From: Yu Zhao <yuzhao@google.com>
To: akpm@linux-foundation.org, vbabka@suse.cz
Cc: alex.shi@linux.alibaba.com, guro@fb.com, hannes@cmpxchg.org,
hughd@google.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, mhocko@kernel.org, vdavydov.dev@gmail.com,
willy@infradead.org, Yu Zhao <yuzhao@google.com>
Subject: [PATCH] mm: test page->flags directly in page_lru()
Date: Wed, 24 Feb 2021 01:48:07 -0700 [thread overview]
Message-ID: <20210224084807.2179942-1-yuzhao@google.com> (raw)
In-Reply-To: <20210122220600.906146-11-yuzhao@google.com>
Currently page_lru() uses Page{Active,Unevictable} to determine which
lru list a page belongs to. Page{Active,Unevictable} contain
compound_head() and therefore page_lru() essentially tests
PG_{active,unevictable} against compound_head(page)->flags. Once an
lru list is determined, page->lru, rather than
compound_head(page)->lru, will be added to or deleted from it.
Though not bug, having compound_head() in page_lru() increases the
size of vmlinux by O(KB) because page_lru() is inlined many places.
And removing compound_head() entirely from Page{Active,Unevictable}
may not be the best option (for the moment) either because there
may be other cases that need compound_head(). This patch makes
page_lru() and __clear_page_lru_flags(), which are used immediately
before and after operations on page->lru, test
PG_{active,unevictable} directly against page->flags instead.
scripts/bloat-o-meter results before and after the entire series:
Glang: add/remove: 0/1 grow/shrink: 7/10 up/down: 191/-1189 (-998)
GCC: add/remove: 0/1 grow/shrink: 9/9 up/down: 1010/-783 (227)
Signed-off-by: Yu Zhao <yuzhao@google.com>
---
include/linux/mm_inline.h | 21 +++++++--------------
1 file changed, 7 insertions(+), 14 deletions(-)
diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index 355ea1ee32bd..1b8df9e6f63f 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -46,14 +46,12 @@ static __always_inline void __clear_page_lru_flags(struct page *page)
{
VM_BUG_ON_PAGE(!PageLRU(page), page);
- __ClearPageLRU(page);
-
/* this shouldn't happen, so leave the flags to bad_page() */
- if (PageActive(page) && PageUnevictable(page))
+ if ((page->flags & (BIT(PG_active) | BIT(PG_unevictable))) ==
+ (BIT(PG_active) | BIT(PG_unevictable)))
return;
- __ClearPageActive(page);
- __ClearPageUnevictable(page);
+ page->flags &= ~(BIT(PG_lru) | BIT(PG_active) | BIT(PG_unevictable));
}
/**
@@ -65,18 +63,13 @@ static __always_inline void __clear_page_lru_flags(struct page *page)
*/
static __always_inline enum lru_list page_lru(struct page *page)
{
- enum lru_list lru;
+ unsigned long flags = READ_ONCE(page->flags);
VM_BUG_ON_PAGE(PageActive(page) && PageUnevictable(page), page);
- if (PageUnevictable(page))
- return LRU_UNEVICTABLE;
-
- lru = page_is_file_lru(page) ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON;
- if (PageActive(page))
- lru += LRU_ACTIVE;
-
- return lru;
