Messages in this thread | | | Date | Sun, 01 May 2011 06:36:05 +0800 | From | Wu Fengguang <> | Subject | [PATCH 0/3] sync livelock fixes |
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Andrew,
I wrote a simple script to test sync livelock and this patchset is working as expected:
sync time: 2 Dirty: 26492 kB Writeback: 30260 kB NFS_Unstable: 0 kB WritebackTmp: 0 kB sync NOT livelocked
In particular patch 2 fixes the sync livelock problem introduced by patch "writeback: try more writeback as long as something was written".
Thanks, Fengguang ---
#!/bin/sh
umount /dev/sda7 # mkfs.xfs -f /dev/sda7 mkfs.ext4 /dev/sda7 mount /dev/sda7 /fs
echo $((50<<20)) > /proc/sys/vm/dirty_bytes
pid= for i in `seq 10` do dd if=/dev/zero of=/fs/zero-$i bs=1M count=1000 & pid="$pid $!" done
sleep 1
tic=$(date +'%s') sync tac=$(date +'%s')
echo echo sync time: $((tac-tic)) egrep '(Dirty|Writeback|NFS_Unstable)' /proc/meminfo
pidof dd > /dev/null && { kill -9 $pid; echo sync NOT livelocked; }
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