Messages in this thread | | | Subject | Re: computing drop-able caches | From | Rik van Riel <> | Date | Fri, 29 Jan 2016 17:41:43 -0500 |
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On 01/28/2016 08:55 PM, Johannes Weiner wrote: > On Thu, Jan 28, 2016 at 05:29:41PM -0800, Daniel Walker wrote: >> On 01/28/2016 05:03 PM, Daniel Walker wrote: >> [regarding MemAvaiable] >> >> This new metric purportedly helps usrespace assess available memory. But, >> its again based on heuristic, it takes 1/2 of page cache as reclaimable.. > > No, it takes the smaller value of cache/2 and the low watermark, which > is a fraction of memory. Actually, that does look a little weird. Rik?
No, not quite. The page cache calculation spans two lines:
pagecache = pages[LRU_ACTIVE_FILE] + pages[LRU_INACTIVE_FILE]; pagecache -= min(pagecache / 2, wmark_low);
The assumption is that ALL of active & inactive file LRUs are freeable, except for the minimum of the low watermark, or half the page cache.
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