From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752598AbdATPDB (ORCPT ); Fri, 20 Jan 2017 10:03:01 -0500 Received: from mx2.suse.de ([195.135.220.15]:33267 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752083AbdATPDA (ORCPT ); Fri, 20 Jan 2017 10:03:00 -0500 Subject: Re: [PATCH 4/4] mm, page_alloc: Only use per-cpu allocator for irq-safe requests To: Mel Gorman , Andrew Morton References: <20170117092954.15413-1-mgorman@techsingularity.net> <20170117092954.15413-5-mgorman@techsingularity.net> Cc: Linux Kernel , Linux-MM , Hillf Danton , Jesper Dangaard Brouer From: Vlastimil Babka Message-ID: <675145cb-e026-7ceb-ce96-446d3dd61fe0@suse.cz> Date: Fri, 20 Jan 2017 16:02:56 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.6.0 MIME-Version: 1.0 In-Reply-To: <20170117092954.15413-5-mgorman@techsingularity.net> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/17/2017 10:29 AM, Mel Gorman wrote: [...] > @@ -1244,10 +1243,8 @@ static void __free_pages_ok(struct page *page, unsigned int order) > return; > > migratetype = get_pfnblock_migratetype(page, pfn); > - local_irq_save(flags); > - __count_vm_events(PGFREE, 1 << order); > + count_vm_events(PGFREE, 1 << order); Maybe this could be avoided by moving the counting into free_one_page()? Diff suggestion at the end of e-mail. > free_one_page(page_zone(page), page, pfn, order, migratetype); > - local_irq_restore(flags); > } > > static void __init __free_pages_boot_core(struct page *page, unsigned int order) > @@ -2219,8 +2216,9 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order, > int migratetype, bool cold) > { > int i, alloced = 0; > + unsigned long flags; > > - spin_lock(&zone->lock); > + spin_lock_irqsave(&zone->lock, flags); > for (i = 0; i < count; ++i) { > struct page *page = __rmqueue(zone, order, migratetype); > if (unlikely(page == NULL)) > @@ -2256,7 +2254,7 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order, > * pages added to the pcp list. > */ > __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order)); > - spin_unlock(&zone->lock); > + spin_unlock_irqrestore(&zone->lock, flags); > return alloced; > } > > @@ -2472,16 +2470,20 @@ void free_hot_cold_page(struct page *page, bool cold) > { > struct zone *zone = page_zone(page); > struct per_cpu_pages *pcp; > - unsigned long flags; > unsigned long pfn = page_to_pfn(page); > int migratetype; > > if (!free_pcp_prepare(page)) > return; > > + if (in_interrupt()) { > + __free_pages_ok(page, 0); > + return; > + } I think this should go *before* free_pcp_prepare() otherwise free_pages_prepare() gets done twice in interrupt. diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 15b11fc0cd75..8c6f8a790272 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1149,6 +1149,7 @@ static void free_one_page(struct zone *zone, { unsigned long nr_scanned, flags; spin_lock_irqsave(&zone->lock, flags); + __count_vm_events(PGFREE, 1 << order); nr_scanned = node_page_state(zone->zone_pgdat, NR_PAGES_SCANNED); if (nr_scanned) __mod_node_page_state(zone->zone_pgdat, NR_PAGES_SCANNED, -nr_scanned); @@ -1243,7 +1244,6 @@ static void __free_pages_ok(struct page *page, unsigned int order) return; migratetype = get_pfnblock_migratetype(page, pfn); - count_vm_events(PGFREE, 1 << order); free_one_page(page_zone(page), page, pfn, order, migratetype); } @@ -2484,7 +2484,6 @@ void free_hot_cold_page(struct page *page, bool cold) migratetype = get_pfnblock_migratetype(page, pfn); set_pcppage_migratetype(page, migratetype); preempt_disable(); - __count_vm_event(PGFREE); /* * We only track unmovable, reclaimable and movable on pcp lists. @@ -2501,6 +2500,7 @@ void free_hot_cold_page(struct page *page, bool cold) migratetype = MIGRATE_MOVABLE; } + __count_vm_event(PGFREE); pcp = &this_cpu_ptr(zone->pageset)->pcp; if (!cold) list_add(&page->lru, &pcp->lists[migratetype]);