From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757211AbZBIToT (ORCPT ); Mon, 9 Feb 2009 14:44:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754198AbZBIToE (ORCPT ); Mon, 9 Feb 2009 14:44:04 -0500 Received: from cmpxchg.org ([85.214.51.133]:41684 "EHLO cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754195AbZBIToB (ORCPT ); Mon, 9 Feb 2009 14:44:01 -0500 Date: Mon, 9 Feb 2009 20:43:09 +0100 From: Johannes Weiner To: MinChan Kim Cc: KOSAKI Motohiro , Andrew Morton , "Rafael J. Wysocki" , Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [patch] vmscan: rename sc.may_swap to may_unmap Message-ID: <20090209194309.GA8491@cmpxchg.org> References: <20090206122129.79CC.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20090206044907.GA18467@cmpxchg.org> <20090206135302.628E.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20090206122417.GB1580@cmpxchg.org> <28c262360902060535g22facdd0tf082ca0abaec3f80@mail.gmail.com> <28c262360902060915u18b2fb54t5f2c1f44d03306e3@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <28c262360902060915u18b2fb54t5f2c1f44d03306e3@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org sc.may_swap does not only influence reclaiming of anon pages but pages mapped into pagetables in general, which also includes mapped file pages. >>From shrink_page_list(): if (!sc->may_swap && page_mapped(page)) goto keep_locked; For anon pages, this makes sense as they are always mapped and reclaiming them always requires swapping. But mapped file pages are skipped here as well and it has nothing to do with swapping. The real effect of the knob is whether mapped pages are unmapped and reclaimed or not. Rename it to `may_unmap' to have its name match its actual meaning more precisely. Signed-off-by: Johannes Weiner --- mm/vmscan.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) On Sat, Feb 07, 2009 at 02:15:21AM +0900, MinChan Kim wrote: > Sorry for misunderstood your point. > It would be better to remain more detaily for git log ? > > 'may_swap' applies not only to anon pages but to mapped file pages as > well. 'may_swap' term is sometime used for 'swap', sometime used for > 'sync|discard'. > In case of anon pages, 'may_swap' determines whether pages were swapout or not. > but In case of mapped file pages, it determines whether pages are > synced or discarded. so, 'may_swap' is rather awkward. Rename it to > 'may_unmap' which is the actual meaning. > > If you find wrong word and sentence, Please, fix it. :) Is the above description okay for you? Andrew, this is on top of the two earlier clean ups in vmscan.c: + swsusp-clean-up-shrink_all_zones.patch + swsusp-dont-fiddle-with-swappiness.patch --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -60,8 +60,8 @@ struct scan_control { int may_writepage; - /* Can pages be swapped as part of reclaim? */ - int may_swap; + /* Can mapped pages be reclaimed? */ + int may_unmap; /* This context's SWAP_CLUSTER_MAX. If freeing memory for * suspend, we effectively ignore SWAP_CLUSTER_MAX. @@ -606,7 +606,7 @@ static unsigned long shrink_page_list(st if (unlikely(!page_evictable(page, NULL))) goto cull_mlocked; - if (!sc->may_swap && page_mapped(page)) + if (!sc->may_unmap && page_mapped(page)) goto keep_locked; /* Double the slab pressure for mapped and swapcache pages */ @@ -1694,7 +1694,7 @@ unsigned long try_to_free_pages(struct z .gfp_mask = gfp_mask, .may_writepage = !laptop_mode, .swap_cluster_max = SWAP_CLUSTER_MAX, - .may_swap = 1, + .may_unmap = 1, .swappiness = vm_swappiness, .order = order, .mem_cgroup = NULL, @@ -1713,7 +1713,7 @@ unsigned long try_to_free_mem_cgroup_pag { struct scan_control sc = { .may_writepage = !laptop_mode, - .may_swap = 1, + .may_unmap = 1, .swap_cluster_max = SWAP_CLUSTER_MAX, .swappiness = swappiness, .order = 0, @@ -1723,7 +1723,7 @@ unsigned long try_to_free_mem_cgroup_pag struct zonelist *zonelist; if (noswap) - sc.may_swap = 0; + sc.may_unmap = 0; sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) | (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK); @@ -1762,7 +1762,7 @@ static unsigned long balance_pgdat(pg_da struct reclaim_state *reclaim_state = current->reclaim_state; struct scan_control sc = { .gfp_mask = GFP_KERNEL, - .may_swap = 1, + .may_unmap = 1, .swap_cluster_max = SWAP_CLUSTER_MAX, .swappiness = vm_swappiness, .order = order, @@ -2108,7 +2108,7 @@ unsigned long shrink_all_memory(unsigned struct reclaim_state reclaim_state; struct scan_control sc = { .gfp_mask = GFP_KERNEL, - .may_swap = 0, + .may_unmap = 0, .swap_cluster_max = nr_pages, .may_writepage = 1, .isolate_pages = isolate_pages_global, @@ -2145,7 +2145,7 @@ unsigned long shrink_all_memory(unsigned /* Force reclaiming mapped pages in the passes #3 and #4 */ if (pass > 2) - sc.may_swap = 1; + sc.may_unmap = 1; for (prio = DEF_PRIORITY; prio >= 0; prio--) { unsigned long nr_to_scan = nr_pages - ret; @@ -2288,7 +2288,7 @@ static int __zone_reclaim(struct zone *z int priority; struct scan_control sc = { .may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE), - .may_swap = !!(zone_reclaim_mode & RECLAIM_SWAP), + .may_unmap = !!(zone_reclaim_mode & RECLAIM_SWAP), .swap_cluster_max = max_t(unsigned long, nr_pages, SWAP_CLUSTER_MAX), .gfp_mask = gfp_mask,