From 9f8f2172537de7af0b0fbd33502d18d52b1339bc Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Mon, 4 Feb 2008 22:29:11 -0800 Subject: [PATCH] Page allocator: clean up pcp draining functions - Add comments explaing how drain_pages() works. - Eliminate useless functions - Rename drain_all_local_pages to drain_all_pages(). It does drain all pages not only those of the local processor. - Eliminate useless interrupt off / on sequences. drain_pages() disables interrupts on its own. The execution thread is pinned to processor by the caller. So there is no need to disable interrupts. - Put drain_all_pages() declaration in gfp.h and remove the declarations from suspend.h and from mm/memory_hotplug.c - Make software suspend call drain_all_pages(). The draining of processor local pages is may not the right approach if software suspend wants to support SMP. If they call drain_all_pages then we can make drain_pages() static. [akpm@linux-foundation.org: fix build] Signed-off-by: Christoph Lameter Acked-by: Mel Gorman Cc: "Rafael J. Wysocki" Cc: Daniel Walker Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/gfp.h | 2 ++ include/linux/suspend.h | 1 - kernel/power/snapshot.c | 4 +-- mm/memory_hotplug.c | 6 ++-- mm/page_alloc.c | 79 ++++++++++++++++++++++------------------- 5 files changed, 48 insertions(+), 44 deletions(-) diff --git a/include/linux/gfp.h b/include/linux/gfp.h index 7e93a9ae706..0c6ce515185 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -228,5 +228,7 @@ extern void FASTCALL(free_cold_page(struct page *page)); void page_alloc_init(void); void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp); +void drain_all_pages(void); +void drain_local_pages(void *dummy); #endif /* __LINUX_GFP_H */ diff --git a/include/linux/suspend.h b/include/linux/suspend.h index 646ce2d068d..1d7d4c5797e 100644 --- a/include/linux/suspend.h +++ b/include/linux/suspend.h @@ -130,7 +130,6 @@ struct pbe { }; /* mm/page_alloc.c */ -extern void drain_local_pages(void); extern void mark_free_pages(struct zone *zone); /** diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index f6a5df934f8..95250d7c8d9 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -1203,7 +1203,7 @@ asmlinkage int swsusp_save(void) printk(KERN_INFO "PM: Creating hibernation image: \n"); - drain_local_pages(); + drain_local_pages(NULL); nr_pages = count_data_pages(); nr_highmem = count_highmem_pages(); printk(KERN_INFO "PM: Need to copy %u pages\n", nr_pages + nr_highmem); @@ -1221,7 +1221,7 @@ asmlinkage int swsusp_save(void) /* During allocating of suspend pagedir, new cold pages may appear. * Kill them. */ - drain_local_pages(); + drain_local_pages(NULL); copy_data_pages(©_bm, &orig_bm); /* diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 9512a544d04..7469c503580 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -481,8 +481,6 @@ check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) return offlined; } -extern void drain_all_local_pages(void); - int offline_pages(unsigned long start_pfn, unsigned long end_pfn, unsigned long timeout) { @@ -540,7 +538,7 @@ repeat: lru_add_drain_all(); flush_scheduled_work(); cond_resched(); - drain_all_local_pages(); + drain_all_pages(); } pfn = scan_lru_pages(start_pfn, end_pfn); @@ -563,7 +561,7 @@ repeat: flush_scheduled_work(); yield(); /* drain pcp pages , this is synchrouns. */ - drain_all_local_pages(); + drain_all_pages(); /* check again */ offlined_pages = check_pages_isolated(start_pfn, end_pfn); if (offlined_pages < 0) { diff --git a/mm/page_alloc.c b/mm/page_alloc.c index b2838c24e58..5c7de8e959f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -890,7 +890,14 @@ void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp) } #endif -static void __drain_pages(unsigned int cpu) +/* + * Drain pages of the indicated processor. + * + * The processor must either be the current processor and the + * thread pinned to the current processor or a processor that + * is not online. + */ +static void drain_pages(unsigned int cpu) { unsigned long flags; struct zone *zone; @@ -915,6 +922,22 @@ static void __drain_pages(unsigned int cpu) } } +/* + * Spill all of this CPU's per-cpu pages back into the buddy allocator. + */ +void drain_local_pages(void *arg) +{ + drain_pages(smp_processor_id()); +} + +/* + * Spill all the per-cpu pages from all CPUs back into the buddy allocator + */ +void drain_all_pages(void) +{ + on_each_cpu(drain_local_pages, NULL, 0, 1); +} + #ifdef CONFIG_HIBERNATION void mark_free_pages(struct zone *zone) @@ -951,37 +974,6 @@ void mark_free_pages(struct zone *zone) } #endif /* CONFIG_PM */ -/* - * Spill all of this CPU's per-cpu pages back into the buddy allocator. - */ -void drain_local_pages(void) -{ - unsigned long flags; - - local_irq_save(flags); - __drain_pages(smp_processor_id()); - local_irq_restore(flags); -} - -void smp_drain_local_pages(void *arg) -{ - drain_local_pages(); -} - -/* - * Spill all the per-cpu pages from all CPUs back into the buddy allocator - */ -void drain_all_local_pages(void) -{ - unsigned long flags; - - local_irq_save(flags); - __drain_pages(smp_processor_id()); - local_irq_restore(flags); - - smp_call_function(smp_drain_local_pages, NULL, 0, 1); -} - /* * Free a 0-order page */ @@ -1569,7 +1561,7 @@ nofail_alloc: cond_resched(); if (order != 0) - drain_all_local_pages(); + drain_all_pages(); if (likely(did_some_progress)) { page = get_page_from_freelist(gfp_mask, order, @@ -3978,10 +3970,23 @@ static int page_alloc_cpu_notify(struct notifier_block *self, int cpu = (unsigned long)hcpu; if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) { - local_irq_disable(); - __drain_pages(cpu); + drain_pages(cpu); + + /* + * Spill the event counters of the dead processor + * into the current processors event counters. + * This artificially elevates the count of the current + * processor. + */ vm_events_fold_cpu(cpu); - local_irq_enable(); + + /* + * Zero the differential counters of the dead processor + * so that the vm statistics are consistent. + * + * This is only okay since the processor is dead and cannot + * race with what we are doing. + */ refresh_cpu_vm_stats(cpu); } return NOTIFY_OK; @@ -4480,7 +4485,7 @@ int set_migratetype_isolate(struct page *page) out: spin_unlock_irqrestore(&zone->lock, flags); if (!ret) - drain_all_local_pages(); + drain_all_pages(); return ret; } -- 2.41.1