On Thu, 11 May 2023 13:22:30 +0800 "zhaoyang.huang" <zhaoyang.huang@xxxxxxxxxx> wrote: > From: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx> > > Let us look at the timeline of scenarios below with WMARK_LOW=25MB WMARK_MIN=5MB > (managed pages 1.9GB). We can find that CMA begin to be used until 'C' under the > method of 'fixed 2 times of free cma over free pages' which could have the > scenario 'A' and 'B' into a fault state, that is, free UNMOVABLE & RECLAIMABLE > pages is lower than corresponding watermark without reclaiming which should be > deemed as against current memory policy. This commit try to solve this by > checking zone_watermark_ok again with removing CMA pages which could lead to a > proper time point of CMA's utilization. > > -- Free_pages > | > | > -- WMARK_LOW > | > -- Free_CMA > | > | > -- > > Free_CMA/Free_pages(MB) A(12/30) --> B(12/25) --> C(12/20) > fixed 1/2 ratio N N Y > this commit Y Y Y > Roman previously asked : Also I'm a bit concerned about potential performance implications. : Would be great to provide some benchmarks or some data. Probably it's : ok because of we have pcp caches on top, but I'm not 100% sure. Are you able to perform such testing and tell us the result? Thanks.
