Re: [HPDD-discuss] OSC and buffer cache throttling
On Feb 3, 2015, at 3:58 PM, Patrick Farrell <paf(a)cray.com>
wrote:
Interesting that Rick's seeing 3/4 on his system. The limit looks to be < 512MB,
if I'm reading correctly.
I glanced at the Lustre source for my 2.5.3 client and found this:
pages = si.totalram - si.totalhigh;
if (pages >> (20 - PAGE_CACHE_SHIFT) < 512) {
lru_page_max = pages / 2;
} else {
lru_page_max = (pages / 4) * 3;
}
The way I am reading this is that if the system has <512MB of memory, the lru_page_max
is 1/2 the system RAM. Otherwise, it will be 3/4 of the system RAM.
--
Rick Mohr
Senior HPC System Administrator
National Institute for Computational Sciences
http://www.nics.tennessee.edu