Xu CanHao wrote:
Hello!
Since the default atom_max_size is RAM/4, that means 256MB of
maximum atom in your computer, and your HDD does 30MB/s which means
you'll have 8s-9s "flush/system freeze" time.
IIRC, edward said the atom_max_size mount option is useless,
It is useless for remount, in other cases it works fine
(for root file system it makes sense to edit fstab).
So you can pass the option "tmgr.atom_max_size=N",
where N is atom size in blocks
so
I'd suggest you modify your reiser4/init_super.c and change:
sbinfo->tmgr.atom_max_size = totalram_pages / 4;
to
sbinfo->tmgr.atom_max_size = totalram_pages / 16;
which means your atom would have a maximum size of 64MB and a maximum
freeze time of only 2 seconds.
Such nice linear dependency disappears with some workload,
so freeze time is not comforting also for small atoms..
Thanks!
2007/7/28, Zan Lynx <zlynx@xxxxxxx>:
Edward answered my question mostly.
But, I have 1 GB RAM and a Hitachi 7,200 RPM laptop drive. It does
about 30 MB/s.
On Fri, 2007-07-27 at 09:40 +0800, Xu CanHao wrote:
Hello!
How much is your RAM?
What is the result of your HDD's hdparm -t?
Thanks!
2007/7/27, Zan Lynx <zlynx@xxxxxxx>:
I have often experienced nearly full system freezes for up to five
seconds at a time while memory is being flushed to disk.
I'm not sure if this is a general Linux problem or a Reiser4 problem, so
I thought I'd ask.
A sysrq-T during the freeze shows many processes trying to acquire a
memory page, and Reiser4 flushing atoms and doing sync things.
My working theory right now is that Reiser4 spends time flushing a lot
of data at once before returning.
If I am right about that, would it not make more sense to flush a few
pages, return to the kernel, flush a few more pages, return to the
kernel, etc, etc? That way programs could get a bit of RAM and make
some progress.
Of course I could be completely off about what's going on.
--
Zan Lynx <zlynx@xxxxxxx>
--
Zan Lynx <zlynx@xxxxxxx>
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