From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751938AbdHSKFl (ORCPT ); Sat, 19 Aug 2017 06:05:41 -0400 Received: from mga03.intel.com ([134.134.136.65]:43239 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750854AbdHSKFk (ORCPT ); Sat, 19 Aug 2017 06:05:40 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.41,396,1498546800"; d="scan'208";a="1164215324" Date: Sat, 19 Aug 2017 18:07:21 +0800 From: Chen Yu To: Michal Hocko Cc: linux-mm@kvack.org, Andrew Morton , Mel Gorman , Vlastimil Babka , "Rafael J. Wysocki" , Len Brown , Dan Williams , linux-kernel@vger.kernel.org Subject: Re: [PATCH][RFC v3] PM / Hibernate: Feed the wathdog when creating snapshot Message-ID: <20170819100721.GA18859@yu-desktop-1.sh.intel.com> References: <1502942674-25773-1-git-send-email-yu.c.chen@intel.com> <20170817112806.GD17781@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170817112806.GD17781@dhcp22.suse.cz> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 17, 2017 at 01:28:06PM +0200, Michal Hocko wrote: > On Thu 17-08-17 12:04:34, Chen Yu wrote: > [...] > > #ifdef CONFIG_HIBERNATION > > > > +/* Touch watchdog for every WD_INTERVAL_PAGE pages. */ > > +#define WD_INTERVAL_PAGE 1000 > > traversing 1000 pages should never take too much time so this could be > overly aggressive. 100k pages could be acceptable as well. But I haven't > measure that so I might be easily wrong here. So this is just my 2c > After checking the log: [ 1144.690405] done (allocated 6590003 pages) [ 1144.694971] PM: Allocated 26360012 kbytes in 19.89 seconds (1325.28 MB/s) The default NMI timeout is 10 seconds AFAIK, in case the user might modify it to 1 second, a safe interval page could be 6590003/20 = 320k pages, but there might be other machines running in a lower freq, 100k should be more robust. I'll change it to 100k. > > + > > void mark_free_pages(struct zone *zone) > > { > > unsigned long pfn, max_zone_pfn; > > unsigned long flags; > > - unsigned int order, t; > > + unsigned int order, t, page_num = 0; > > struct page *page; > > > > if (zone_is_empty(zone)) > > @@ -2548,6 +2552,9 @@ void mark_free_pages(struct zone *zone) > > if (pfn_valid(pfn)) { > > page = pfn_to_page(pfn); > > > > + if (!((page_num++) % WD_INTERVAL_PAGE)) > > + touch_nmi_watchdog(); > > + > > if (page_zone(page) != zone) > > continue; > > > > @@ -2555,14 +2562,19 @@ void mark_free_pages(struct zone *zone) > > swsusp_unset_page_free(page); > > } > > > > + page_num = 0; > > + > > this part doesn't make much sense to me. You are still inside the same > IRQ disabled section. So why would you want to start counting from 0 > again. Not that this would make any difference in real life but the code > is not logical > Ok, will delete this. > > for_each_migratetype_order(order, t) { > > list_for_each_entry(page, > > &zone->free_area[order].free_list[t], lru) { > > unsigned long i; > > > > pfn = page_to_pfn(page); > > - for (i = 0; i < (1UL << order); i++) > > + for (i = 0; i < (1UL << order); i++) { > > + if (!((page_num++) % WD_INTERVAL_PAGE)) > > + touch_nmi_watchdog(); > > swsusp_set_page_free(pfn_to_page(pfn + i)); > > + } > > } > > } > > spin_unlock_irqrestore(&zone->lock, flags); > > -- > > 2.7.4 > > -- > Michal Hocko > SUSE Labs Thanks, Yu