From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 22 Jun 2000 16:47:50 -0300 (BRST) From: Rik van Riel Subject: Re: [PATCH] Re: latancy test of -ac22-riel 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: John Fremlin Cc: Roger Larsson , linux-mm@kvack.org List-ID: On 22 Jun 2000, John Fremlin wrote: > Roger Larsson writes: > > [...] > > > I retried running with normal prio - then I get stalls > > of > 350ms... > > I think some stalls are most probably due to try_to_free_pages below > > page_alloc.c::__alloc_pages > /* > * Uhhuh. All the zones have been critical, which means that > * we'd better do some synchronous swap-out. kswapd has not > * been able to cope.. > */ > if (!(current->flags & PF_MEMALLOC)) { > if (!try_to_free_pages(gfp_mask)) { > if (!(gfp_mask & __GFP_HIGH)) > goto fail; > } > goto fail; > } > > That is, it happens in times of high memory stress and when I > comment it out the pauses go away but I'm not sure that this is > a good long-term solution ;-) though IMHO the behaviour without > it (VM killing process) is better than the behaviour with it > (paging until power is cycled). You're confusing things here. If kswapd was too slow in freeing up memory, but there is still more memory available, then we should NOT kill a process but just stall the process until more memory is available. OTOH, when we are truly Out Of Memory, then (and only then) should we kill a process. Killing a process before we are out of memory is just not acceptable and should never be done. regards, Rik -- The Internet is not a network of computers. It is a network of people. That is its real strength. Wanna talk about the kernel? irc.openprojects.net / #kernelnewbies http://www.conectiva.com/ http://www.surriel.com/ -- 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.eu.org/Linux-MM/