Commit 9f8f2172 authored by Christoph Lameter's avatar Christoph Lameter Committed by Linus Torvalds
Browse files

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: default avatarChristoph Lameter <clameter@sgi.com>
Acked-by: default avatarMel Gorman <mel@csn.ul.ie>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Daniel Walker <dwalker@mvista.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e2848a0e

include/linux/gfp.h

+2 −0
Original line number Diff line number Diff line
@@ -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 */

include/linux/suspend.h

+0 −1
Original line number Diff line number Diff line
@@ -130,7 +130,6 @@ struct pbe { 
};



/* mm/page_alloc.c */

extern void drain_local_pages(void);

extern void mark_free_pages(struct zone *zone);



/**

kernel/power/snapshot.c

+2 −2
Original line number Diff line number Diff line
@@ -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(&copy_bm, &orig_bm);



	/*

mm/memory_hotplug.c

+2 −4
Original line number Diff line number Diff line
@@ -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) {

mm/page_alloc.c

+42 −37
Original line number Diff line number Diff line
@@ -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;

}

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