Re: [PATCH 1/3] mm: correct return value of migrate_pages()

From: JoonSoo Kim
Date: Mon Jul 16 2012 - 13:32:04 EST


2012/7/17 Christoph Lameter <cl@xxxxxxxxx>:
> On Tue, 17 Jul 2012, Joonsoo Kim wrote:
>
>> migrate_pages() should return number of pages not migrated or error code.
>> When unmap_and_move return -EAGAIN, outer loop is re-execution without
>> initialising nr_failed. This makes nr_failed over-counted.
>
> The itention of the nr_failed was only to give an indication as to how
> many attempts where made. The failed pages where on a separate queue that
> seems to have vanished.
>
>> So this patch correct it by initialising nr_failed in outer loop.
>
> Well yea it makes sense since retry is initialized there as well.
>
> Acked-by: Christoph Lameter <cl@xxxxxxxxx>

Thanks for comment.

Additinally, I find that migrate_huge_pages() is needed identical fix
as migrate_pages().

@@ -1029,6 +1030,7 @@ int migrate_huge_pages(struct list_head *from,

for (pass = 0; pass < 10 && retry; pass++) {
retry = 0;
+ nr_failed = 0;

list_for_each_entry_safe(page, page2, from, lru) {
cond_resched();

When I resend with this, could I include "Acked-by: Christoph Lameter
<cl@xxxxxxxxx>"?
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