From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 30 Jun 2003 19:14:56 -0700 From: Andrew Morton Subject: Re: 2.5.73-mm2 Message-Id: <20030630191456.1aef22e0.akpm@digeo.com> In-Reply-To: <20030701003958.GB20413@holomorphy.com> References: <20030627202130.066c183b.akpm@digeo.com> <20030701003958.GB20413@holomorphy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: William Lee Irwin III Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: William Lee Irwin III wrote: > > @@ -217,9 +217,9 @@ void out_of_memory(void) > unsigned long now, since; > > /* > - * Enough swap space left? Not OOM. > + * Enough swap space and ZONE_NORMAL left? Not OOM. > */ > - if (nr_swap_pages > 0) > + if (nr_swap_pages > 0 && nr_free_buffer_pages() + nr_used_low_pages() > 0) > return; a) if someone is trying to allocate some ZONE_DMA pages and there are still swappable or free ZONE_NORMAL pages, nobody gets killed. b) If there are free ZONE_NORMAL pages then why on earth did we call out_of_memory()? Does nr_free_buffer_pages() ever return non-zero in here? It will do so for a ZONE_DMA allocation, but you're not doing them... Generally, I'm thinking that this test should just be removed. It is the responsibility of try_to_free_pages() to work out whether the allocation can succeed. If try_to_free_pages() calls out_of_memory() when there are still swappable, reclaimable or free pages in the relevant zones then try_to_free_pages() goofed, and needs mending. out_of_memory() shouldn't be cleaning up after try_to_free_pages()'s mistakes. I have a bad feeling that it _will_ goof. A long time ago I looked at the amount of scanning we're doing in there and decided that it was way overkill and reduced it by a lot. I may have gone overboard. So how's about I and thy take that test out, see how things get along? -- 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/ . Don't email: aart@kvack.org