[Devel] [PATCH RHEL7 COMMIT] mm/vmscan: make sysctl_vm_force_scan_thresh 100 by default

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-693.1.1.vz7.37.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-693.1.1.vz7.37.30
------>
commit 8f06bff58da9e0b2a887a22675ceb2cc6a4523f8
Author: Andrey Ryabinin <aryabinin at virtuozzo.com>
Date:   Tue Nov 28 13:45:02 2017 +0300

    mm/vmscan: make sysctl_vm_force_scan_thresh 100 by default
    
    force_scan was invented for very narrow case. It hurts us badly
    when we have one cgroup that consumes almost all memory and few
    small ones.
    
    Set sysctl_vm_force_scan_thresh to 100 by default which effectively
    disables it.
    
    https://jira.sw.ru/browse/PSBM-77547
    Signed-off-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
    
    khorenko@: exact usecase: vStorage cgroup with CS's running inside
    is a big cgroup, it generates a lot of pagecache.
    Small cgroup - "system" which contains "systemd" and effectively
    swap out "systemd".
---
 mm/vmscan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index e13a71e..524d1452 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1919,7 +1919,7 @@ static int vmscan_swappiness(struct scan_control *sc)
 }
 
 #ifdef CONFIG_MEMCG
-int sysctl_force_scan_thresh = 50;
+int sysctl_force_scan_thresh = 100;
 
 static inline bool zone_force_scan(struct zone *zone)
 {