From: Johannes Weiner <hannes@cmpxchg.org>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
Rik van Riel <riel@redhat.com>, Mel Gorman <mgorman@suse.de>,
Andrea Arcangeli <aarcange@redhat.com>,
Andi Kleen <andi@firstfloor.org>, Michal Hocko <mhocko@suse.cz>,
Tim Chen <tim.c.chen@linux.intel.com>,
kernel-team@fb.com
Subject: [PATCH 01/10] mm: allow swappiness that prefers anon over file
Date: Mon, 6 Jun 2016 15:48:27 -0400 [thread overview]
Message-ID: <20160606194836.3624-2-hannes@cmpxchg.org> (raw)
In-Reply-To: <20160606194836.3624-1-hannes@cmpxchg.org>
With the advent of fast random IO devices (SSDs, PMEM) and in-memory
swap devices such as zswap, it's possible for swap to be much faster
than filesystems, and for swapping to be preferable over thrashing
filesystem caches.
Allow setting swappiness - which defines the relative IO cost of cache
misses between page cache and swap-backed pages - to reflect such
situations by making the swap-preferred range configurable.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
---
Documentation/sysctl/vm.txt | 16 +++++++++++-----
kernel/sysctl.c | 3 ++-
mm/vmscan.c | 2 +-
3 files changed, 14 insertions(+), 7 deletions(-)
diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
index 720355cbdf45..54030750cd31 100644
--- a/Documentation/sysctl/vm.txt
+++ b/Documentation/sysctl/vm.txt
@@ -771,14 +771,20 @@ with no ill effects: errors and warnings on these stats are suppressed.)
swappiness
-This control is used to define how aggressive the kernel will swap
-memory pages. Higher values will increase agressiveness, lower values
-decrease the amount of swap. A value of 0 instructs the kernel not to
-initiate swap until the amount of free and file-backed pages is less
-than the high water mark in a zone.
+This control is used to define the relative IO cost of cache misses
+between the swap device and the filesystem as a value between 0 and
+200. At 100, the VM assumes equal IO cost and will thus apply memory
+pressure to the page cache and swap-backed pages equally. At 0, the
+kernel will not initiate swap until the amount of free and file-backed
+pages is less than the high watermark in a zone.
The default value is 60.
+On non-rotational swap devices, a value of 100 (or higher, depending
+on what's backing the filesystem) is recommended.
+
+For in-memory swap, like zswap, values closer to 200 are recommended.
+
==============================================================
- user_reserve_kbytes
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 2effd84d83e3..56a9243eb171 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -126,6 +126,7 @@ static int __maybe_unused two = 2;
static int __maybe_unused four = 4;
static unsigned long one_ul = 1;
static int one_hundred = 100;
+static int two_hundred = 200;
static int one_thousand = 1000;
#ifdef CONFIG_PRINTK
static int ten_thousand = 10000;
@@ -1323,7 +1324,7 @@ static struct ctl_table vm_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &zero,
- .extra2 = &one_hundred,
+ .extra2 = &two_hundred,
},
#ifdef CONFIG_HUGETLB_PAGE
{
diff --git a/mm/vmscan.c b/mm/vmscan.c
index c4a2f4512fca..f79010bbcdd4 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -136,7 +136,7 @@ struct scan_control {
#endif
/*
- * From 0 .. 100. Higher means more swappy.
+ * From 0 .. 200. Higher means more swappy.
