From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932159AbWB1D0m (ORCPT ); Mon, 27 Feb 2006 22:26:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932162AbWB1D0m (ORCPT ); Mon, 27 Feb 2006 22:26:42 -0500 Received: from smtp.osdl.org ([65.172.181.4]:44978 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S932159AbWB1D0m (ORCPT ); Mon, 27 Feb 2006 22:26:42 -0500 Date: Mon, 27 Feb 2006 19:25:32 -0800 From: Andrew Morton To: "Rafael J. Wysocki" Cc: pavel@suse.cz, linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH -mm 2/2] mm: make shrink_all_memory try harder Message-Id: <20060227192532.0a71e19b.akpm@osdl.org> In-Reply-To: <200602271930.03171.rjw@sisk.pl> References: <200602271926.20294.rjw@sisk.pl> <200602271930.03171.rjw@sisk.pl> X-Mailer: Sylpheed version 1.0.4 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org "Rafael J. Wysocki" wrote: > > Make shrink_all_memory() repeat the attempts to free more memory if there > seems to be no pages to free. > This description doesn't describe what the problem is, not how the patch fixes it. So I'm kinda left guessing. > =================================================================== > --- linux-2.6.16-rc4-mm2.orig/mm/vmscan.c > +++ linux-2.6.16-rc4-mm2/mm/vmscan.c > @@ -33,6 +33,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -1793,17 +1794,24 @@ unsigned long shrink_all_memory(unsigned > struct reclaim_state reclaim_state = { > .reclaimed_slab = 0, > }; > + int retry = 2; > > current->reclaim_state = &reclaim_state; > - for_each_pgdat(pgdat) { > - unsigned long freed; > + do { > + for_each_pgdat(pgdat) { > + unsigned long freed; > > - freed = balance_pgdat(pgdat, nr_to_free, 0); > - ret += freed; > - nr_to_free -= freed; > - if (nr_to_free <= 0) > + freed = balance_pgdat(pgdat, nr_to_free, 0); > + ret += freed; > + nr_to_free -= freed; > + if (nr_to_free <= 0) > + break; > + } > + if (ret > 0) > break; > - } > + if (retry) > + msleep_interruptible(100); TASK_INTERRUPTIBLE sleeps won't do anything if someone has sent this process a signal. They should be used with caution. Something like the below, I guess. But it's hard to fix something when you don't know what you're fixing. swsusp should call drop_pagecache() and then drop_slab() before trying to use shrink_all_memory(), btw. diff -puN mm/vmscan.c~mm-make-shrink_all_memory-try-harder mm/vmscan.c --- devel/mm/vmscan.c~mm-make-shrink_all_memory-try-harder 2006-02-27 19:17:29.000000000 -0800 +++ devel-akpm/mm/vmscan.c 2006-02-27 19:21:08.000000000 -0800 @@ -33,6 +33,7 @@ #include #include #include +#include #include #include @@ -1783,11 +1784,13 @@ unsigned long shrink_all_memory(unsigned pg_data_t *pgdat; unsigned long nr_to_free = nr_pages; unsigned long ret = 0; + unsigned retry = 2; struct reclaim_state reclaim_state = { .reclaimed_slab = 0, }; current->reclaim_state = &reclaim_state; +repeat: for_each_pgdat(pgdat) { unsigned long freed; @@ -1797,6 +1800,10 @@ unsigned long shrink_all_memory(unsigned if ((long)nr_to_free <= 0) break; } + if (retry-- && ret < nr_pages) { + blk_congestion_wait(WRITE, HZ/5); + goto repeat; + } current->reclaim_state = NULL; return ret; } _ But then, the above could be implemented by the caller, so I don't know what's going on..