2008-03-23 03:24:45 pagecache_ratio on 2008R1-RC8

David Rowe (AUSTRALIA)

Message: 52933 Hi,

Is /proc/sys/vm/pagecache_ratio available on uClinux-dist-2008R1-RC8? I cant seem to see any sign of it in the kernel sources. This was quite useful in uClinux-dist-2007 to prevent cached file data using up all the system memory over time. Perhaps it has been replaced by a different method?

Thanks,

David

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2008-03-23 14:19:49 Re: pagecache_ratio on 2008R1-RC8

Robin Getz (UNITED STATES)

Message: 52937 David:

Yeah, we came to the conclusion that limiting the size of the page cache was actually the wrong way to fix the problem - so now we just reap the page cache (dump pages) in low memory conditions. Hopefully, it actually works better.

-Robin

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2008-03-23 17:04:05 Re: pagecache_ratio on 2008R1-RC8

David Rowe (AUSTRALIA)

Message: 52942 Automatic reaping sounds like a good plan Robin.

I am currently testing FreePBX on 2008R1-RC8, which is a memory-intensive GUI front end for Asterisk that uses php. It's currently a little less stable that the same code on 2007R1.1, e.g. I am getting core dump type messages like:

php-cgi invoked oom-killer: gfp_mask=0x40d0, order=9, oomkilladj=0

Then Asterisk gets killed (not php-cgi curiously). This is with top and free reporting about 24M free, 5M allocated to caches. On 2007R1.1, I had about 10M free and could run the same code without any core dumps. However it's early days, I may have missed something in the set up.

Is there anyway to get more info on what applications are requesting memory, like a log of the memory manager's activities? Perhaps I could run strace on php-cgi, and look for the mmap calls.

Thanks,

David

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2008-03-23 18:48:32 Re: pagecache_ratio on 2008R1-RC8

Mike Frysinger (UNITED STATES)

Message: 52944 /proc/maps and /proc/<pid>/maps contains all allocations