[RFC][PATCHv2 2/8] zsmalloc: partial page ordering within a fullness_list

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From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>,
	Minchan Kim <minchan@kernel.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Subject: [RFC][PATCHv2 2/8] zsmalloc: partial page ordering within a fullness_list
Date: Fri,  5 Jun 2015 21:03:52 +0900	[thread overview]
Message-ID: <1433505838-23058-3-git-send-email-sergey.senozhatsky@gmail.com> (raw)
In-Reply-To: <1433505838-23058-1-git-send-email-sergey.senozhatsky@gmail.com>

We want to see more ZS_FULL pages and less ZS_ALMOST_{FULL, EMPTY}
pages. Put a page with higher ->inuse count first within its
->fullness_list, which will give us better chances to fill up this
page with new objects (find_get_zspage() return ->fullness_list head
for new object allocation), so some zspages will become
ZS_ALMOST_FULL/ZS_FULL quicker.

It performs a trivial and cheap ->inuse compare which does not slow
down zsmalloc, and in the worst case it keeps the list pages not in
any particular order, just like we do it now.

A more expensive solution could sort fullness_list by ->inuse count.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
---
 mm/zsmalloc.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index ce3310c..cd37bda 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -658,8 +658,16 @@ static void insert_zspage(struct page *page, struct size_class *class,
 		return;
 
 	head = &class->fullness_list[fullness];
-	if (*head)
-		list_add_tail(&page->lru, &(*head)->lru);
+	if (*head) {
+		/*
+		 * We want to see more ZS_FULL pages and less almost
+		 * empty/full. Put pages with higher ->inuse first.
+		 */
+		if (page->inuse < (*head)->inuse)
+			list_add_tail(&page->lru, &(*head)->lru);
+		else
+			list_add(&page->lru, &(*head)->lru);
+	}
 
 	*head = page;
 	zs_stat_inc(class, fullness == ZS_ALMOST_EMPTY ?
-- 
2.4.2.387.gf86f31a

WARNING: multiple messages have this Message-ID (diff)

From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>,
	Minchan Kim <minchan@kernel.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Subject: [RFC][PATCHv2 2/8] zsmalloc: partial page ordering within a fullness_list
Date: Fri,  5 Jun 2015 21:03:52 +0900	[thread overview]
Message-ID: <1433505838-23058-3-git-send-email-sergey.senozhatsky@gmail.com> (raw)
In-Reply-To: <1433505838-23058-1-git-send-email-sergey.senozhatsky@gmail.com>

We want to see more ZS_FULL pages and less ZS_ALMOST_{FULL, EMPTY}
pages. Put a page with higher ->inuse count first within its
->fullness_list, which will give us better chances to fill up this
page with new objects (find_get_zspage() return ->fullness_list head
for new object allocation), so some zspages will become
ZS_ALMOST_FULL/ZS_FULL quicker.

It performs a trivial and cheap ->inuse compare which does not slow
down zsmalloc, and in the worst case it keeps the list pages not in
any particular order, just like we do it now.

A more expensive solution could sort fullness_list by ->inuse count.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
---
 mm/zsmalloc.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index ce3310c..cd37bda 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -658,8 +658,16 @@ static void insert_zspage(struct page *page, struct size_class *class,
 		return;
 
 	head = &class->fullness_list[fullness];
-	if (*head)
-		list_add_tail(&page->lru, &(*head)->lru);
+	if (*head) {
+		/*
+		 * We want to see more ZS_FULL pages and less almost
+		 * empty/full. Put pages with higher ->inuse first.
+		 */
+		if (page->inuse < (*head)->inuse)
+			list_add_tail(&page->lru, &(*head)->lru);
+		else
+			list_add(&page->lru, &(*head)->lru);
+	}
 
 	*head = page;
 	zs_stat_inc(class, fullness == ZS_ALMOST_EMPTY ?
-- 
2.4.2.387.gf86f31a