*/
int vm_swappiness = 60;
/*
--
2.8.3
next prev parent reply other threads:[~2016-06-06 19:53 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-06 19:48 [PATCH 00/10] mm: balance LRU lists based on relative thrashing Johannes Weiner
2016-06-06 19:48 ` Johannes Weiner [this message]
2016-06-07 0:25 ` [PATCH 01/10] mm: allow swappiness that prefers anon over file Minchan Kim
2016-06-07 14:18 ` Johannes Weiner
2016-06-08 0:06 ` Minchan Kim
2016-06-08 15:58 ` Johannes Weiner
2016-06-09 1:01 ` Minchan Kim
2016-06-09 13:32 ` Johannes Weiner
2016-06-06 19:48 ` [PATCH 02/10] mm: swap: unexport __pagevec_lru_add() Johannes Weiner
2016-06-06 21:32 ` Rik van Riel
2016-06-07 9:07 ` Michal Hocko
2016-06-08 7:14 ` Minchan Kim
2016-06-06 19:48 ` [PATCH 03/10] mm: fold and remove lru_cache_add_anon() and lru_cache_add_file() Johannes Weiner
2016-06-06 21:33 ` Rik van Riel
2016-06-07 9:12 ` Michal Hocko
2016-06-08 7:24 ` Minchan Kim
2016-06-06 19:48 ` [PATCH 04/10] mm: fix LRU balancing effect of new transparent huge pages Johannes Weiner
2016-06-06 21:36 ` Rik van Riel
2016-06-07 9:19 ` Michal Hocko
2016-06-08 7:28 ` Minchan Kim
2016-06-06 19:48 ` [PATCH 05/10] mm: remove LRU balancing effect of temporary page isolation Johannes Weiner
2016-06-06 21:56 ` Rik van Riel
2016-06-06 22:15 ` Johannes Weiner
2016-06-07 1:11 ` Rik van Riel
2016-06-07 13:57 ` Johannes Weiner
2016-06-07 9:26 ` Michal Hocko
2016-06-07 14:06 ` Johannes Weiner
2016-06-07 9:49 ` Michal Hocko
2016-06-08 7:39 ` Minchan Kim
2016-06-08 16:02 ` Johannes Weiner
2016-06-06 19:48 ` [PATCH 06/10] mm: remove unnecessary use-once cache bias from LRU balancing Johannes Weiner
2016-06-07 2:20 ` Rik van Riel
2016-06-07 14:11 ` Johannes Weiner
2016-06-08 8:03 ` Minchan Kim
2016-06-08 12:31 ` Michal Hocko
2016-06-06 19:48 ` [PATCH 07/10] mm: base LRU balancing on an explicit cost model Johannes Weiner
2016-06-06 19:13 ` kbuild test robot
2016-06-07 2:34 ` Rik van Riel
2016-06-07 14:12 ` Johannes Weiner
2016-06-08 8:14 ` Minchan Kim
2016-06-08 16:06 ` Johannes Weiner
2016-06-08 12:51 ` Michal Hocko
2016-06-08 16:16 ` Johannes Weiner
2016-06-09 12:18 ` Michal Hocko
2016-06-09 13:33 ` Johannes Weiner
2016-06-06 19:48 ` [PATCH 08/10] mm: deactivations shouldn't bias the LRU balance Johannes Weiner
2016-06-08 8:15 ` Minchan Kim
2016-06-08 12:57 ` Michal Hocko
2016-06-06 19:48 ` [PATCH 09/10] mm: only count actual rotations as LRU reclaim cost Johannes Weiner
2016-06-08 8:19 ` Minchan Kim
2016-06-08 13:18 ` Michal Hocko
2016-06-06 19:48 ` [PATCH 10/10] mm: balance LRU lists based on relative thrashing Johannes Weiner
2016-06-06 19:22 ` kbuild test robot
2016-06-06 23:50 ` Tim Chen
2016-06-07 16:23 ` Johannes Weiner
2016-06-07 19:56 ` Tim Chen
2016-06-08 13:58 ` Michal Hocko
2016-06-10 2:19 ` Minchan Kim
2016-06-13 15:52 ` Johannes Weiner
2016-06-15 2:23 ` Minchan Kim
2016-06-16 15:12 ` Johannes Weiner
2016-06-17 7:49 ` Minchan Kim
2016-06-17 17:01 ` Johannes Weiner
2016-06-20 7:42 ` Minchan Kim
2016-06-22 21:56 ` Johannes Weiner
2016-06-24 6:22 ` Minchan Kim
2016-06-07 9:51 ` [PATCH 00/10] " Michal Hocko
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