Subject: Re: [PATCH v6] hugetlb: Add hugetlb.*.numa_stat file
To: Muchun Song <songmuchun@xxxxxxxxxxxxx>, Mina Almasry <almasrymina@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>, Shuah Khan <shuah@xxxxxxxxxx>, Miaohe Lin <linmiaohe@xxxxxxxxxx>, Oscar Salvador <osalvador@xxxxxxx>, Michal Hocko <mhocko@xxxxxxxx>, David Rientjes <rientjes@xxxxxxxxxx>, Shakeel Butt <shakeelb@xxxxxxxxxx>, Jue Wang <juew@xxxxxxxxxx>, Yang Yao <ygyao@xxxxxxxxxx>, Joanna Li <joannali@xxxxxxxxxx>, Cannon Matthews <cannonmatthews@xxxxxxxxxx>, Linux Memory Management List <linux-mm@xxxxxxxxx>, LKML <linux-kernel@xxxxxxxxxxxxxxx>
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-=-=-=-=-=-=-=-=-=# Don't remove this line #=-=-=-=-=-=-=-=-=-
On 11/10/21 6:36 PM, Muchun Song wrote:
> On Thu, Nov 11, 2021 at 9:50 AM Mina Almasry <almasrymina@xxxxxxxxxx> wrote:
>>
>> +struct hugetlb_cgroup_per_node {
>> + /* hugetlb usage in pages over all hstates. */
>> + atomic_long_t usage[HUGE_MAX_HSTATE];
>
> Why do you use atomic? IIUC, 'usage' is always
> increased/decreased under hugetlb_lock except
> hugetlb_cgroup_read_numa_stat() which is always
> reading it. So I think WRITE_ONCE/READ_ONCE
> is enough.
Thanks for continuing to work this, I was traveling and unable to
comment.
Unless I am missing something, I do not see a reason for WRITE_ONCE/READ_ONCE
and would suggest going back to the way this code was in v5.
--
Mike Kravetz
