Well, 2.6.34-r1 is out and it contains patch under question. I've
managed to try in on a testbox and compare with 2.6.32-gentoo-r3 on a
x86_64 machine with 4G of ram
The file list is clean. After restart, adding a single 8G file causes ZERO
swapping, and the system stays responsive. With 2.6.32 swapping occurs
instantly when free memory reaches it's minimum and kswapd begins reclaiming
pages. The system becomes sluggish, mouse cursor jumps.
Overall hashing speed with the new kernel is very stable - 57Mb/s on my old
SATA drive. With 2.6.32, hashing speed is also very stable until kswapd steps
in - after that, hashing speed drops to ~50Mb/sec and oscillates around it.
When hashing thread is finished, new kernel still shows ZERO swap usage,
whereas 2.6.32 shows this:
$ free
total used free shared buffers cached
Mem: 4055264 4022896 32368 0 2952 3824016
-/+ buffers/cache: 195928 3859336
Swap: 2008084 122796 1885288
So, this post is not a confirmation of a problem resolution, more
testing is needed, and probably not until the patchset is backported on
2.6.33 series. Or, maybe, not until 2.6.34 is stable.
--
Excessive swapping during hash
https://bugs.launchpad.net/bugs/376896
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Status in Linux DC++: Incomplete
Bug description:
There is a reproducable problem in linuxdcpp (or maybe it is the kernel/libc?),
where hashing a large file causes excessive swapping to occur, while memory
usage is far from 100%. I've seen this on at least two different machines, both
working under gentoo amd64 and both using 2.6.29.2 kernel.
Steps to reproduce:
1. Start X/GNOME/KDE, some programs in the background to give system something
to swap
2. Start hashing some _big_ files (say, 2GIG and more on a system with 4GiGs of
RAM)
3. See swapping to occur
I don't know whether thisi is a kernel or stdlib or linuxdcpp issue, but I only
see such swapping with linuxdcpp
Here is a "vmstat 2" output during hashing of two big files in the attachment
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