Messages in this thread | | | Date | Wed, 30 Dec 2009 22:13:42 +0900 (JST) | From | KOSAKI Motohiro <> | Subject | Re: [PATCH 3/4] vmstat: add anon_scan_ratio field to zoneinfo |
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> * KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> [2009-12-28 16:48:51]: > > > Vmscan folks was asked "why does my system makes so much swap-out?" > > in lkml at several times. > > At that time, I made the debug patch to show recent_anon_{scanned/rorated} > > parameter at least three times. > > > > Thus, its parameter should be showed on /proc/zoneinfo. It help > > vmscan folks debugging. > > > > Hmmm.. I think this should come under DEBUG_VM, a lot of tools use > /proc/zoneinfo, the additional overhead may be high.. no? Also, > I would recommend adding the additional details to the end, so > as to not break existing tools (specifically dump line # based > tools).
Thanks, I have three answer. 1) I really hope to don't enclose DEBUG_VM. otherwise my harm doesn't solve. 2) but your performance worry is fair enough. I plan to remove to grab zone->lru_lock in reading /proc/zoneinfo. 3) append new line doesn't break existing tools. because zoneinfo show vmstat and we often append new vmstat in past years. but I haven't seen zoneinfo breakage bug report. because zoneinfo file show multiple zone information, then nobody access it by line number.
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