Messages in this thread | | | Subject | Re: [PATCH v9 07/20] mm/lru: introduce TestClearPageLRU | From | Alex Shi <> | Date | Tue, 3 Mar 2020 12:11:34 +0800 |
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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 https://git.kernel.org/pub/scm/linux/kernel/git/wfg/vm-scalability.git/ which is most sensitive case on PageLRU I found. There are no clear performance drop.
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! Alex
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