From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx167.postini.com [74.125.245.167]) by kanga.kvack.org (Postfix) with SMTP id 25C996B004D for ; Fri, 20 Apr 2012 20:21:40 -0400 (EDT) From: Satoru Moriya Date: Fri, 20 Apr 2012 20:21:28 -0400 Subject: RE: [RFC][PATCH] avoid swapping out with swappiness==0 Message-ID: <65795E11DBF1E645A09CEC7EAEE94B9C014575D8CF@USINDEVS02.corp.hds.com> References: <65795E11DBF1E645A09CEC7EAEE94B9CB9455FE2@USINDEVS02.corp.hds.com> <20120305215602.GA1693@redhat.com> <4F5798B1.5070005@jp.fujitsu.com> <65795E11DBF1E645A09CEC7EAEE94B9CB951A45F@USINDEVS02.corp.hds.com> <65795E11DBF1E645A09CEC7EAEE94B9C01454D13A6@USINDEVS02.corp.hds.com> <4F7ADE1A.2050004@redhat.com> <4F7C870B.6020807@gmail.com> In-Reply-To: <4F7C870B.6020807@gmail.com> Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro , Jerome Marchand Cc: KOSAKI Motohiro , "jweiner@redhat.com" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "riel@redhat.com" , "lwoodman@redhat.com" , "shaohua.li@intel.com" , "dle-develop@lists.sourceforge.net" , Seiji Aguchi Hi, Sorry for my late reply. On 04/04/2012 01:38 PM, KOSAKI Motohiro wrote: > (4/3/12 4:25 AM), Jerome Marchand wrote: >> On 04/02/2012 07:10 PM, KOSAKI Motohiro wrote: >>> 2012/3/30 Satoru Moriya: >>>> So the kernel reclaims pages like following. >>>> >>>> nr_free + nr_filebacked>=3D watermark_high: reclaim only filebacked pa= ges >>>> nr_free + nr_filebacked< watermark_high: reclaim only anonymous page= s >>> >>> How? >> >> get_scan_count() checks that case explicitly: >> >> if (global_reclaim(sc)) { >> free =3D zone_page_state(mz->zone, NR_FREE_PAGES); >> /* If we have very few page cache pages, >> force-scan anon pages. */ >> if (unlikely(file + free<=3D high_wmark_pages(mz->zone))) { >> fraction[0] =3D 1; >> fraction[1] =3D 0; >> denominator =3D 1; >> goto out; >> } >> } >=20 > Eek. This is silly. Nowaday many people enabled THP and it increase zone = watermark. > so, high watermask is not good threshold anymore. Ah yes, it is not so small now. On 4GB server, without THP min_free_kbytes is 8113 but with THP it is 67584. How about using low watermark or min watermark? Are they still big? ...or should we use other value?=20 Regards, Satoru -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org