On Fri 16 Feb 2007 at 01:12PM, Timo Sirainen wrote:
On Fri, 2007-02-16 at 03:05 -0800, Dan Price wrote:
On Fri 16 Feb 2007 at 02:49AM, Dan Price wrote:
So.. Hmm. Could the problem simply be that the mmap-copy-growing is too slow? If the user really has some 25MB cache file, that could be it. I think I could change the code so that it mmap()s immediately enough memory to fit the whole cache file. Probably a good idea to do anyway.
One thing I don't totally get is why you mmap anon here, if this is really about a cache file? It seems that you could mmap the cache file directly, perhaps with MAP_PRIVATE if you need to make in-memory-only changes.
Yes, and it's done as long as you don't have mmap_disable=yes. Hmm. Weren't you using ZFS directly? Why are you using mmap_disable=yes? :) Its main purpose is to make indexes work in NFS.
Well there you go, I'm a dope. I think I set mmap_disable=yes because I was seeing strange things happening where there would be thousands (millions?) of madvise(DONTNEED) calls-- seemingly forever in a loop. I have not yet tracked that problem down-- next time I see it, I will make sure to get to the bottom of it.
I must have decided that turning off mmap would also halt the advice... who knows, it has been a rough week. There's a lesson: know what the hell you are doing before changing settings :)
I will run tomorrow with mmap_disable=no and see how it goes.
-dp-- Daniel Price - Solaris Kernel Engineering - dp@eng.sun.com - blogs.sun.com/dp