2010-07-20 12:12:55

by Al Boldi

[permalink] [raw]
Subject: [Regression] mm: Huge swapout performance regression on recent kernels

I have noticed a big swapout performance regression on recent kernels using
the following testcase:

swapon /dev/md0 (raid0)
mount none /dev/shm -t tmpfs -o size=10G
cat /dev/full > /dev/shm/tst.dmp

Kernel starts to swapout at full speed after filling physical ram.
Then, kernel progressively slows down swapout after crossing the ~3G VM
threshold, compounding at over 50% slowdown when reaching the 10G tmpfs
limit.

Has this been fixed?


Thanks!

--
Al