Suspend-to-RAM and dirty page cache

Martinus2u · 03-18-2012, 04:29 AM

Hi,

in a nutshell: I sometimes find dirty pages in the output of /proc/meminfo immediately after resuming. That bothers me. Because if theses pages were left dirty during the suspended period, a powercut may lead to file system inconsistencies and what not.

Question: is there reason for concern, or have these dirty pages been created after the resume event?

Details: Slackware current, XFCE4 with cairo dock, no swap device. Even an explicit sync and sleep before the suspend action seems not to change the observation of dirty pages. Currently the suspend action is triggered by the following script:

Code:

#!/bin/bash
aplay /usr/share/sounds/purple/logout.wav &
sync
sleep 5
xfce4-session-logout --suspend

Martinus2u · 03-18-2012, 05:07 AM

Update: when monitoring the dirty pages via

Code:

while sleep 0 ; do cat /proc/meminfo | grep Dirty ; done

it appears that the machine indeed wakes up with 0 dirty pages but then immediately starts building them up. So probably all is well.