Re: computing drop-able caches
From: Rik van Riel <hidden>
Date: 2016-01-29 22:41:43
Also in:
linux-fsdevel, lkml
On 01/28/2016 08:55 PM, Johannes Weiner wrote:
On Thu, Jan 28, 2016 at 05:29:41PM -0800, Daniel Walker wrote:quoted
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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