lkml.org 
[lkml]   [2012]   [Jul]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
SubjectRe: [PATCH 3/3] mm: fix return value in __alloc_contig_migrate_range()
Date
Joonsoo Kim <js1304@gmail.com> writes:

> migrate_pages() would return positive value in some failure case,
> so 'ret > 0 ? 0 : ret' may be wrong.
> This fix it and remove one dead statement.
>
> Signed-off-by: Joonsoo Kim <js1304@gmail.com>
> Cc: Michal Nazarewicz <mina86@mina86.com>
> Cc: Marek Szyprowski <m.szyprowski@samsung.com>
> Cc: Minchan Kim <minchan@kernel.org>
> Cc: Christoph Lameter <cl@linux.com>

Have you actually encountered this problem? If migrate_pages() fails
with a positive value, the code that you are removing kicks in and
-EBUSY is assigned to ret (now that I look at it, I think that in the
current code the "return ret > 0 ? 0 : ret;" statement could be reduced
to "return ret;"). Your code seems to be cleaner, but the commit
message does not look accurate to me.

> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 4403009..02d4519 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5673,7 +5673,6 @@ static int __alloc_contig_migrate_range(unsigned long start, unsigned long end)
> }
> tries = 0;
> } else if (++tries == 5) {
> - ret = ret < 0 ? ret : -EBUSY;
> break;
> }
>
> @@ -5683,7 +5682,7 @@ static int __alloc_contig_migrate_range(unsigned long start, unsigned long end)
> }
>
> putback_lru_pages(&cc.migratepages);
> - return ret > 0 ? 0 : ret;
> + return ret <= 0 ? ret : -EBUSY;
> }
>
> /*

--
Best regards, _ _
.o. | Liege of Serenly Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michal "mina86" Nazarewicz (o o)
ooo +-<mina86-mina86.com>-<jid:mina86-jabber.org>--ooO--(_)--Ooo--
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2012-07-16 20:21    [W:0.201 / U:0.316 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site