From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f199.google.com (mail-io0-f199.google.com [209.85.223.199]) by kanga.kvack.org (Postfix) with ESMTP id D4CBA6B0003 for ; Mon, 26 Feb 2018 16:53:13 -0500 (EST) Received: by mail-io0-f199.google.com with SMTP id n95so15941586ioo.2 for ; Mon, 26 Feb 2018 13:53:13 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id a31sor5476046itj.119.2018.02.26.13.53.12 for (Google Transport Security); Mon, 26 Feb 2018 13:53:13 -0800 (PST) Date: Mon, 26 Feb 2018 13:53:10 -0800 (PST) From: David Rientjes Subject: Re: [PATCH v3 2/3] mm/free_pcppages_bulk: do not hold lock when picking pages to free In-Reply-To: <20180226135346.7208-3-aaron.lu@intel.com> Message-ID: References: <20180226135346.7208-1-aaron.lu@intel.com> <20180226135346.7208-3-aaron.lu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Aaron Lu Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Huang Ying , Dave Hansen , Kemi Wang , Tim Chen , Andi Kleen , Michal Hocko , Vlastimil Babka , Mel Gorman , Matthew Wilcox On Mon, 26 Feb 2018, Aaron Lu wrote: > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 3154859cccd6..35576da0a6c9 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -1116,13 +1116,11 @@ static void free_pcppages_bulk(struct zone *zone, int count, > int migratetype = 0; > int batch_free = 0; > bool isolated_pageblocks; > + struct page *page, *tmp; > + LIST_HEAD(head); > > pcp->count -= count; > - spin_lock(&zone->lock); > - isolated_pageblocks = has_isolate_pageblock(zone); > - > while (count) { > - struct page *page; > struct list_head *list; > > /* > @@ -1144,26 +1142,31 @@ static void free_pcppages_bulk(struct zone *zone, int count, > batch_free = count; > > do { > - int mt; /* migratetype of the to-be-freed page */ > - > page = list_last_entry(list, struct page, lru); > /* must delete as __free_one_page list manipulates */ Looks good in general, but I'm not sure how I reconcile this comment with the new implementation that later links page->lru again. > list_del(&page->lru); > > - mt = get_pcppage_migratetype(page); > - /* MIGRATE_ISOLATE page should not go to pcplists */ > - VM_BUG_ON_PAGE(is_migrate_isolate(mt), page); > - /* Pageblock could have been isolated meanwhile */ > - if (unlikely(isolated_pageblocks)) > - mt = get_pageblock_migratetype(page); > - > if (bulkfree_pcp_prepare(page)) > continue; > > - __free_one_page(page, page_to_pfn(page), zone, 0, mt); > - trace_mm_page_pcpu_drain(page, 0, mt); > + list_add_tail(&page->lru, &head); > } while (--count && --batch_free && !list_empty(list)); > } > + > + spin_lock(&zone->lock); > + isolated_pageblocks = has_isolate_pageblock(zone); > + > + list_for_each_entry_safe(page, tmp, &head, lru) { > + int mt = get_pcppage_migratetype(page); > + /* MIGRATE_ISOLATE page should not go to pcplists */ > + VM_BUG_ON_PAGE(is_migrate_isolate(mt), page); > + /* Pageblock could have been isolated meanwhile */ > + if (unlikely(isolated_pageblocks)) > + mt = get_pageblock_migratetype(page); > + > + __free_one_page(page, page_to_pfn(page), zone, 0, mt); > + trace_mm_page_pcpu_drain(page, 0, mt); > + } > spin_unlock(&zone->lock); > } > -- 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