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SubjectRe: [PATCH 1/2] mm: use add_page_to_lru_list()/page_lru()/page_off_lru()
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在 2020/8/30 上午2:12, Yu Zhao 写道:
> On Thu, Aug 27, 2020 at 05:42:01PM -0600, Yu Zhao wrote:
>> This is a trivial but worth having clean-up patch. There should be
>> no side effects except page->lru is temporarily poisoned after it's
>> deleted but before it's added to the new list in move_pages_to_lru()
>> (which is not a problem).
>>
>> Signed-off-by: Yu Zhao <yuzhao@google.com>
>
> Hi Alex, I just realized your
> [v18,08/32] mm/vmscan: remove unnecessary lruvec adding
> at
> https://patchwork.kernel.org/patch/11733123/
> also touches move_pages_to_lru(). I agree it's better not to add
> a page we are going to free to the list in the first place. The
> rest in this patch would be too trivial to be a separate one (on
> top of yours).
>
> So would you mind taking of the clean-up too in your series? I'll
> drop this one then. Thanks.
>
>> ---
>> mm/swap.c | 4 +---
>> mm/vmscan.c | 14 ++++----------
>> 2 files changed, 5 insertions(+), 13 deletions(-)
>>
>> diff --git a/mm/swap.c b/mm/swap.c
>> index 40bf20a75278..2735ecf0f566 100644
>> --- a/mm/swap.c
>> +++ b/mm/swap.c
>> @@ -597,11 +597,9 @@ static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec,
>> {
>> if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) &&
>> !PageSwapCache(page) && !PageUnevictable(page)) {
>> - bool active = PageActive(page);
>> int nr_pages = thp_nr_pages(page);
>>
>> - del_page_from_lru_list(page, lruvec,
>> - LRU_INACTIVE_ANON + active);
>> + del_page_from_lru_list(page, lruvec, page_lru(page));
>> ClearPageActive(page);
>> ClearPageReferenced(page);
>> /*
>> diff --git a/mm/vmscan.c b/mm/vmscan.c
>> index 99e1796eb833..b479ced26cd3 100644
>> --- a/mm/vmscan.c
>> +++ b/mm/vmscan.c
>> @@ -1845,13 +1845,12 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
>> int nr_pages, nr_moved = 0;
>> LIST_HEAD(pages_to_free);
>> struct page *page;
>> - enum lru_list lru;
>>
>> while (!list_empty(list)) {
>> page = lru_to_page(list);
>> VM_BUG_ON_PAGE(PageLRU(page), page);
>> + list_del(&page->lru);
>> if (unlikely(!page_evictable(page))) {
>> - list_del(&page->lru);
>> spin_unlock_irq(&pgdat->lru_lock);
>> putback_lru_page(page);
>> spin_lock_irq(&pgdat->lru_lock);
>> @@ -1860,16 +1859,10 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
>> lruvec = mem_cgroup_page_lruvec(page, pgdat);
>>
>> SetPageLRU(page);
>> - lru = page_lru(page);
>> -
>> - nr_pages = thp_nr_pages(page);
>> - update_lru_size(lruvec, lru, page_zonenum(page), nr_pages);
>> - list_move(&page->lru, &lruvec->lists[lru]);
>> + add_page_to_lru_list(page, lruvec, page_lru(page));
>>
>> if (put_page_testzero(page)) {
>> - __ClearPageLRU(page);


it's interesting to know the PageLRU left has no bad impact in real life.
it justs seems a path confliction with my that patch.

>> - __ClearPageActive(page);
>> - del_page_from_lru_list(page, lruvec, lru);
>> + del_page_from_lru_list(page, lruvec, page_off_lru(page));
>>
>> if (unlikely(PageCompound(page))) {
>> spin_unlock_irq(&pgdat->lru_lock);
>> @@ -1878,6 +1871,7 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
>> } else
>> list_add(&page->lru, &pages_to_free);
>> } else {
>> + nr_pages = thp_nr_pages(page);
>> nr_moved += nr_pages;
>> if (PageActive(page))
>> workingset_age_nonresident(lruvec, nr_pages);
>> --
>> 2.28.0.402.g5ffc5be6b7-goog
>>

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