+ /* test page->flags directly to avoid unnecessary compound_head() */
+ return (flags & BIT(PG_unevictable)) ? LRU_UNEVICTABLE :
+ (LRU_FILE * !(flags & BIT(PG_swapbacked)) + !!(flags & BIT(PG_active)));
}
static __always_inline void add_page_to_lru_list(struct page *page,
--
2.30.0.617.g56c4b15f3c-goog
next prev parent reply other threads:[~2021-02-24 8:49 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-22 22:05 [PATCH v2 00/10] mm: lru related cleanups Yu Zhao
2021-01-22 22:05 ` [PATCH v2 01/10] mm: use add_page_to_lru_list() Yu Zhao
2021-01-26 18:57 ` Vlastimil Babka
2021-01-27 2:12 ` Miaohe Lin
2021-01-22 22:05 ` [PATCH v2 02/10] mm: shuffle lru list addition and deletion functions Yu Zhao
2021-01-26 18:58 ` Vlastimil Babka
2021-01-27 2:14 ` Miaohe Lin
2021-01-22 22:05 ` [PATCH v2 03/10] mm: don't pass "enum lru_list" to lru list addition functions Yu Zhao
2021-01-26 19:13 ` Vlastimil Babka
2021-01-26 21:34 ` Yu Zhao
2021-01-27 10:51 ` Vlastimil Babka
2021-01-26 22:01 ` Matthew Wilcox
2021-01-26 22:14 ` Yu Zhao
2021-02-23 22:50 ` Andrew Morton
2021-02-24 5:29 ` Yu Zhao
2021-02-24 8:06 ` Alex Shi
2021-02-24 8:37 ` Yu Zhao
2021-02-24 9:01 ` Alex Shi
2021-01-22 22:05 ` [PATCH v2 04/10] mm: don't pass "enum lru_list" to trace_mm_lru_insertion() Yu Zhao
2021-01-22 22:05 ` [PATCH v2 05/10] mm: don't pass "enum lru_list" to del_page_from_lru_list() Yu Zhao
2021-01-22 22:05 ` [PATCH v2 06/10] mm: add __clear_page_lru_flags() to replace page_off_lru() Yu Zhao
2021-01-22 22:05 ` [PATCH v2 07/10] mm: VM_BUG_ON lru page flags Yu Zhao
2021-01-22 22:05 ` [PATCH v2 08/10] mm: fold page_lru_base_type() into its sole caller Yu Zhao
2021-01-22 22:05 ` [PATCH v2 09/10] mm: fold __update_lru_size() " Yu Zhao
2021-01-22 22:06 ` [PATCH v2 10/10] mm: make lruvec_lru_size() static Yu Zhao
2021-02-24 8:48 ` Yu Zhao [this message]
2021-02-24 13:15 ` [PATCH] mm: test page->flags directly in page_lru() Andrew Morton
2021-02-24 19:57 ` Yu Zhao
2021-02-24 21:56 ` Matthew Wilcox
2021-02-24 22:34 ` Yu Zhao
2021-02-24 22:48 ` Matthew Wilcox
2021-02-24 23:50 ` Yu Zhao
2021-02-25 3:55 ` Matthew Wilcox
2021-02-25 5:22 ` Yu Zhao
2021-02-25 12:12 ` Matthew Wilcox
2021-02-26 9:17 ` [PATCH v2 0/3] trim the uses of compound_head() Yu Zhao
2021-02-26 9:17 ` [PATCH v2 1/3] mm: bypass compound_head() for PF_NO_TAIL when enforce=1 Yu Zhao
2021-02-26 9:17 ` [PATCH v2 2/3] mm: use PF_NO_TAIL for PG_lru Yu Zhao
2021-02-26 20:22 ` Yu Zhao
2021-02-26 9:17 ` [PATCH v2 3/3] mm: use PF_ONLY_HEAD for PG_active and PG_unevictable Yu Zhao
2021-02-26 12:13 ` Matthew Wilcox
2021-02-26 19:49 ` Yu Zhao
2021-02-26 20:27 ` Matthew Wilcox
2021-03-01 11:50 ` Kirill A. Shutemov
2021-03-01 19:58 ` Yu Zhao
2021-03-01 20:16 ` Hugh Dickins
2021-03-01 20:26 ` Matthew Wilcox
2021-02-26 10:52 ` [PATCH v2 0/3] trim the uses of compound_head() Vlastimil Babka
2021-02-26 19:04 ` Yu Zhao
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