From: Alex Shi <alex.shi@linux.alibaba.com>
To: Alexander Duyck <alexander.duyck@gmail.com>
Cc: "Duyck, Alexander H" <alexander.h.duyck@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
cgroups@vger.kernel.org,
Daniel Jordan <daniel.m.jordan@oracle.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Hugh Dickins <hughd@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>, kbuild test robot <lkp@intel.com>,
Mel Gorman <mgorman@techsingularity.net>,
Wei Yang <richard.weiyang@gmail.com>,
Rong Chen <rong.a.chen@intel.com>,
Shakeel Butt <shakeelb@google.com>,
Thomas Gleixner <tglx@linutronix.de>, Tejun Heo <tj@kernel.org>,
Matthew Wilcox <willy@infradead.org>,
Yang Shi <yang.shi@linux.alibaba.com>
Subject: Re: [PATCH RFC] mm: Add function for testing if the current lruvec lock is valid
Date: Tue, 4 Aug 2020 14:13:43 +0800 [thread overview]
Message-ID: <c5130b1b-cc60-d518-75d6-7a182fe9d343@linux.alibaba.com> (raw)
In-Reply-To: <CAKgT0UcDbzb_MXynzZANvJ_bV4VEguhxgOt2-hp4cNtvwE-r_Q@mail.gmail.com>
在 2020/8/3 上午2:20, Alexander Duyck 写道:
> Feel free to fold it into your patches if you want.
>
> I think Hugh was the one that had submitted a patch that addressed it,
> and it looks like you folded that into your v17 set. It was probably
> what he had identified which was the additional LRU checks needing to
> be removed from the code.
Yes, Hugh's patch was folded into patch [PATCH v17 16/21] mm/swap: serialize memcg changes in pagevec_lru_move_fn
and your change is on patch 18. seems there are no interfere with each other.
Both of patches are fine.
Thanks
>
> Thanks.
>
> - Alex
>
> On Fri, Jul 31, 2020 at 4:55 PM Alex Shi <alex.shi@linux.alibaba.com> wrote:
>>
>> It looks much better than mine. and could replace 'mm/lru: introduce the relock_page_lruvec function'
>> with your author signed. :)
>>
>> BTW,
>> it's the rcu_read_lock cause the will-it-scale/page_fault3 regression which you mentained in another
>> letter?
>>
>> Thanks
>> Alex
>>
>> 在 2020/8/1 上午5:14, alexander.h.duyck@intel.com 写道:
>>> From: Alexander Duyck <alexander.h.duyck@linux.intel.com>
>>>
>>> When testing for relock we can avoid the need for RCU locking if we simply
>>> compare the page pgdat and memcg pointers versus those that the lruvec is
>>> holding. By doing this we can avoid the extra pointer walks and accesses of
>>> the memory cgroup.
>>>
>>> In addition we can avoid the checks entirely if lruvec is currently NULL.
>>>
>>> Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
>>> ---
>>> include/linux/memcontrol.h | 52 +++++++++++++++++++++++++++-----------------
>>> 1 file changed, 32 insertions(+), 20 deletions(-)
>>>
>>> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
>>> index 6e670f991b42..7a02f00bf3de 100644
>>> --- a/include/linux/memcontrol.h
>>> +++ b/include/linux/memcontrol.h
>>> @@ -405,6 +405,22 @@ static inline struct lruvec *mem_cgroup_lruvec(struct mem_cgroup *memcg,
>>>
>>> struct lruvec *mem_cgroup_page_lruvec(struct page *, struct pglist_data *);
>>>
>>> +static inline bool lruvec_holds_page_lru_lock(struct page *page,
>>> + struct lruvec *lruvec)
>>> +{
>>> + pg_data_t *pgdat = page_pgdat(page);
>>> + const struct mem_cgroup *memcg;
>>> + struct mem_cgroup_per_node *mz;
>>> +
>>> + if (mem_cgroup_disabled())
>>> + return lruvec == &pgdat->__lruvec;
>>> +
>>> + mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
>>> + memcg = page->mem_cgroup ? : root_mem_cgroup;
>>> +
>>> + return lruvec->pgdat == pgdat && mz->memcg == memcg;
>>> +}
>>> +
>>> struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
