From: Arun KS <arunks@codeaurora.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: arunks.linux@gmail.com, akpm@linux-foundation.org,
vbabka@suse.cz, osalvador@suse.de, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, getarunks@gmail.com
Subject: Re: [PATCH v6 1/2] memory_hotplug: Free pages as higher order
Date: Tue, 06 Nov 2018 21:01:29 +0530 [thread overview]
Message-ID: <542cd3516b54d88d1bffede02c6045b8@codeaurora.org> (raw)
In-Reply-To: <20181106140638.GN27423@dhcp22.suse.cz>
On 2018-11-06 19:36, Michal Hocko wrote:
> On Tue 06-11-18 11:33:13, Arun KS wrote:
>> When free pages are done with higher order, time spend on
>> coalescing pages by buddy allocator can be reduced. With
>> section size of 256MB, hot add latency of a single section
>> shows improvement from 50-60 ms to less than 1 ms, hence
>> improving the hot add latency by 60%. Modify external
>> providers of online callback to align with the change.
>>
>> This patch modifies totalram_pages, zone->managed_pages and
>> totalhigh_pages outside managed_page_count_lock. A follow up
>> series will be send to convert these variable to atomic to
>> avoid readers potentially seeing a store tear.
>
> Is there any reason to rush this through rather than wait for counters
> conversion first?
Sure Michal.
Conversion patch, https://patchwork.kernel.org/cover/10657217/ is
currently incremental to this patch. I ll change the order. Will wait
for preparatory patch to settle first.
Regards,
Arun.
>
> The patch as is looks good to me - modulo atomic counters of course. I
> cannot really judge whether existing updaters do really race in
> practice
> to take this riskless.
>
> The improvement is nice of course but this is a rare operation and 50ms
> vs 1ms is hardly noticeable. So I would rather wait for the preparatory
> work to settle. Btw. is there anything blocking that? It seems to be
> mostly automated.
next prev parent reply other threads:[~2018-11-06 15:31 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-06 6:03 [PATCH v6 1/2] memory_hotplug: Free pages as higher order Arun KS
2018-11-06 6:03 ` [PATCH v6 2/2] mm/page_alloc: remove software prefetching in __free_pages_core Arun KS
2018-11-06 14:08 ` Michal Hocko
2018-11-06 14:06 ` [PATCH v6 1/2] memory_hotplug: Free pages as higher order Michal Hocko
2018-11-06 15:31 ` Arun KS [this message]
2018-11-06 20:08 ` Michal Hocko
2018-11-07 6:21 ` Arun KS
2019-01-04 5:05 ` Arun KS
2019-01-04 8:58 ` Michal Hocko
2019-01-04 9:01 ` Arun Sudhilal
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