From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 7 Jun 2001 14:43:58 -0300 (BRT) From: Marcelo Tosatti Subject: Please test: workaround to help swapoff behaviour In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Mike Galbraith Cc: "Eric W. Biederman" , Derek Glidden , lkml , linux-mm@kvack.org List-ID: On Thu, 7 Jun 2001, Marcelo Tosatti wrote: > > On Thu, 7 Jun 2001, Mike Galbraith wrote: > > > On 6 Jun 2001, Eric W. Biederman wrote: > > > > > Mike Galbraith writes: > > > > > > > > If you could confirm this by calling swapoff sometime other than at > > > > > reboot time. That might help. Say by running top on the console. > > > > > > > > The thing goes comatose here too. SCHED_RR vmstat doesn't run, console > > > > switch is nogo... > > > > > > > > After running his memory hog, swapoff took 18 seconds. I hacked a > > > > bleeder valve for dead swap pages, and it dropped to 4 seconds.. still > > > > utterly comatose for those 4 seconds though. > > > > > > At the top of the while(1) loop in try_to_unuse what happens if you put in. > > > if (need_resched) schedule(); > > > It should be outside all of the locks. It might just be a matter of everything > > > serializing on the SMP locks, and the kernel refusing to preempt itself. > > > > That did it. > > What about including this workaround in the kernel ? Well, This is for the people who has been experiencing the lockups while running swapoff. Please test. (against 2.4.6-pre1) Thanks for the suggestion, Eric. --- linux.orig/mm/swapfile.c Wed Jun 6 18:16:45 2001 +++ linux/mm/swapfile.c Thu Jun 7 16:06:11 2001 @@ -345,6 +345,8 @@ /* * Find a swap page in use and read it in. */ + if (current->need_resched) + schedule(); swap_device_lock(si); for (i = 1; i < si->max ; i++) { if (si->swap_map[i] > 0 && si->swap_map[i] != SWAP_MAP_BAD) { -- 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/