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Page allocator: clean up pcp draining functions

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- 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 <clameter@sgi.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Daniel Walker <dwalker@mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Christoph Lameter 2008-02-04 22:29:11 -08:00 committed by Linus Torvalds
parent e2848a0efe
commit 9f8f217253
5 changed files with 48 additions and 44 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/gfp.h
View File

@ -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 */

1
include/linux/suspend.h
View File

@ -130,7 +130,6 @@ struct pbe {
};
/* mm/page_alloc.c */
extern void drain_local_pages(void);
extern void mark_free_pages(struct zone *zone);
/**

4
kernel/power/snapshot.c
View File

@ -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);
/*

6
mm/memory_hotplug.c
View File

@ -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) {

79
mm/page_alloc.c
View File

@ -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;
}