On 16.1.2016 9:06, Sergey Senozhatsky wrote:
> On (01/16/16 08:44), Vlastimil Babka wrote:
>> On 16.1.2016 5:09, Sergey Senozhatsky wrote:
>>> On (01/15/16 16:49), Vlastimil Babka wrote:
>>
>> Hmm but that's an unpin, not a pin? A mistake or I'm missing something?
>
> I'm sure it's just a compose-in-mail-app typo.
BTW, couldn't the correct fix also just look like this?
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 9f15bdd9163c..43f743175ede 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -1635,8 +1635,8 @@ static int migrate_zspage(struct zs_pool *pool, struct
size_class *class,
free_obj = obj_malloc(d_page, class, handle);
zs_object_copy(free_obj, used_obj, class);
index++;
+ /* This also effectively unpins the handle */
record_obj(handle, free_obj);
- unpin_tag(handle);
obj_free(pool, class, used_obj);
}
But I'd still recommend WRITE_ONCE in record_obj(). And I'm not even sure it's
safe on all architectures to do a simple overwrite of a word against somebody
else trying to lock a bit there?
> -ss
>
>> Anyway the compiler can do the same thing here without a WRITE_ONCE().
>
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