From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: [merged] revert-mm-page_alloc-only-use-per-cpu-allocator-for-irq-safe-requests.patch removed from -mm tree Date: Tue, 25 Apr 2017 12:54:46 -0700 Message-ID: <20170425195446.cMVzYpaPt%akpm@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.linuxfoundation.org ([140.211.169.12]:46302 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1433165AbdDYTys (ORCPT ); Tue, 25 Apr 2017 15:54:48 -0400 Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: brouer@redhat.com, mgorman@techsingularity.net, mm-commits@vger.kernel.org, ttoukan.linux@gmail.com The patch titled Subject: Revert "mm, page_alloc: only use per-cpu allocator for irq-safe requests" has been removed from the -mm tree. Its filename was revert-mm-page_alloc-only-use-per-cpu-allocator-for-irq-safe-requests.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Mel Gorman Subject: Revert "mm, page_alloc: only use per-cpu allocator for irq-safe requests" This reverts 374ad05ab64. While the patch worked great for userspace allocations, the fact that softirq loses the per-cpu allocator caused problems. It needs to be redone taking into account that a separate list is needed for hard/soft IRQs or alternatively find a cheap way of detecting reentry due to an interrupt. Both are possible but sufficiently tricky that it shouldn't be rushed. Jesper had one method for allowing softirqs but reported that the cost was high enough that it performed similarly to a plain revert. His figures for netperf TCP_STREAM were as follows Baseline v4.10.0 : 60316 Mbit/s Current 4.11.0-rc6: 47491 Mbit/s Jesper's patch : 60662 Mbit/s This patch : 60106 Mbit/s As this is a regression, I wish to revert to noirq allocator for now and go back to the drawing board. Link: http://lkml.kernel.org/r/20170415145350.ixy7vtrzdzve57mh@techsingularity.net Signed-off-by: Mel Gorman Reported-by: Tariq Toukan Acked-by: Jesper Dangaard Brouer Signed-off-by: Andrew Morton --- mm/page_alloc.c | 43 ++++++++++++++++++++----------------------- 1 file changed, 20 insertions(+), 23 deletions(-) diff -puN mm/page_alloc.c~revert-mm-page_alloc-only-use-per-cpu-allocator-for-irq-safe-requests mm/page_alloc.c --- a/mm/page_alloc.c~revert-mm-page_alloc-only-use-per-cpu-allocator-for-irq-safe-requests +++ a/mm/page_alloc.c @@ -1090,10 +1090,10 @@ static void free_pcppages_bulk(struct zo { int migratetype = 0; int batch_free = 0; - unsigned long nr_scanned, flags; + unsigned long nr_scanned; bool isolated_pageblocks; - spin_lock_irqsave(&zone->lock, flags); + spin_lock(&zone->lock); isolated_pageblocks = has_isolate_pageblock(zone); nr_scanned = node_page_state(zone->zone_pgdat, NR_PAGES_SCANNED); if (nr_scanned) @@ -1142,7 +1142,7 @@ static void free_pcppages_bulk(struct zo trace_mm_page_pcpu_drain(page, 0, mt); } while (--count && --batch_free && !list_empty(list)); } - spin_unlock_irqrestore(&zone->lock, flags); + spin_unlock(&zone->lock); } static void free_one_page(struct zone *zone, @@ -1150,9 +1150,8 @@ static void free_one_page(struct zone *z unsigned int order, int migratetype) { - unsigned long nr_scanned, flags; - spin_lock_irqsave(&zone->lock, flags); - __count_vm_events(PGFREE, 1 << order); + unsigned long nr_scanned; + spin_lock(&zone->lock); 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); @@ -1162,7 +1161,7 @@ static void free_one_page(struct zone *z migratetype = get_pfnblock_migratetype(page, pfn); } __free_one_page(page, pfn, zone, order, migratetype); - spin_unlock_irqrestore(&zone->lock, flags); + spin_unlock(&zone->lock); } static void __meminit __init_single_page(struct page *page, unsigned long pfn, @@ -1240,6 +1239,7 @@ void __meminit reserve_bootmem_region(ph static void __free_pages_ok(struct page *page, unsigned int order) { + unsigned long flags; int migratetype; unsigned long pfn = page_to_pfn(page); @@ -1247,7 +1247,10 @@ static void __free_pages_ok(struct page return; migratetype = get_pfnblock_migratetype(page, pfn); + local_irq_save(flags); + __count_vm_events(PGFREE, 1 << order); 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) @@ -2219,9 +2222,8 @@ static int rmqueue_bulk(struct zone *zon int migratetype, bool cold) { int i, alloced = 0; - unsigned long flags; - spin_lock_irqsave(&zone->lock, flags); + spin_lock(&zone->lock); for (i = 0; i < count; ++i) { struct page *page = __rmqueue(zone, order, migratetype); if (unlikely(page == NULL)) @@ -2257,7 +2259,7 @@ static int rmqueue_bulk(struct zone *zon * pages added to the pcp list. */ __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order)); - spin_unlock_irqrestore(&zone->lock, flags); + spin_unlock(&zone->lock); return alloced; } @@ -2485,20 +2487,17 @@ void free_hot_cold_page(struct page *pag { struct zone *zone = page_zone(page); struct per_cpu_pages *pcp; + unsigned long flags; unsigned long pfn = page_to_pfn(page); int migratetype; - if (in_interrupt()) { - __free_pages_ok(page, 0); - return; - } - if (!free_pcp_prepare(page)) return; migratetype = get_pfnblock_migratetype(page, pfn); set_pcppage_migratetype(page, migratetype); - preempt_disable(); + local_irq_save(flags); + __count_vm_event(PGFREE); /* * We only track unmovable, reclaimable and movable on pcp lists. @@ -2515,7 +2514,6 @@ void free_hot_cold_page(struct page *pag migratetype = MIGRATE_MOVABLE; } - __count_vm_event(PGFREE); pcp = &this_cpu_ptr(zone->pageset)->pcp; if (!cold) list_add(&page->lru, &pcp->lists[migratetype]); @@ -2529,7 +2527,7 @@ void free_hot_cold_page(struct page *pag } out: - preempt_enable(); + local_irq_restore(flags); } /* @@ -2654,8 +2652,6 @@ static struct page *__rmqueue_pcplist(st { struct page *page; - VM_BUG_ON(in_interrupt()); - do { if (list_empty(list)) { pcp->count += rmqueue_bulk(zone, 0, @@ -2686,8 +2682,9 @@ static struct page *rmqueue_pcplist(stru struct list_head *list; bool cold = ((gfp_flags & __GFP_COLD) != 0); struct page *page; + unsigned long flags; - preempt_disable(); + local_irq_save(flags); pcp = &this_cpu_ptr(zone->pageset)->pcp; list = &pcp->lists[migratetype]; page = __rmqueue_pcplist(zone, migratetype, cold, pcp, list); @@ -2695,7 +2692,7 @@ static struct page *rmqueue_pcplist(stru __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order); zone_statistics(preferred_zone, zone); } - preempt_enable(); + local_irq_restore(flags); return page; } @@ -2711,7 +2708,7 @@ struct page *rmqueue(struct zone *prefer unsigned long flags; struct page *page; - if (likely(order == 0) && !in_interrupt()) { + if (likely(order == 0)) { page = rmqueue_pcplist(preferred_zone, zone, order, gfp_flags, migratetype); goto out; _ Patches currently in -mm which might be from mgorman@techsingularity.net are mm-vmscan-only-clear-pgdat-congested-dirty-writeback-state-when-balanced.patch mm-vmscan-prevent-kswapd-sleeping-prematurely-due-to-mismatched-classzone_idx.patch