* [patch] mm, page_alloc: set num_movable in move_freepages()
@ 2018-10-05 20:56 David Rientjes
2018-10-05 21:21 ` Andrew Morton
0 siblings, 1 reply; 4+ messages in thread
From: David Rientjes @ 2018-10-05 20:56 UTC (permalink / raw)
To: Andrew Morton; +Cc: Vlastimil Babka, Greg Thelen, linux-kernel, linux-mm
If move_freepages() returns 0 because zone_spans_pfn(), *num_movable can
hold the value from the stack because it does not get initialized in
move_freepages().
Move the initialization to move_freepages_block() to guarantee the value
actually makes sense.
This currently doesn't affect its only caller where num_movable != NULL,
so no bug fix, but just more robust.
Signed-off-by: David Rientjes <rientjes@google.com>
---
mm/page_alloc.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2015,10 +2015,6 @@ static int move_freepages(struct zone *zone,
pfn_valid(page_to_pfn(end_page)) &&
page_zone(start_page) != page_zone(end_page));
#endif
-
- if (num_movable)
- *num_movable = 0;
-
for (page = start_page; page <= end_page;) {
if (!pfn_valid_within(page_to_pfn(page))) {
page++;
@@ -2058,6 +2054,9 @@ int move_freepages_block(struct zone *zone, struct page *page,
unsigned long start_pfn, end_pfn;
struct page *start_page, *end_page;
+ if (num_movable)
+ *num_movable = 0;
+
start_pfn = page_to_pfn(page);
start_pfn = start_pfn & ~(pageblock_nr_pages-1);
start_page = pfn_to_page(start_pfn);
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [patch] mm, page_alloc: set num_movable in move_freepages()
2018-10-05 20:56 [patch] mm, page_alloc: set num_movable in move_freepages() David Rientjes
@ 2018-10-05 21:21 ` Andrew Morton
2018-10-07 22:35 ` David Rientjes
2018-10-16 12:24 ` Vlastimil Babka
0 siblings, 2 replies; 4+ messages in thread
From: Andrew Morton @ 2018-10-05 21:21 UTC (permalink / raw)
To: David Rientjes; +Cc: Vlastimil Babka, Greg Thelen, linux-kernel, linux-mm
On Fri, 5 Oct 2018 13:56:39 -0700 (PDT) David Rientjes <rientjes@google.com> wrote:
> If move_freepages() returns 0 because zone_spans_pfn(), *num_movable can
move_free_pages_block()? !zone_spans_pfn()?
> hold the value from the stack because it does not get initialized in
> move_freepages().
>
> Move the initialization to move_freepages_block() to guarantee the value
> actually makes sense.
>
> This currently doesn't affect its only caller where num_movable != NULL,
> so no bug fix, but just more robust.
>
> ...
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [patch] mm, page_alloc: set num_movable in move_freepages()
2018-10-05 21:21 ` Andrew Morton
@ 2018-10-07 22:35 ` David Rientjes
2018-10-16 12:24 ` Vlastimil Babka
1 sibling, 0 replies; 4+ messages in thread
From: David Rientjes @ 2018-10-07 22:35 UTC (permalink / raw)
To: Andrew Morton; +Cc: Vlastimil Babka, Greg Thelen, linux-kernel, linux-mm
On Fri, 5 Oct 2018, Andrew Morton wrote:
> On Fri, 5 Oct 2018 13:56:39 -0700 (PDT) David Rientjes <rientjes@google.com> wrote:
>
> > If move_freepages() returns 0 because zone_spans_pfn(), *num_movable can
>
> move_free_pages_block()? !zone_spans_pfn()?
>
move_freepages_block() more accurately, yes. And yes, it depends on the
return value of zone_spans_pfn().
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [patch] mm, page_alloc: set num_movable in move_freepages()
2018-10-05 21:21 ` Andrew Morton
2018-10-07 22:35 ` David Rientjes
@ 2018-10-16 12:24 ` Vlastimil Babka
1 sibling, 0 replies; 4+ messages in thread
From: Vlastimil Babka @ 2018-10-16 12:24 UTC (permalink / raw)
To: Andrew Morton, David Rientjes; +Cc: Greg Thelen, linux-kernel, linux-mm
On 10/5/18 11:21 PM, Andrew Morton wrote:
> On Fri, 5 Oct 2018 13:56:39 -0700 (PDT) David Rientjes <rientjes@google.com> wrote:
>
>> If move_freepages() returns 0 because zone_spans_pfn(), *num_movable can
>
> move_free_pages_block()? !zone_spans_pfn()?
Also the subject would be more accurate if it said "initialize
num_movable in move_freepages_block()" ?
Otherwise,
Acked-by: Vlastimil Babka <vbabka@suse.cz>
>> hold the value from the stack because it does not get initialized in
>> move_freepages().
>>
>> Move the initialization to move_freepages_block() to guarantee the value
>> actually makes sense.
>>
>> This currently doesn't affect its only caller where num_movable != NULL,
>> so no bug fix, but just more robust.
>>
>> ...
>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2018-10-16 12:24 UTC | newest]
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2018-10-05 20:56 [patch] mm, page_alloc: set num_movable in move_freepages() David Rientjes
2018-10-05 21:21 ` Andrew Morton
2018-10-07 22:35 ` David Rientjes
2018-10-16 12:24 ` Vlastimil Babka
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