On Fri 13-07-18 08:46:52, James Bottomley wrote: > On Fri, 2018-07-13 at 10:36 +1000, Dave Chinner wrote: > > On Thu, Jul 12, 2018 at 12:57:15PM -0700, James Bottomley wrote: > > > What surprises me most about this behaviour is the steadiness of > > > the page cache ... I would have thought we'd have shrunk it > > > somewhat given the intense call on the dcache. > > > > Oh, good, the page cache vs superblock shrinker balancing still > > protects the working set of each cache the way it's supposed to > > under heavy single cache pressure. :) > > Well, yes, but my expectation is most of the page cache is clean, so > easily reclaimable. I suppose part of my surprise is that I expected > us to reclaim the clean caches first before we started pushing out the > dirty stuff and reclaiming it. I'm not saying it's a bad thing, just > saying I didn't expect us to make such good decisions under the > parameters of this test. This is indeed unepxected. Especially when the current LRU reclaim balancing logic is highly pagecache biased. Are you sure you were not running in a memcg with a small amount of the pagecache? -- Michal Hocko SUSE Labs
