vm.min_free_kbytes / is it per CPU setting?
From: Vajra
Date: Mon Jul 31 2006 - 12:50:29 EST
Hi,
I set vm.min_free_kbytes=65536 in /etc/sysctl.conf and rebooted.
After reboot, I transferred 4GB DVD iso images from FTP server
on local lan and monitored mem usage with vmstat.
...
procs -----------memory---------- ---swap-- -----io---- --system--
----cpu----
r b swpd free buff cache si so bi bo in cs us sy
id wa
0 0 0 151520 4456 1854324 0 0 0 12276 13533 16275 1 17
82 1
1 0 0 139864 4472 1865868 0 0 0 12472 13438 16237 1 16
83 0
1 0 0 128080 4480 1877352 0 0 0 12160 13449 16298 1 17
82 0
0 0 0 127360 2668 1879640 0 0 12 8420 13380 16285 1 18
70 11
1 0 0 128488 832 1880932 0 0 0 12436 13397 16192 2 18
81 0
1 0 700 128116 840 1880700 0 0 4 12224 13490 16233 1 18
80 0
0 0 956 127620 856 1880836 0 0 0 12564 13436 16227 1 17
82 0
1 0 1212 127856 868 1880432 0 0 24 12112 13478 16306 1 17
81 2
1 0 1468 128104 876 1879896 0 0 0 8292 13416 16272 1 18
81 0
1 0 1980 128104 884 1879376 0 0 0 12480 13442 16184 1 17
82 0
1 0 2236 128104 892 1879248 0 0 16 12432 13399 16212 1 18
80 0
1 0 2400 127852 888 1879156 0 0 0 12440 13472 16244 1 17
82 0
1 0 2400 127728 888 1879088 0 0 0 12436 13390 16280 1 18
81 0
1 0 2432 127852 896 1878844 0 0 16 8336 13489 16280 0 17
81 1
1 0 2440 127620 900 1879240 0 0 0 12432 13464 16250 1 17
83 0
...
It looks like the kernel tried to maintain 128KB of free mem instead of
keeping 64KB of free mem as I expected. Is that normal? If it is, why?
I'm using Mandriva 2006 on a dual Xeon 2.4GHz, 2GB RAM system.
Kernel version is 2.6.12-24mdk, and I recompiled the source to include
needed drivers and features only.
-- Vajra
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