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next prev parent reply	other threads:[~2015-06-05 12:04 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-05 12:03 [RFC][PATCHv2 0/8] introduce automatic pool compaction Sergey Senozhatsky
2015-06-05 12:03 ` Sergey Senozhatsky
2015-06-05 12:03 ` [RFC][PATCHv2 1/8] zsmalloc: drop unused variable `nr_to_migrate' Sergey Senozhatsky
2015-06-05 12:03   ` Sergey Senozhatsky
2015-06-05 12:03 ` Sergey Senozhatsky [this message]
2015-06-05 12:03   ` [RFC][PATCHv2 2/8] zsmalloc: partial page ordering within a fullness_list Sergey Senozhatsky
2015-06-16 13:19   ` Minchan Kim
2015-06-16 13:19     ` Minchan Kim
2015-06-16 14:30     ` Sergey Senozhatsky
2015-06-16 14:30       ` Sergey Senozhatsky
2015-06-05 12:03 ` [RFC][PATCHv2 3/8] zsmalloc: lower ZS_ALMOST_FULL waterline Sergey Senozhatsky
2015-06-05 12:03   ` Sergey Senozhatsky
2015-06-16 13:37   ` Minchan Kim
2015-06-16 13:37     ` Minchan Kim
2015-06-16 14:35     ` Sergey Senozhatsky
2015-06-16 14:35       ` Sergey Senozhatsky
2015-06-05 12:03 ` [RFC][PATCHv2 4/8] zsmalloc: always keep per-class stats Sergey Senozhatsky
2015-06-05 12:03   ` Sergey Senozhatsky
2015-06-05 12:03 ` [RFC][PATCHv2 5/8] zsmalloc: introduce zs_can_compact() function Sergey Senozhatsky
2015-06-05 12:03   ` Sergey Senozhatsky
2015-06-16 14:19   ` Minchan Kim
2015-06-16 14:19     ` Minchan Kim
2015-06-16 14:41     ` Sergey Senozhatsky
2015-06-16 14:41       ` Sergey Senozhatsky
2015-06-05 12:03 ` [RFC][PATCHv2 6/8] zsmalloc: cosmetic compaction code adjustments Sergey Senozhatsky
2015-06-05 12:03   ` Sergey Senozhatsky
2015-06-05 12:03 ` [RFC][PATCHv2 7/8] zsmalloc/zram: move `num_migrated' to zs_pool Sergey Senozhatsky
2015-06-05 12:03   ` Sergey Senozhatsky
2015-06-05 12:03 ` [RFC][PATCHv2 8/8] zsmalloc: register a shrinker to trigger auto-compaction Sergey Senozhatsky
2015-06-05 12:03   ` Sergey Senozhatsky
2015-06-16 14:47   ` Minchan Kim
2015-06-16 14:47     ` Minchan Kim
2015-06-16 15:45     ` Sergey Senozhatsky
2015-06-16 15:45       ` Sergey Senozhatsky
2015-06-18  1:50       ` Minchan Kim
2015-06-18  1:50         ` Minchan Kim
2015-06-18  2:41         ` Sergey Senozhatsky
2015-06-18  2:41           ` Sergey Senozhatsky
2015-06-18  3:01           ` Sergey Senozhatsky
2015-06-18  3:01             ` Sergey Senozhatsky
2015-06-18  3:46             ` Minchan Kim
2015-06-18  3:46               ` Minchan Kim
2015-06-18  3:39           ` Minchan Kim
2015-06-18  3:39             ` Minchan Kim
2015-06-18  3:58             ` Sergey Senozhatsky
2015-06-18  3:58               ` Sergey Senozhatsky
2015-06-17  7:11     ` Sergey Senozhatsky
2015-06-17  7:11       ` Sergey Senozhatsky
2015-06-10  0:04 ` [RFC][PATCHv2 0/8] introduce automatic pool compaction Minchan Kim
2015-06-10  0:04   ` Minchan Kim
2015-06-10  0:07   ` Sergey Senozhatsky
2015-06-10  0:07     ` Sergey Senozhatsky

find likely ancestor, descendant, or conflicting patches for this message:
dfblob:ce3310c dfblob:ce3310c dfblob:cd37bda dfblob:cd37bda
	(help)

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