From: Michal Hocko <mhocko@suse.com>
To: Yu Zhao <yuzhao@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Alex Shi <alex.shi@linux.alibaba.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Roman Gushchin <guro@fb.com>, Shakeel Butt <shakeelb@google.com>,
Chris Down <chris@chrisdown.name>,
Yafang Shao <laoar.shao@gmail.com>,
Vlastimil Babka <vbabka@suse.cz>,
Huang Ying <ying.huang@intel.com>,
Pankaj Gupta <pankaj.gupta.linux@gmail.com>,
Matthew Wilcox <willy@infradead.org>,
Konstantin Khlebnikov <koct9i@gmail.com>,
Minchan Kim <minchan@kernel.org>,
Jaewon Kim <jaewon31.kim@samsung.com>,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 01/13] mm: use add_page_to_lru_list()
Date: Fri, 18 Sep 2020 09:32:40 +0200 [thread overview]
Message-ID: <20200918073240.GD28827@dhcp22.suse.cz> (raw)
In-Reply-To: <20200918030051.650890-2-yuzhao@google.com>
On Thu 17-09-20 21:00:39, Yu Zhao wrote:
> This patch replaces the only open-coded lru list addition with
> add_page_to_lru_list().
>
> Before this patch, we have:
> update_lru_size()
> list_move()
>
> After this patch, we have:
> list_del()
> add_page_to_lru_list()
> update_lru_size()
> list_add()
>
> The only side effect is that page->lru is temporarily poisoned
> after a page is deleted from its old list, which shouldn't be a
> problem.
"because the lru lock is held" right?
Please always be explicit about your reasoning. "It shouldn't be a
problem" without further justification is just pointless for anybody
reading the code later on.
> Signed-off-by: Yu Zhao <yuzhao@google.com>
> ---
> mm/vmscan.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 9727dd8e2581..503fc5e1fe32 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -1850,8 +1850,8 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
> 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);
> @@ -1862,9 +1862,7 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
> 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, lru);
>
> if (put_page_testzero(page)) {
> __ClearPageLRU(page);
> @@ -1878,6 +1876,7 @@ 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);
> --
> 2.28.0.681.g6f77f65b4e-goog
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2020-09-18 7:32 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-18 3:00 [PATCH 00/13] mm: clean up some lru related pieces Yu Zhao
2020-09-18 3:00 ` [PATCH 01/13] mm: use add_page_to_lru_list() Yu Zhao
2020-09-18 7:32 ` Michal Hocko [this message]
2020-09-18 10:05 ` Yu Zhao
2020-09-18 3:00 ` [PATCH 02/13] mm: use page_off_lru() Yu Zhao
2020-09-18 7:37 ` Michal Hocko
2020-09-18 10:27 ` Yu Zhao
2020-09-18 11:09 ` Michal Hocko
2020-09-18 18:53 ` Yu Zhao
2020-09-21 11:16 ` Michal Hocko
2020-09-18 11:24 ` Michal Hocko
2020-09-18 3:00 ` [PATCH 03/13] mm: move __ClearPageLRU() into page_off_lru() Yu Zhao
2020-09-18 7:38 ` Michal Hocko
2020-09-18 3:00 ` [PATCH 04/13] mm: shuffle lru list addition and deletion functions Yu Zhao
2020-09-18 3:00 ` [PATCH 05/13] mm: don't pass enum lru_list to lru list addition functions Yu Zhao
2020-09-18 3:00 ` [PATCH 06/13] mm: don't pass enum lru_list to trace_mm_lru_insertion() Yu Zhao
2020-09-18 3:00 ` [PATCH 07/13] mm: don't pass enum lru_list to del_page_from_lru_list() Yu Zhao
2020-09-18 3:00 ` [PATCH 08/13] mm: rename page_off_lru() to __clear_page_lru_flags() Yu Zhao
2020-09-18 3:00 ` [PATCH 09/13] mm: inline page_lru_base_type() Yu Zhao
2020-09-18 3:00 ` [PATCH 10/13] mm: VM_BUG_ON lru page flags Yu Zhao
2020-09-18 3:00 ` [PATCH 11/13] mm: inline __update_lru_size() Yu Zhao
2020-09-18 3:00 ` [PATCH 12/13] mm: make lruvec_lru_size() static Yu Zhao
2020-09-18 3:00 ` [PATCH 13/13] mm: enlarge the int parameter of update_lru_size() Yu Zhao
2020-09-18 7:45 ` [PATCH 00/13] mm: clean up some lru related pieces Michal Hocko
2020-09-18 9:36 ` Yu Zhao
2020-09-18 20:46 ` Hugh Dickins
2020-09-18 21:01 ` Yu Zhao
2020-09-18 21:19 ` Hugh Dickins
2020-09-19 0:31 ` Alex Shi
2020-10-13 2:30 ` Hugh Dickins
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