From: "解 咏梅" <yongmeixie@hotmail.com>
To: "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: 回复: [PATCH] mm:vmscan: fix extra adjustment for lruvec's nonresident_age in case of reactivation
Date: Mon, 20 Sep 2021 03:11:02 +0000 [thread overview]
Message-ID: <TYYP286MB11150F9D24DF4DEFF5D89F8DC5A09@TYYP286MB1115.JPNP286.PROD.OUTLOOK.COM> (raw)
In-Reply-To: <TYCP286MB1108D012DA436CA72029ACA7C5DF9@TYCP286MB1108.JPNP286.PROD.OUTLOOK.COM>
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Sorry, list_move can cause some problem when deleting a entry not on list any more (AKA DEBUG_LIST in enabled)
I corrected the patch as the attached.
Best Regards,
Yongmei.
________________________________
发件人: Yongmei Xie <yongmeixie@hotmail.com>
发送时间: 2021年9月19日 23:25
收件人: akpm@linux-foundation.org <akpm@linux-foundation.org>; linux-mm@kvack.org <linux-mm@kvack.org>; linux-kernel@vger.kernel.org <linux-kernel@vger.kernel.org>
抄送: yongmeixie@hotmail.com <yongmeixie@hotmail.com>
主题: [PATCH] mm:vmscan: fix extra adjustment for lruvec's nonresident_age in case of reactivation
Before commit #31d8fcac, VM didn't increase nonresident_age (AKA inactive age for
file pages) in shrink_page_list. When putback_inactive_pages was converged with
move_pages_to_lru, both shrink_active_list and shrink_page_list use the same
function to handle move pages to the appropriate lru under lru lock's protection.
At those day, VM didn't increase nonresident_age for second chance promotion.
Commit #31d8fcac fix the problem. Definitely, we should account the activation
for second chance. But move_pages_to_lru is used in reactivation in active lru
as well for protecting code section. So I suggest to add another variable to
tell whether reactivation or not.
Signed-off-by: Yongmei Xie <yongmeixie@hotmail.com>
---
mm/vmscan.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 74296c2d1fed..85ccafcd4912 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2152,7 +2152,8 @@ static int too_many_isolated(struct pglist_data *pgdat, int file,
* Returns the number of pages moved to the given lruvec.
*/
static unsigned int move_pages_to_lru(struct lruvec *lruvec,
- struct list_head *list)
+ struct list_head *list,
+ bool reactivation)
{
int nr_pages, nr_moved = 0;
LIST_HEAD(pages_to_free);
@@ -2203,7 +2204,7 @@ static unsigned int move_pages_to_lru(struct lruvec *lruvec,
add_page_to_lru_list(page, lruvec);
nr_pages = thp_nr_pages(page);
nr_moved += nr_pages;
- if (PageActive(page))
+ if (PageActive(page) && !reactivation)
workingset_age_nonresident(lruvec, nr_pages);
}
@@ -2281,7 +2282,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
nr_reclaimed = shrink_page_list(&page_list, pgdat, sc, &stat, false);
spin_lock_irq(&lruvec->lru_lock);
- move_pages_to_lru(lruvec, &page_list);
+ move_pages_to_lru(lruvec, &page_list, false);
__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT;
@@ -2418,8 +2419,8 @@ static void shrink_active_list(unsigned long nr_to_scan,
*/
spin_lock_irq(&lruvec->lru_lock);
- nr_activate = move_pages_to_lru(lruvec, &l_active);
- nr_deactivate = move_pages_to_lru(lruvec, &l_inactive);
+ nr_activate = move_pages_to_lru(lruvec, &l_active, true);
+ nr_deactivate = move_pages_to_lru(lruvec, &l_inactive, false);
/* Keep all free pages in l_active list */
list_splice(&l_inactive, &l_active);
--
2.18.2
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From d25dea3adb696454cc926b644566e055008d752a Mon Sep 17 00:00:00 2001
From: Yongmei Xie <yongmeixie@hotmail.com>
Date: Sun, 19 Sep 2021 22:57:50 +0800
Subject: [PATCH v2] mm:vmscan remove unnecessary lru lock unlock/lock pair
There's code redundant in move_pages_to_lru. When there're multiple of mlocked pages
or compound pages, the original implementation tries to unlock and then lock to handle
some exceptional case.
Signed-off-by: Yongmei Xie <yongmeixie@hotmail.com>
---
mm/vmscan.c | 32 ++++++++++++++++++++++++--------
1 file changed, 24 insertions(+), 8 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 74296c2d1fed..045ca34272c1 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2156,6 +2156,8 @@ static unsigned int move_pages_to_lru(struct lruvec *lruvec,
{
int nr_pages, nr_moved = 0;
LIST_HEAD(pages_to_free);
+ LIST_HEAD(pages_to_putback);
+ LIST_HEAD(compound_pages_to_free);
struct page *page;
while (!list_empty(list)) {
@@ -2163,9 +2165,7 @@ static unsigned int move_pages_to_lru(struct lruvec *lruvec,
VM_BUG_ON_PAGE(PageLRU(page), page);
list_del(&page->lru);
if (unlikely(!page_evictable(page))) {
- spin_unlock_irq(&lruvec->lru_lock);
- putback_lru_page(page);
- spin_lock_irq(&lruvec->lru_lock);
+ list_add(&page->lru, &pages_to_putback);
continue;
}
@@ -2185,11 +2185,9 @@ static unsigned int move_pages_to_lru(struct lruvec *lruvec,
if (unlikely(put_page_testzero(page))) {
__clear_page_lru_flags(page);
- if (unlikely(PageCompound(page))) {
- spin_unlock_irq(&lruvec->lru_lock);
- destroy_compound_page(page);
- spin_lock_irq(&lruvec->lru_lock);
- } else
+ if (unlikely(PageCompound(page)))
+ list_add(&page->lru, &compound_pages_to_free);
+ else
list_add(&page->lru, &pages_to_free);
continue;
@@ -2207,6 +2205,24 @@ static unsigned int move_pages_to_lru(struct lruvec *lruvec,
workingset_age_nonresident(lruvec, nr_pages);
}
+ spin_unlock_irq(&lruvec->lru_lock);
+ /*
+ * Putback as a batch to reduce unlock/lock pair for unevictable pages
+ */
+ while (!list_empty(&pages_to_putback)) {
+ page = lru_to_page(&pages_to_putback);
+ putback_lru_page(page);
+ }
+
+ /*
+ * Free compound page as a batch to reduce unnecessary unlock/lock
+ */
+ while (!list_empty(&compound_pages_to_free)) {
+ page = lru_to_page(&compound_pages_to_free);
+ destroy_compound_page(page);
+ }
+ spin_lock_irq(&lruvec->lru_lock);
+
/*
* To save our caller's stack, now use input list for pages to free.
*/
--
2.18.2
next prev parent reply other threads:[~2021-09-20 3:11 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-19 15:25 [PATCH] mm:vmscan: fix extra adjustment for lruvec's nonresident_age in case of reactivation Yongmei Xie
2021-09-20 3:11 ` 解 咏梅 [this message]
2021-09-21 14:48 ` Johannes Weiner
[not found] ` <TYYP286MB11150330E283CC23CB16E40CC5A29@TYYP286MB1115.JPNP286.PROD.OUTLOOK.COM>
2021-10-01 16:43 ` 回复: " Johannes Weiner
[not found] ` <TYYP286MB1115E3D67A88FFF1BFB68996C5B19@TYYP286MB1115.JPNP286.PROD.OUTLOOK.COM>
2021-10-07 16:34 ` 回复: " Johannes Weiner
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