[lkml]   [2020]   [Mar]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH v9 07/20] mm/lru: introduce TestClearPageLRU

在 2020/3/3 上午6:11, Andrew Morton 写道:
>> - if (PageLRU(page)) {
>> + if (TestClearPageLRU(page)) {
>> lruvec = mem_cgroup_page_lruvec(page, pgdat);
>> - ClearPageLRU(page);
>> del_page_from_lru_list(page, lruvec, page_lru(page));
>> } else
> The code will now get exclusive access of the page->flags cacheline and
> will dirty that cacheline, even for !PageLRU() pages. What is the
> performance impact of this?

Hi Andrew,

Thanks a lot for comments!

I was tested the whole patchset with fengguang's case-lru-file-readtwice
which is most sensitive case on PageLRU I found. There are no clear performance

On this single patch, I just test the same case again, there is still no perf
drop. some data is here on my 96 threads machine:

no lock_dep w lock_dep and few other debug option
w this patch, 50.96MB/s 32.93MB/s
w/o this patch, 50.50MB/s 33.53MB/s

And also no any warning from Intel 0day yet.

Thanks a lot!

 \ /
  Last update: 2020-03-03 05:13    [W:0.070 / U:3.804 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site