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 BCAD66B01EE for ; Wed, 31 Mar 2010 06:34:20 -0400 (EDT) Received: from wpaz17.hot.corp.google.com (wpaz17.hot.corp.google.com [172.24.198.81]) by smtp-out.google.com with ESMTP id o2VAYEdW032563 for ; Wed, 31 Mar 2010 12:34:16 +0200 Received: from pwj8 (pwj8.prod.google.com [10.241.219.72]) by wpaz17.hot.corp.google.com with ESMTP id o2VAYB4Q016423 for ; Wed, 31 Mar 2010 03:34:12 -0700 Received: by pwj8 with SMTP id 8so10083501pwj.15 for ; Wed, 31 Mar 2010 03:34:11 -0700 (PDT) Date: Wed, 31 Mar 2010 03:34:08 -0700 (PDT) From: David Rientjes Subject: Re: [PATCH V2 4/4] cpuset,mm: update task's mems_allowed lazily In-Reply-To: <4BB31BDA.8080203@cn.fujitsu.com> Message-ID: References: <4B94CD2D.8070401@cn.fujitsu.com> <4B95F802.9020308@cn.fujitsu.com> <20100311081548.GJ5812@laptop> <4B98C6DE.3060602@cn.fujitsu.com> <20100311110317.GL5812@laptop> <4BB31BDA.8080203@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Miao Xie Cc: Nick Piggin , Lee Schermerhorn , Paul Menage , Linux-Kernel , Linux-MM , Li Zefan , Andrew Morton List-ID: On Wed, 31 Mar 2010, Miao Xie wrote: > diff --git a/mm/mmzone.c b/mm/mmzone.c > index f5b7d17..43ac21b 100644 > --- a/mm/mmzone.c > +++ b/mm/mmzone.c > @@ -58,6 +58,7 @@ struct zoneref *next_zones_zonelist(struct zoneref *z, > nodemask_t *nodes, > struct zone **zone) > { > + nodemask_t tmp_nodes; > /* > * Find the next suitable zone to use for the allocation. > * Only filter based on nodemask if it's set > @@ -65,10 +66,16 @@ struct zoneref *next_zones_zonelist(struct zoneref *z, > if (likely(nodes == NULL)) > while (zonelist_zone_idx(z) > highest_zoneidx) > z++; > - else > - while (zonelist_zone_idx(z) > highest_zoneidx || > - (z->zone && !zref_in_nodemask(z, nodes))) > - z++; > + else { > + tmp_nodes = *nodes; > + if (nodes_empty(tmp_nodes)) > + while (zonelist_zone_idx(z) > highest_zoneidx) > + z++; > + else > + while (zonelist_zone_idx(z) > highest_zoneidx || > + (z->zone && !zref_in_nodemask(z, &tmp_nodes))) > + z++; > + } > > *zone = zonelist_zone(z); > return z; Unfortunately, you can't allocate a nodemask_t on the stack here because this is used in the iteration for get_page_from_freelist() which can occur very deep in the stack already and there's a probability of overflow. Dynamically allocating a nodemask_t simply wouldn't scale here, either, since it would allocate on every iteration of a zonelist. -- 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