From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id D59326B01B8 for ; Thu, 14 May 2009 09:18:49 -0400 (EDT) Message-ID: <4A0C1A41.7040202@redhat.com> Date: Thu, 14 May 2009 09:18:57 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH] mmtom: Prevent shrinking of active anon lru list in case of no swap space V2 References: <20090514201150.8536f86e.minchan.kim@barrios-desktop> <4A0C1571.2020106@redhat.com> <28c262360905140609y580b6835m759dee08f08a26ab@mail.gmail.com> In-Reply-To: <28c262360905140609y580b6835m759dee08f08a26ab@mail.gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Minchan Kim Cc: Andrew Morton , LKML , linux-mm , KOSAKI Motohiro , Johannes Weiner List-ID: Minchan Kim wrote: > HI, Rik > > Thanks for careful review. :) > > On Thu, May 14, 2009 at 9:58 PM, Rik van Riel wrote: >> Minchan Kim wrote: >> >>> Now shrink_active_list is called several places. >>> But if we don't have a swap space, we can't reclaim anon pages. >> If swap space has run out, get_scan_ratio() will return >> 0 for the anon scan ratio, meaning we do not scan the >> anon lists. > > I think get_scan_ration can't prevent scanning of anon pages in no > swap system(like embedded system). > That's because in shrink_zone, you add following as > > /* > * Even if we did not try to evict anon pages at all, we want to > * rebalance the anon lru active/inactive ratio. > */ > if (inactive_anon_is_low(zone, sc)) > shrink_active_list(SWAP_CLUSTER_MAX, zone, sc, priority, 0); That's a fair point. How about we change this to: if (inactive_anon_is_low(zone, sc) && nr_swap_pages >= 0) That way GCC will statically optimize away this branch on systems with CONFIG_SWAP=n. Does that look reasonable? -- All rights reversed. -- 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