From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id 345156B0047 for ; Tue, 9 Mar 2010 10:50:46 -0500 (EST) Date: Tue, 9 Mar 2010 09:50:15 -0600 (CST) From: Christoph Lameter Subject: Re: [PATCH 1/3] page-allocator: Under memory pressure, wait on pressure to relieve instead of congestion In-Reply-To: <1268048904-19397-2-git-send-email-mel@csn.ul.ie> Message-ID: References: <1268048904-19397-1-git-send-email-mel@csn.ul.ie> <1268048904-19397-2-git-send-email-mel@csn.ul.ie> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Mel Gorman Cc: linux-mm@kvack.org, Nick Piggin , Christian Ehrhardt , Chris Mason , Jens Axboe , linux-kernel@vger.kernel.org List-ID: On Mon, 8 Mar 2010, Mel Gorman wrote: > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > index 30fe668..72465c1 100644 > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -398,6 +398,9 @@ struct zone { > unsigned long wait_table_hash_nr_entries; > unsigned long wait_table_bits; > > + /* queue for processes waiting for pressure to relieve */ > + wait_queue_head_t *pressure_wq; > + > /* The waitqueue is in a zone? But allocation occurs by scanning a list of possible zones. > +long zonepressure_wait(struct zone *zone, unsigned int order, long timeout) So zone specific. > > - if (!page && gfp_mask & __GFP_NOFAIL) > - congestion_wait(BLK_RW_ASYNC, HZ/50); > + if (!page && gfp_mask & __GFP_NOFAIL) { > + /* If still failing, wait for pressure on zone to relieve */ > + zonepressure_wait(preferred_zone, order, HZ/50); The first zone is special therefore... What happens if memory becomes available in another zone? Lets say we are waiting on HIGHMEM and memory in ZONE_NORMAL becomes available? -- 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