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.
