From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id ABBBF6B004F for ; Tue, 21 Apr 2009 04:49:27 -0400 (EDT) Date: Tue, 21 Apr 2009 09:50:08 +0100 From: Mel Gorman Subject: Re: [PATCH 18/25] Do not disable interrupts in free_page_mlock() Message-ID: <20090421085007.GG12713@csn.ul.ie> References: <1240266011-11140-1-git-send-email-mel@csn.ul.ie> <1240266011-11140-19-git-send-email-mel@csn.ul.ie> <1240300507.771.52.camel@penberg-laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <1240300507.771.52.camel@penberg-laptop> Sender: owner-linux-mm@kvack.org To: Pekka Enberg Cc: Linux Memory Management List , KOSAKI Motohiro , Christoph Lameter , Nick Piggin , Linux Kernel Mailing List , Lin Ming , Zhang Yanmin , Peter Zijlstra , Andrew Morton List-ID: On Tue, Apr 21, 2009 at 10:55:07AM +0300, Pekka Enberg wrote: > On Mon, 2009-04-20 at 23:20 +0100, Mel Gorman wrote: > > free_page_mlock() tests and clears PG_mlocked using locked versions of the > > bit operations. If set, it disables interrupts to update counters and this > > happens on every page free even though interrupts are disabled very shortly > > afterwards a second time. This is wasteful. > > > > This patch splits what free_page_mlock() does. The bit check is still > > made. However, the update of counters is delayed until the interrupts are > > disabled and the non-lock version for clearing the bit is used. One potential > > weirdness with this split is that the counters do not get updated if the > > bad_page() check is triggered but a system showing bad pages is getting > > screwed already. > > > > Signed-off-by: Mel Gorman > > Reviewed-by: Christoph Lameter > > Reviewed-by: Pekka Enberg > > > --- > > mm/internal.h | 11 +++-------- > > mm/page_alloc.c | 8 +++++++- > > 2 files changed, 10 insertions(+), 9 deletions(-) > > > > diff --git a/mm/internal.h b/mm/internal.h > > index 987bb03..58ec1bc 100644 > > --- a/mm/internal.h > > +++ b/mm/internal.h > > @@ -157,14 +157,9 @@ static inline void mlock_migrate_page(struct page *newpage, struct page *page) > > */ > > static inline void free_page_mlock(struct page *page) > > { > > - if (unlikely(TestClearPageMlocked(page))) { > > - unsigned long flags; > > - > > - local_irq_save(flags); > > - __dec_zone_page_state(page, NR_MLOCK); > > - __count_vm_event(UNEVICTABLE_MLOCKFREED); > > - local_irq_restore(flags); > > - } > > Maybe add a VM_BUG_ON(!PageMlocked(page))? > We always check in the caller and I don't see callers to this function expanding. I can add it if you insist but I don't think it'll catch anything in this case. > > + __ClearPageMlocked(page); > > + __dec_zone_page_state(page, NR_MLOCK); > > + __count_vm_event(UNEVICTABLE_MLOCKFREED); > > } > > > > #else /* CONFIG_HAVE_MLOCKED_PAGE_BIT */ > -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- 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: email@kvack.org