On 01/21/2015 08:59 PM, Joonsoo Kim wrote:
> On Tue, Jan 20, 2015 at 11:31:43PM -0500, Sasha Levin wrote:
>> > Commit "mm/slub: optimize alloc/free fastpath by removing preemption
>> > on/off"
>> > has added access to percpu memory while the code is preemptible.
>> >
>> > While those accesses are okay, this creates a huge amount of warnings from
>> > the code that checks for that.
>> >
>> > Signed-off-by: Sasha Levin <sasha.le...@oracle.com>
> Hello,
>
> I already sent the patch to fix this issue and it is in mmotm, but,
> not be released yet.
>
> https://lkml.org/lkml/2015/1/19/17
The patch you sent out still has the issue. The one I sent goes on top of
it.
+ do {
+ tid = this_cpu_read(s->cpu_slab->tid); <=== checked percpu
access
+ c = raw_cpu_ptr(s->cpu_slab);
+ } while (IS_ENABLED(CONFIG_PREEMPT) && unlikely(tid != c->tid));
Thanks,
Sasha
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