On Fri, Apr 06, 2012 at 04:52:09PM -0700, Ying Han wrote: > On Wed, Mar 28, 2012 at 9:06 AM, Mel Gorman <mgorman@xxxxxxx> wrote: > > Lumpy reclaim had a purpose but in the mind of some, it was to kick > > the system so hard it trashed. For others the purpose was to complicate > > vmscan.c. Over time it was giving softer shoes and a nicer attitude but > > memory compaction needs to step up and replace it so this patch sends > > lumpy reclaim to the farm. > > > > Here are the important notes related to the patch. > > > > 1. The tracepoint format changes for isolating LRU pages. > > > > 2. This patch stops reclaim/compaction entering sync reclaim as this > > was only intended for lumpy reclaim and an oversight. Page migration > > has its own logic for stalling on writeback pages if necessary and > > memory compaction is already using it. This is a behaviour change. > > > > 3. RECLAIM_MODE_SYNC no longer exists. pageout() does not stall > > on PageWriteback with CONFIG_COMPACTION has been this way for a while. > > I am calling it out in case this is a surpise to people. > > Mel, > > Can you point me the commit making that change? I am looking at > v3.4-rc1 where set_reclaim_mode() still set RECLAIM_MODE_SYNC for > COMPACTION_BUILD. > You're right. There is only one call site that passes sync==true for set_reclaim_mode() in vmscan.c and that is only if should_reclaim_stall() returns true. It had the comment "Only stall on lumpy reclaim" but the comment is not accurate and that mislead me. Thanks, I'll revisit the patch. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>