>>>
>>> struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm);
>>> @@ -880,6 +896,14 @@ static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
>>> return &pgdat->__lruvec;
>>> }
>>>
>>> +static inline bool lruvec_holds_page_lru_lock(struct page *page,
>>> + struct lruvec *lruvec)
>>> +{
>>> + pg_data_t *pgdat = page_pgdat(page);
>>> +
>>> + return lruvec == &pgdat->__lruvec;
>>> +}
>>> +
>>> static inline struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
>>> {
>>> return NULL;
>>> @@ -1317,18 +1341,12 @@ static inline void unlock_page_lruvec_irqrestore(struct lruvec *lruvec,
>>> static inline struct lruvec *relock_page_lruvec_irq(struct page *page,
>>> struct lruvec *locked_lruvec)
>>> {
>>> - struct pglist_data *pgdat = page_pgdat(page);
>>> - bool locked;
>>> + if (locked_lruvec) {
>>> + if (lruvec_holds_page_lru_lock(page, locked_lruvec))
>>> + return locked_lruvec;
>>>
>>> - rcu_read_lock();
>>> - locked = mem_cgroup_page_lruvec(page, pgdat) == locked_lruvec;
>>> - rcu_read_unlock();
>>> -
>>> - if (locked)
>>> - return locked_lruvec;
>>> -
>>> - if (locked_lruvec)
>>> unlock_page_lruvec_irq(locked_lruvec);
>>> + }
>>>
>>> return lock_page_lruvec_irq(page);
>>> }
>>> @@ -1337,18 +1355,12 @@ static inline struct lruvec *relock_page_lruvec_irq(struct page *page,
>>> static inline struct lruvec *relock_page_lruvec_irqsave(struct page *page,
>>> struct lruvec *locked_lruvec, unsigned long *flags)
>>> {
>>> - struct pglist_data *pgdat = page_pgdat(page);
>>> - bool locked;
>>> -
>>> - rcu_read_lock();
>>> - locked = mem_cgroup_page_lruvec(page, pgdat) == locked_lruvec;
>>> - rcu_read_unlock();
>>> -
>>> - if (locked)
>>> - return locked_lruvec;
>>> + if (locked_lruvec) {
>>> + if (lruvec_holds_page_lru_lock(page, locked_lruvec))
>>> + return locked_lruvec;
>>>
>>> - if (locked_lruvec)
>>> unlock_page_lruvec_irqrestore(locked_lruvec, *flags);
>>> + }
>>>
>>> return lock_page_lruvec_irqsave(page, flags);
>>> }
>>>
>>
next prev parent reply other threads:[~2020-08-04 6:14 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-25 12:59 [PATCH v17 00/21] per memcg lru lock Alex Shi
2020-07-25 12:59 ` [PATCH v17 01/21] mm/vmscan: remove unnecessary lruvec adding Alex Shi
2020-08-06 3:47 ` Alex Shi
2020-07-25 12:59 ` [PATCH v17 02/21] mm/page_idle: no unlikely double check for idle page counting Alex Shi
2020-07-25 12:59 ` [PATCH v17 03/21] mm/compaction: correct the comments of compact_defer_shift Alex Shi
2020-07-27 17:29 ` Alexander Duyck
2020-07-28 11:59 ` Alex Shi
2020-07-28 14:17 ` Alexander Duyck
2020-07-25 12:59 ` [PATCH v17 04/21] mm/compaction: rename compact_deferred as compact_should_defer Alex Shi
2020-07-25 12:59 ` [PATCH v17 05/21] mm/thp: move lru_add_page_tail func to huge_memory.c Alex Shi
2020-07-25 12:59 ` [PATCH v17 06/21] mm/thp: clean up lru_add_page_tail Alex Shi
2020-07-25 12:59 ` [PATCH v17 07/21] mm/thp: remove code path which never got into Alex Shi
2020-07-25 12:59 ` [PATCH v17 08/21] mm/thp: narrow lru locking Alex Shi
2020-07-25 12:59 ` [PATCH v17 09/21] mm/memcg: add debug checking in lock_page_memcg Alex Shi
2020-07-25 12:59 ` [PATCH v17 10/21] mm/swap: fold vm event PGROTATED into pagevec_move_tail_fn Alex Shi
2020-07-25 12:59 ` [PATCH v17 11/21] mm/lru: move lru_lock holding in func lru_note_cost_page Alex Shi
2020-08-05 21:18 ` Alexander Duyck
2020-07-25 12:59 ` [PATCH v17 12/21] mm/lru: move lock into lru_note_cost Alex Shi
2020-07-25 12:59 ` [PATCH v17 13/21] mm/lru: introduce TestClearPageLRU Alex Shi
