The patch titled
Subject: mm/thp: simplify lru_add_page_tail()
has been added to the -mm tree. Its filename is
mm-thp-simplify-lru_add_page_tail.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-thp-simplify-lru_add_page_tail.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-thp-simplify-lru_add_page_tail.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Subject: mm/thp: simplify lru_add_page_tail()
Simplify lru_add_page_tail(), there are actually only two cases possible:
split_huge_page_to_list(), with list supplied and head isolated from lru
by its caller; or split_huge_page(), with NULL list and head on lru -
because when head is racily isolated from lru, the isolator's reference
will stop the split from getting any further than its page_ref_freeze().
So decide between the two cases by "list", but add VM_WARN_ON()s to
verify that they match our lru expectations.
[Hugh Dickins: rewrite commit log]
Link: https://lkml.kernel.org/r/1604566549-62481-4-git-send-email-alex.shi@xxxxxxxxxxxxxxxxx
Signed-off-by: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Acked-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Mika Penttilä <mika.penttila@xxxxxxxxxxxx>
Cc: Alexander Duyck <alexander.duyck@xxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: "Chen, Rong A" <rong.a.chen@xxxxxxxxx>
Cc: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
Cc: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
Cc: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Wei Yang <richard.weiyang@xxxxxxxxx>
Cc: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 20 ++++++--------------
1 file changed, 6 insertions(+), 14 deletions(-)
--- a/mm/huge_memory.c~mm-thp-simplify-lru_add_page_tail
+++ a/mm/huge_memory.c
@@ -2353,24 +2353,16 @@ static void lru_add_page_tail(struct pag
VM_BUG_ON_PAGE(PageLRU(tail), head);
lockdep_assert_held(&lruvec_pgdat(lruvec)->lru_lock);
- if (!list)
- SetPageLRU(tail);
-
- if (likely(PageLRU(head)))
- list_add_tail(&tail->lru, &head->lru);
- else if (list) {
+ if (list) {
/* page reclaim is reclaiming a huge page */
+ VM_WARN_ON(PageLRU(head));
get_page(tail);
list_add_tail(&tail->lru, list);
} else {
- /*
- * Head page has not yet been counted, as an hpage,
- * so we must account for each subpage individually.
- *
- * Put tail on the list at the correct position
- * so they all end up in order.
- */
- add_page_to_lru_list_tail(tail, lruvec, page_lru(tail));
+ /* head is still on lru (and we have it frozen) */
+ VM_WARN_ON(!PageLRU(head));
+ SetPageLRU(tail);
+ list_add_tail(&tail->lru, &head->lru);
}
}
_
Patches currently in -mm which might be from alex.shi@xxxxxxxxxxxxxxxxx are
mm-filemap-add-static-for-function-__add_to_page_cache_locked.patch
fs-ntfs-remove-unused-varibles.patch
fs-ntfs-remove-unused-varible-attr_len.patch
mm-memcg-update-page-struct-member-in-comments.patch
mm-thp-move-lru_add_page_tail-func-to-huge_memoryc.patch
mm-thp-use-head-for-head-page-in-lru_add_page_tail.patch
mm-thp-simplify-lru_add_page_tail.patch
mm-thp-narrow-lru-locking.patch
mm-vmscan-remove-unnecessary-lruvec-adding.patch
mm-rmap-stop-store-reordering-issue-on-page-mapping.patch
mm-rmap-stop-store-reordering-issue-on-page-mapping-fix.patch
mm-memcg-add-debug-checking-in-lock_page_memcg.patch
mm-swapc-fold-vm-event-pgrotated-into-pagevec_move_tail_fn.patch
mm-lru-move-lock-into-lru_note_cost.patch
mm-vmscan-remove-lruvec-reget-in-move_pages_to_lru.patch
mm-mlock-remove-lru_lock-on-testclearpagemlocked.patch
mm-mlock-remove-__munlock_isolate_lru_page.patch
mm-lru-introduce-testclearpagelru.patch
mm-compaction-do-page-isolation-first-in-compaction.patch
mm-swapc-serialize-memcg-changes-in-pagevec_lru_move_fn.patch
mm-lru-replace-pgdat-lru_lock-with-lruvec-lock.patch
mm-lru-replace-pgdat-lru_lock-with-lruvec-lock-fix.patch
mm-lru-replace-pgdat-lru_lock-with-lruvec-lock-fix-2.patch
mm-lru-introduce-the-relock_page_lruvec-function-fix.patch
docs-vm-remove-unused-3-items-explanation-for-proc-vmstat.patch
mm-memcg-bail-early-from-swap-accounting-if-memcg-disabled.patch
mm-memcg-warning-on-memcg-after-readahead-page-charged.patch
