Re: computing drop-able caches
From: Dave Hansen <hidden>
Date: 2016-02-12 21:46:54
Also in:
linux-fsdevel, lkml
On 02/12/2016 10:01 AM, Khalid Mughal (khalidm) wrote:
If you look at the attached pdf, you will notice that OOM messages start to appear when memAvailable is showing 253MB (259228 KB) Free, memFree is 13.5MB (14008 KB) Free, and dropcache based calculation 3Available memory2 is showing 21MB (21720 KB) Free. So, it appears that memAvailable is not as accurate, especially if data is used to warn user about system running low on memory.
Yep, that's true. But, MemAvailable is calculated from some very cheap counters. The "dropcache-based-calculation" requires iterating over every 4k page cache page in the system. Do you have some ideas for doing cheap(er) MemAvailable calculations? We track dirty and writebackw with counters, so we should theoretically be able to pull those out of MemAvailable fairly cheaply. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>