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 ESMTP id 2CB689000C1 for ; Tue, 26 Apr 2011 08:31:14 -0400 (EDT) Date: Tue, 26 Apr 2011 22:30:59 +1000 From: NeilBrown Subject: Re: [PATCH 12/13] mm: Throttle direct reclaimers if PF_MEMALLOC reserves are low and swap is backed by network storage Message-ID: <20110426223059.10f3edda@notabene.brown> In-Reply-To: <1303803414-5937-13-git-send-email-mgorman@suse.de> References: <1303803414-5937-1-git-send-email-mgorman@suse.de> <1303803414-5937-13-git-send-email-mgorman@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Linux-MM , Linux-Netdev , LKML , David Miller , Peter Zijlstra On Tue, 26 Apr 2011 08:36:53 +0100 Mel Gorman wrote: > +/* > + * Throttle direct reclaimers if backing storage is backed by the network > + * and the PFMEMALLOC reserve for the preferred node is getting dangerously > + * depleted. kswapd will continue to make progress and wake the processes > + * when the low watermark is reached > + */ > +static void throttle_direct_reclaim(gfp_t gfp_mask, struct zonelist *zonelist, > + nodemask_t *nodemask) > +{ > + struct zone *zone; > + int high_zoneidx = gfp_zone(gfp_mask); > + DEFINE_WAIT(wait); > + > + /* Check if the pfmemalloc reserves are ok */ > + first_zones_zonelist(zonelist, high_zoneidx, NULL, &zone); > + prepare_to_wait(&zone->zone_pgdat->pfmemalloc_wait, &wait, > + TASK_INTERRUPTIBLE); > + if (pfmemalloc_watermark_ok(zone->zone_pgdat, high_zoneidx)) > + goto out; > + > + /* Throttle */ > + do { > + schedule(); > + finish_wait(&zone->zone_pgdat->pfmemalloc_wait, &wait); > + prepare_to_wait(&zone->zone_pgdat->pfmemalloc_wait, &wait, > + TASK_INTERRUPTIBLE); > + } while (!pfmemalloc_watermark_ok(zone->zone_pgdat, high_zoneidx) && > + !fatal_signal_pending(current)); > + > +out: > + finish_wait(&zone->zone_pgdat->pfmemalloc_wait, &wait); > +} You are doing an interruptible wait, but only checking for fatal signals. So if a non-fatal signal arrives, you will busy-wait. So I suspect you want TASK_KILLABLE, so just use: wait_event_killable(zone->zone_pgdat->pfmemalloc_wait, pgmemalloc_watermark_ok(zone->zone_pgdata, high_zoneidx)); (You also have an extraneous call to finish_wait) NeilBrown -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org