Messages in this thread |  | | Subject | Re: [PATCH] mm: thp: don't need drain lru cache when splitting and mlocking THP | From | Yang Shi <> | Date | Thu, 2 Apr 2020 16:14:44 -0700 |
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On 4/2/20 4:04 PM, Daniel Jordan wrote: > On Sat, Mar 28, 2020 at 03:29:40AM +0800, Yang Shi wrote: >> Since the commit 8f182270dfec ("mm/swap.c: flush lru pvecs on compound >> page arrival") THP would not stay in pagevec anymore. So the >> optimization made by commit d965432234db ("thp: increase >> split_huge_page() success rate") doesn't make sense anymore, which tries >> to unpin munlocked THPs from pagevec by draining pagevec. >> >> And draining lru cache before isolating THP in mlock path is unnecessary >> either. > Can we get some of that nice history in this part too? > > Draining lru cache before isolating THP in mlock path is also unnecessary. > b676b293fb48 ("mm, thp: fix mapped pages avoiding unevictable list on mlock") > added it and 9a73f61bdb8a ("thp, mlock: do not mlock PTE-mapped file huge > pages") accidentally carried it over after the above optimization went in.
Thanks for finding out this, I didn't dig that far. Will add it into v2.
> >> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> >> Cc: Hugh Dickins <hughd@google.com> >> Cc: Andrea Arcangeli <aarcange@redhat.com> >> Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> > Since we don't mlock pte-mapped THP, it seems these huge pages wouldn't ever be > in the pagevecs if I'm understanding it all.
Yes, it is correct.
> > Saves lines and some amount of overhead and lru contention, so looks good. > > Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Thanks.
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