The patch titled
Subject: swap: add a limit for readahead page-cluster value
has been added to the -mm mm-unstable branch. Its filename is
swap-add-a-limit-for-readahead-page-cluster-value.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/swap-add-a-limit-for-readahead-page-cluster-value.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Kairui Song <kasong@xxxxxxxxxxx>
Subject: swap: add a limit for readahead page-cluster value
Date: Mon, 24 Oct 2022 00:25:33 +0800
Currenty there is no upper limit for /proc/sys/vm/page-cluster, and it's a
bit shift value, so it could result in overflow of the 32-bit integer.
Add a reasonable upper limit for it, read-in at most 2**31 pages, which is
a large enough value for readahead.
Link: https://lkml.kernel.org/r/20221023162533.81561-1-ryncsn@xxxxxxxxx
Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm.h | 1 +
kernel/sysctl.c | 1 +
mm/swap.c | 3 ++-
3 files changed, 4 insertions(+), 1 deletion(-)
--- a/include/linux/mm.h~swap-add-a-limit-for-readahead-page-cluster-value
+++ a/include/linux/mm.h
@@ -74,6 +74,7 @@ static inline void totalram_pages_add(lo
extern void * high_memory;
extern int page_cluster;
+extern const int page_cluster_max;
#ifdef CONFIG_SYSCTL
extern int sysctl_legacy_va_layout;
--- a/kernel/sysctl.c~swap-add-a-limit-for-readahead-page-cluster-value
+++ a/kernel/sysctl.c
@@ -2125,6 +2125,7 @@ static struct ctl_table vm_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
+ .extra2 = (void *)&page_cluster_max,
},
{
.procname = "dirtytime_expire_seconds",
--- a/mm/swap.c~swap-add-a-limit-for-readahead-page-cluster-value
+++ a/mm/swap.c
@@ -43,8 +43,9 @@
#define CREATE_TRACE_POINTS
#include <trace/events/pagemap.h>
-/* How many pages do we try to swap or page in/out together? */
+/* How many pages do we try to swap or page in/out together? As a power of 2 */
int page_cluster;
+const int page_cluster_max = 31;
/* Protecting only lru_rotate.fbatch which requires disabling interrupts */
struct lru_rotate {
_
Patches currently in -mm which might be from kasong@xxxxxxxxxxx are
swap-add-a-limit-for-readahead-page-cluster-value.patch