2020-07-29 3:53 ` Alex Shi
2020-08-05 22:43 ` Alexander Duyck
2020-08-06 1:54 ` Alex Shi
2020-08-06 14:41 ` Alexander Duyck
2020-07-25 12:59 ` [PATCH v17 14/21] mm/compaction: do page isolation first in compaction Alex Shi
2020-08-04 21:35 ` Alexander Duyck
2020-08-06 18:38 ` Alexander Duyck
2020-08-07 3:24 ` Alex Shi
2020-08-07 14:51 ` Alexander Duyck
2020-08-10 13:10 ` Alex Shi
2020-08-10 14:41 ` Alexander Duyck
2020-08-11 8:22 ` Alex Shi
2020-08-11 14:47 ` Alexander Duyck
2020-08-12 11:43 ` Alex Shi
2020-08-12 12:16 ` Alex Shi
2020-08-12 16:51 ` Alexander Duyck
2020-08-13 1:46 ` Alex Shi
2020-08-13 2:17 ` Alexander Duyck
2020-08-13 3:52 ` Alex Shi
2020-08-13 4:02 ` [RFC PATCH 0/3] " Alexander Duyck
2020-08-13 4:02 ` [RFC PATCH 1/3] mm: Drop locked from isolate_migratepages_block Alexander Duyck
2020-08-13 6:56 ` Alex Shi
2020-08-13 14:32 ` Alexander Duyck
2020-08-14 7:25 ` Alex Shi
2020-08-13 7:44 ` Alex Shi
2020-08-13 14:26 ` Alexander Duyck
2020-08-13 4:02 ` [RFC PATCH 2/3] mm: Drop use of test_and_set_skip in favor of just setting skip Alexander Duyck
2020-08-14 7:19 ` Alex Shi
2020-08-14 14:24 ` Alexander Duyck
2020-08-14 21:15 ` Alexander Duyck
2020-08-15 9:49 ` Alex Shi
2020-08-17 15:38 ` Alexander Duyck
2020-08-18 6:50 ` Alex Shi
2020-08-13 4:02 ` [RFC PATCH 3/3] mm: Identify compound pages sooner in isolate_migratepages_block Alexander Duyck
2020-08-14 7:20 ` Alex Shi
2020-08-17 22:58 ` [PATCH v17 14/21] mm/compaction: do page isolation first in compaction Alexander Duyck
2020-07-25 12:59 ` [PATCH v17 15/21] mm/thp: add tail pages into lru anyway in split_huge_page() Alex Shi
2020-07-25 12:59 ` [PATCH v17 16/21] mm/swap: serialize memcg changes in pagevec_lru_move_fn Alex Shi
2020-07-25 12:59 ` [PATCH v17 17/21] mm/lru: replace pgdat lru_lock with lruvec lock Alex Shi
2020-07-27 23:34 ` Alexander Duyck
2020-07-28 7:15 ` Alex Shi
2020-07-28 11:19 ` Alex Shi
2020-07-28 14:54 ` Alexander Duyck
2020-07-29 1:00 ` Alex Shi
2020-07-29 1:27 ` Alexander Duyck
2020-07-29 2:27 ` Alex Shi
2020-07-28 15:39 ` Alex Shi
2020-07-28 15:55 ` Alexander Duyck
2020-07-29 0:48 ` Alex Shi
2020-07-29 3:54 ` Alex Shi
2020-08-06 7:41 ` Alex Shi
2020-07-25 12:59 ` [PATCH v17 18/21] mm/lru: introduce the relock_page_lruvec function Alex Shi
2020-07-29 17:52 ` Alexander Duyck
2020-07-30 6:08 ` Alex Shi
2020-07-31 14:20 ` Alexander Duyck
2020-07-31 21:14 ` [PATCH RFC] mm: Add function for testing if the current lruvec lock is valid alexander.h.duyck
2020-07-31 23:54 ` Alex Shi
2020-08-02 18:20 ` Alexander Duyck
2020-08-04 6:13 ` Alex Shi [this message]
2020-07-25 12:59 ` [PATCH v17 19/21] mm/vmscan: use relock for move_pages_to_lru Alex Shi
2020-08-03 22:49 ` Alexander Duyck
2020-08-04 6:23 ` Alex Shi
2020-07-25 12:59 ` [PATCH v17 20/21] mm/pgdat: remove pgdat lru_lock Alex Shi
2020-08-03 22:42 ` Alexander Duyck
2020-08-03 22:45 ` Alexander Duyck
2020-08-04 6:22 ` Alex Shi
2020-07-25 12:59 ` [PATCH v17 21/21] mm/lru: revise the comments of lru_lock Alex Shi
2020-08-03 22:37 ` Alexander Duyck
2020-08-04 10:04 ` Alex Shi
2020-08-04 14:29 ` Alexander Duyck
2020-08-06 1:39 ` Alex Shi
2020-08-06 16:27 ` Alexander Duyck
2020-07-27 5:40 ` [PATCH v17 00/21] per memcg lru lock Alex Shi
2020-07-29 14:49 ` Alex Shi
2020-07-29 18:06 ` Hugh Dickins
2020-07-30 2:16 ` Alex Shi
2020-08-03 15:07 ` Michal Hocko
2020-08-04 6:14 ` Alex Shi
2020-07-31 21:31 ` Alexander Duyck
2020-08-04 8:36 ` Alex Shi
2020-08-04 8:36 ` Alex Shi
2020-08-04 8:37 ` Alex Shi
2020-08-04 8:37 ` Alex Shi
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