_highorder_rewakeup counts the number > > > of times that kswapd stops reclaiming at one order and restarts at a > > > higher order. The second counter kswapd_slept_prematurely counts the > > > number of times kswapd went to sleep when the high watermark was not > > > met. > > > > What testing would you like done with this patch? > > Same reproduction as before except post what the contents of > /proc/vmstat were after the problem was triggered. With a representative test I get 0 for kswapd_slept_prematurely. Tested with .32-rc6 + patches 1-3 + this patch. --Boundary-00=_XhK8KFWl4pYC5hC Content-Type: text/plain; charset="iso-8859-15"; name="vmstat" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="vmstat" nr_free_pages 4841 nr_inactive_anon 103124 nr_active_anon 305446 nr_inactive_file 20214 nr_active_file 9217 nr_unevictable 400 nr_mlock 400 nr_anon_pages 364727 nr_mapped 2907 nr_file_pages 74823 nr_dirty 1 nr_writeback 0 nr_slab_reclaimable 2749 nr_slab_unreclaimable 4024 nr_page_table_pages 4286 nr_kernel_stack 177 nr_unstable 0 nr_bounce 0 nr_vmscan_write 226841 nr_writeback_temp 0 nr_isolated_anon 0 nr_isolated_file 0 nr_shmem 18 pgpgin 651718 pgpgout 918016 pswpin 10144 pswpout 226833 pgalloc_dma 2193 pgalloc_dma32 1965234 pgalloc_normal 0 pgalloc_movable 0 pgfree 1972499 pgactivate 124982 pgdeactivate 387354 pgfault 2237876 pgmajfault 7305 pgrefill_dma 1538 pgrefill_dma32 388961 pgrefill_normal 0 pgrefill_movable 0 pgsteal_dma 67 pgsteal_dma32 305556 pgsteal_normal 0 pgsteal_movable 0 pgscan_kswapd_dma 192 pgscan_kswapd_dma32 419147 pgscan_kswapd_normal 0 pgscan_kswapd_movable 0 pgscan_direct_dma 576 pgscan_direct_dma32 299638 pgscan_direct_normal 0 pgscan_direct_movable 0 pginodesteal 2504 slabs_scanned 40960 kswapd_steal 250714 kswapd_inodesteal 6259 kswapd_highorder_rewakeup 22 kswapd_slept_prematurely 0 pageoutrun 3502 allocstall 975 pgrotated 226573 unevictable_pgs_culled 4251 unevictable_pgs_scanned 0 unevictable_pgs_rescued 33344 unevictable_pgs_mlocked 43192 unevictable_pgs_munlocked 42780 unevictable_pgs_cleared 2 unevictable_pgs_stranded 0 unevictable_pgs_mlockfreed 0 --Boundary-00=_XhK8KFWl4pYC5hC-- -- 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