linux-kernel - Re: [PATCH v3 4/4] mm: Remove managed_page

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Message-ID: <e3ca027726d9683a9fbf3694a96afd17@codeaurora.org>
Date:   Thu, 08 Nov 2018 16:01:10 +0530
From:   Arun KS <arunks@...eaurora.org>
To:     Michal Hocko <mhocko@...nel.org>
Cc:     akpm@...ux-foundation.org, keescook@...omium.org,
        khlebnikov@...dex-team.ru, minchan@...nel.org, vbabka@...e.cz,
        osalvador@...e.de, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, getarunks@...il.com
Subject: Re: [PATCH v3 4/4] mm: Remove managed_page_count spinlock

On 2018-11-08 15:44, Michal Hocko wrote:
> On Thu 08-11-18 15:33:06, Arun KS wrote:
>> On 2018-11-08 14:04, Michal Hocko wrote:
>> > On Thu 08-11-18 13:53:18, Arun KS wrote:
>> > > Now totalram_pages and managed_pages are atomic varibles. No need
>> > > of managed_page_count spinlock.
>> >
>> > As explained earlier. Please add a motivation here. Feel free to reuse
>> > wording from
>> > http://lkml.kernel.org/r/20181107103630.GF2453@dhcp22.suse.cz
>> 
>> Sure. Will add in next spin.
> 
> Andrew usually updates changelogs if you give him the full wording.
> I would wait few days before resubmitting, if that is needed at all.

mm: Remove managed_page_count spinlock

Now that totalram_pages and managed_pages are atomic varibles, no need
of managed_page_count spinlock. The lock had really a weak consistency
guarantee. It hasn't been used for anything but the update but no reader
actually cares about all the values being updated to be in sync.

Signed-off-by: Arun KS <arunks@...eaurora.org>
Reviewed-by: Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
Acked-by: Michal Hocko <mhocko@...e.com>
Acked-by: Vlastimil Babka <vbabka@...e.cz>


> 0day will throw a lot of random configs which can reveal some 
> leftovers.

Yea. Fixed few of them during v3.

Regards,
Arun