> On Sep 9, 2016, at 07:26, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> On Wed, 07 Sep 2016 08:41:26 +0800 Li Zhong <zhong@xxxxxxxxxxxxxxxxxx> wrote:
>
>> Warn about allocating with an empty nodemask, it would be easier to
>> understand than oom messages. The check is added in the slow path.
>>
>> Suggested-by: Vlastimil Babka <vbabka@xxxxxxx>
>> Signed-off-by: Li Zhong <zhong@xxxxxxxxxxxxxxxxxx>
>> ---
>> mm/page_alloc.c | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>> index a2214c6..d624ff3 100644
>> --- a/mm/page_alloc.c
>> +++ b/mm/page_alloc.c
>> @@ -3448,6 +3448,12 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
>> if (page)
>> goto got_pg;
>>
>> + if (ac->nodemask && nodes_empty(*ac->nodemask)) {
>> + pr_warn("nodemask is empty\n");
>> + gfp_mask &= ~__GFP_NOWARN;
>> + goto nopage;
>> + }
>> +
>
> Wouldn't it be better to do
>
> if (WARN_ON(ac->nodemask && nodes_empty(*ac->nodemask)) {
> ...
>
> so we can identify the misbehaving call site?
I think with __GFP_NOWARN cleared, we could know the call site from warn_alloc_failed().
And the message “nodemask is empty” makes the error obvious without going to the source.
Thanks, Zhong
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href