On Sun, Aug 30, 2020 at 04:31:38PM +0800, Alex Shi wrote: > > > 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@xxxxxxxxxx> > > > > 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. Ok, maybe I wasn't clear before. Please see what exactly I'm asking you to consider below. > >> 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); > >> /* 1) The above has no conflict with your series and therefore can go separately. Feel free to include it. > >> 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); 2) The above is the same change you've made. > >> @@ -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. (No, we can't leave PG_lru uncleared. It's done by the page_off_lru() right below). > >> - __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); 3) The above is the conflict. Since we won't add and then delete a page after your patch, we won't need it. But I do want this (you've snipped from your reply, so I take that you already figured it out): - 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)); No worries if you prefer this to go separately too.
