From: Alex Shi <alex.shi@linux.alibaba.com>
To: unlisted-recipients:; (no To-header on input)
Cc: Konstantin Khlebnikov <koct9i@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>, Yu Zhao <yuzhao@google.com>,
Michal Hocko <mhocko@suse.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH next] mm/swap.c: reduce lock contention in lru_cache_add
Date: Fri, 20 Nov 2020 16:27:27 +0800 [thread overview]
Message-ID: <1605860847-47445-1-git-send-email-alex.shi@linux.alibaba.com> (raw)
The current relock logical will change lru_lock when found a new
lruvec, so if 2 memcgs are reading file or alloc page at same time,
they could hold the lru_lock alternately, and wait for each other for
fairness attribute of ticket spin lock.
This patch will sort that all lru_locks and only hold them once in
above scenario. That could reduce fairness waiting for lock reget.
Than, vm-scalability/case-lru-file-readtwice could get ~5% performance
gain on my 2P*20core*HT machine.
Suggested-by: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
mm/swap.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++--------
1 file changed, 49 insertions(+), 8 deletions(-)
diff --git a/mm/swap.c b/mm/swap.c
index 490553f3f9ef..c787b38bf9c0 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -1009,24 +1009,65 @@ static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec)
trace_mm_lru_insertion(page, lru);
}
+struct lruvecs {
+ struct list_head lists[PAGEVEC_SIZE];
+ struct lruvec *vecs[PAGEVEC_SIZE];
+};
+
+/* Sort pvec pages on their lruvec */
+int sort_page_lruvec(struct lruvecs *lruvecs, struct pagevec *pvec)
+{
+ int i, j, nr_lruvec;
+ struct page *page;
+ struct lruvec *lruvec = NULL;
+
+ lruvecs->vecs[0] = NULL;
+ for (i = nr_lruvec = 0; i < pagevec_count(pvec); i++) {
+ page = pvec->pages[i];
+ lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
+
+ /* Try to find a same lruvec */
+ for (j = 0; j <= nr_lruvec; j++)
+ if (lruvec == lruvecs->vecs[j])
+ break;
+
+ /* A new lruvec */
+ if (j > nr_lruvec) {
+ INIT_LIST_HEAD(&lruvecs->lists[nr_lruvec]);
+ lruvecs->vecs[nr_lruvec] = lruvec;
+ j = nr_lruvec++;
+ lruvecs->vecs[nr_lruvec] = 0;
+ }
+
+ list_add_tail(&page->lru, &lruvecs->lists[j]);
+ }
+
+ return nr_lruvec;
+}
+
/*
* Add the passed pages to the LRU, then drop the caller's refcount
* on them. Reinitialises the caller's pagevec.
*/
void __pagevec_lru_add(struct pagevec *pvec)
{
- int i;
- struct lruvec *lruvec = NULL;
+ int i, nr_lruvec;
unsigned long flags = 0;
+ struct page *page;
+ struct lruvecs lruvecs;
- for (i = 0; i < pagevec_count(pvec); i++) {
- struct page *page = pvec->pages[i];
+ nr_lruvec = sort_page_lruvec(&lruvecs, pvec);
- lruvec = relock_page_lruvec_irqsave(page, lruvec, &flags);
- __pagevec_lru_add_fn(page, lruvec);
+ for (i = 0; i < nr_lruvec; i++) {
+ spin_lock_irqsave(&lruvecs.vecs[i]->lru_lock, flags);
+ while (!list_empty(&lruvecs.lists[i])) {
+ page = lru_to_page(&lruvecs.lists[i]);
+ list_del(&page->lru);
+ __pagevec_lru_add_fn(page, lruvecs.vecs[i]);
+ }
+ spin_unlock_irqrestore(&lruvecs.vecs[i]->lru_lock, flags);
}
- if (lruvec)
- unlock_page_lruvec_irqrestore(lruvec, flags);
+
release_pages(pvec->pages, pvec->nr);
pagevec_reinit(pvec);
}
--
2.29.GIT
next reply other threads:[~2020-11-20 8:27 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-20 8:27 Alex Shi [this message]
2020-11-20 23:19 ` [PATCH next] mm/swap.c: reduce lock contention in lru_cache_add Andrew Morton
2020-11-23 4:46 ` Alex Shi
2020-11-25 15:38 ` Vlastimil Babka
2020-11-26 3:12 ` Alex Shi
2020-11-26 11:05 ` Vlastimil Babka
2020-11-26 4:52 ` Yu Zhao
2020-11-26 6:39 ` Alex Shi
2020-11-26 7:24 ` Yu Zhao
2020-11-26 8:09 ` Alex Shi
2020-11-26 11:22 ` Vlastimil Babka
2020-11-26 15:44 ` Vlastimil Babka
2020-11-26 15:55 ` Matthew Wilcox
2020-11-27 3:14 ` Alex Shi
2020-12-01 8:02 ` [PATCH 1/3] mm/swap.c: pre-sort pages in pagevec for pagevec_lru_move_fn Alex Shi
2020-12-01 8:02 ` [PATCH 2/3] mm/swap.c: bail out early for no memcg and no numa Alex Shi
2020-12-01 8:02 ` [PATCH 3/3] mm/swap.c: extend the usage to pagevec_lru_add Alex Shi
2020-12-01 8:10 ` [PATCH 1/3] mm/swap.c: pre-sort pages in pagevec for pagevec_lru_move_fn Michal Hocko
2020-12-01 8:20 ` Alex Shi
2020-12-25 9:59 ` [RFC PATCH 0/4] pre sort pages on lruvec in pagevec Alex Shi
2020-12-25 9:59 ` [RFC PATCH 1/4] mm/swap.c: pre-sort pages in pagevec for pagevec_lru_move_fn Alex Shi
2020-12-25 9:59 ` [RFC PATCH 2/4] mm/swap.c: bail out early for no memcg and no numa Alex Shi
2020-12-25 9:59 ` [RFC PATCH 3/4] mm/swap.c: extend the usage to pagevec_lru_add Alex Shi
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1605860847-47445-1-git-send-email-alex.shi@linux.alibaba.com \
--to=alex.shi@linux.alibaba.com \
--cc=akpm@linux-foundation.org \
--cc=hughd@google.com \
--cc=koct9i@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@suse.com \
--cc=yuzhao@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).