Re: too big min_free_kbytes
From: Shaohua Li <hidden>
Date: 2011-02-25 00:51:53
On Thu, 2011-02-24 at 22:04 +0800, Andrea Arcangeli wrote:
On Thu, Feb 24, 2011 at 04:08:47PM +0800, Shaohua Li wrote:quoted
with madvise, the min_free_kbytes is still high (same as the 'always' case). The result is still we have about 50M memory is reserved. you can try at your machine with boot option 'mem=2G' and check the zoneinfo output.yes I know. The objective of that test was exactly to know if the problem is higher memory footprint because of THP or only the anti-frag/min_free_kbytes which would still be present with the "madvise" setting (anti-frag is only shutdown by the "never" setting). If you still have the out of memory with madvise, then you can keep THP enabled "always" and then "echo 16384 > /proc/sys/vm/min_free_kbytes", it should work fine then even with THP always mode then, no need to disable THP (simply you won't have a good guarantee that anti-frag is functional so the hugepage usage will be reduced over time compared to the default min_free_kbytes that enables anti-frag fully).
I can disable THP or set the min_free_kbytes manually in our test, but just wonder if it's possible we can avoid the memory waste even with THP enabled, because this will make more people enable it by default. If you don't consider this is a problem, we can disable THP. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>