From: Alex Shi <alex.shi@linux.alibaba.com>
To: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, akpm@linux-foundation.org,
mgorman@techsingularity.net, tj@kernel.org, hughd@google.com,
daniel.m.jordan@oracle.com, yang.shi@linux.alibaba.com,
willy@infradead.org, shakeelb@google.com, hannes@cmpxchg.org
Cc: yun.wang@linux.alibaba.com
Subject: Re: [PATCH v7 01/10] mm/vmscan: remove unnecessary lruvec adding
Date: Mon, 13 Jan 2020 15:21:58 +0800 [thread overview]
Message-ID: <8f0f9fd5-56d3-0ec3-e875-f2eb5e1e7971@linux.alibaba.com> (raw)
In-Reply-To: <6c91fb0a-d4e0-d960-1cfd-62bef5cd15a5@yandex-team.ru>
在 2020/1/10 下午4:39, Konstantin Khlebnikov 写道:
> On 25/12/2019 12.04, Alex Shi wrote:
>> We don't have to add a freeable page into lru and then remove from it.
>> This change saves a couple of actions and makes the moving more clear.
>>
>> The SetPageLRU needs to be kept here for list intergrity. Otherwise:
>>
>> #0 mave_pages_to_lru #1 release_pages
>> if (put_page_testzero())
>> if (put_page_testzero())
>> !PageLRU //skip lru_lock
>> list_add(&page->lru,);
>> else
>> list_add(&page->lru,) //corrupt
>>
>> Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: Johannes Weiner <hannes@cmpxchg.org>
>> Cc: Hugh Dickins <hughd@google.com>
>> Cc: yun.wang@linux.alibaba.com
>> Cc: linux-mm@kvack.org
>> Cc: linux-kernel@vger.kernel.org
>> ---
>> mm/vmscan.c | 16 +++++++---------
>> 1 file changed, 7 insertions(+), 9 deletions(-)
>>
>> diff --git a/mm/vmscan.c b/mm/vmscan.c
>> index 572fb17c6273..8719361b47a0 100644
>> --- a/mm/vmscan.c
>> +++ b/mm/vmscan.c
>> @@ -1852,26 +1852,18 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
>
> Here is another cleanup: pass only pgdat as argument.
>
> This function reavaluates lruvec for each page under lru lock.
> Probably this is redundant for now but could be used in the future (or your patchset already use that).
Thanks a lot for comments, Konstantin!
yes, we could use pgdat here, but since to remove the pgdat later, maybe better to save this change? :)
>
>> 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);
>> continue;
>> }
>> - lruvec = mem_cgroup_page_lruvec(page, pgdat);
>> -
>
> Please leave a comment that we must set PageLRU before dropping our page reference.
Right, I will try to give a comments here.
>
>> SetPageLRU(page);
>> - lru = page_lru(page);
>> -
>> - nr_pages = hpage_nr_pages(page);
>> - update_lru_size(lruvec, lru, page_zonenum(page), nr_pages);
>> - list_move(&page->lru, &lruvec->lists[lru]);
>> if (put_page_testzero(page)) {
>> __ClearPageLRU(page);
>> __ClearPageActive(page);
>> - del_page_from_lru_list(page, lruvec, lru);
>> if (unlikely(PageCompound(page))) {
>> spin_unlock_irq(&pgdat->lru_lock);
>> @@ -1880,6 +1872,12 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
>> } else
>> list_add(&page->lru, &pages_to_free);
>> } else {
>> + lruvec = mem_cgroup_page_lruvec(page, pgdat);
>> + lru = page_lru(page);
>> + nr_pages = hpage_nr_pages(page);
>> +
>> + update_lru_size(lruvec, lru, page_zonenum(page), nr_pages);
>> + list_add(&page->lru, &lruvec->lists[lru]);
>> nr_moved += nr_pages;
>> }
>
> IMHO It looks better to in this way:>
> SetPageLRU()
>
> if (unlikely(put_page_testzero())) {
> <free>
> continue;
> }
>
> <add>
Yes, this looks better!
Thanks
Alex
>
>> }
>>
next prev parent reply other threads:[~2020-01-13 7:23 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-25 9:04 [PATCH v7 00/10] per lruvec lru_lock for memcg Alex Shi
2019-12-25 9:04 ` [PATCH v7 01/10] mm/vmscan: remove unnecessary lruvec adding Alex Shi
2020-01-10 8:39 ` Konstantin Khlebnikov
2020-01-13 7:21 ` Alex Shi [this message]
2019-12-25 9:04 ` [PATCH v7 02/10] mm/memcg: fold lru_lock in lock_page_lru Alex Shi
2020-01-10 8:49 ` Konstantin Khlebnikov
2020-01-13 9:45 ` Alex Shi
2020-01-13 9:55 ` Konstantin Khlebnikov
2020-01-13 12:47 ` Alex Shi
2020-01-13 16:34 ` Matthew Wilcox
2020-01-14 9:20 ` Alex Shi
2019-12-25 9:04 ` [PATCH v7 03/10] mm/lru: replace pgdat lru_lock with lruvec lock Alex Shi
2020-01-13 15:41 ` Daniel Jordan
2020-01-14 6:33 ` Alex Shi
2019-12-25 9:04 ` [PATCH v7 04/10] mm/lru: introduce the relock_page_lruvec function Alex Shi
2019-12-25 9:04 ` [PATCH v7 05/10] mm/mlock: optimize munlock_pagevec by relocking Alex Shi
2019-12-25 9:04 ` [PATCH v7 06/10] mm/swap: only change the lru_lock iff page's lruvec is different Alex Shi
2019-12-25 9:04 ` [PATCH v7 07/10] mm/pgdat: remove pgdat lru_lock Alex Shi
2019-12-25 9:04 ` [PATCH v7 08/10] mm/lru: revise the comments of lru_lock Alex Shi
2019-12-25 9:04 ` [PATCH v7 09/10] mm/lru: add debug checking for page memcg moving Alex Shi
2019-12-25 9:04 ` [PATCH v7 10/10] mm/memcg: add debug checking in lock_page_memcg Alex Shi
2019-12-31 23:05 ` [PATCH v7 00/10] per lruvec lru_lock for memcg Andrew Morton
2020-01-02 10:21 ` Alex Shi
2020-01-10 2:01 ` Alex Shi
2020-01-13 8:48 ` Hugh Dickins
2020-01-13 12:45 ` Alex Shi
2020-01-13 20:20 ` Hugh Dickins
2020-01-14 9:14 ` Alex Shi
2020-01-14 9:29 ` Alex Shi
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