Re: MADV_DONTNEED semantics? Was: [RFC PATCH] mm: madvise: Ignore repeated MADV_DONTNEED hints
From: Michal Hocko <hidden>
Date: 2015-02-03 15:21:28
Also in:
linux-man, linux-mm, lkml
On Tue 03-02-15 11:16:00, Mel Gorman wrote:
On Tue, Feb 03, 2015 at 09:19:15AM +0100, Vlastimil Babka wrote:
[...]
quoted
And if we agree that there is indeed no guarantee, what's the actual semantic difference from MADV_FREE? I guess none? So there's only a possible perfomance difference?Timing. MADV_DONTNEED if it has an effect is immediate, is a heavier operations and RSS is reduced. MADV_FREE only has an impact in the future if there is memory pressure.
JFTR. the man page for MADV_FREE has been proposed already (https://lkml.org/lkml/2014/12/5/63 should be the last version AFAIR). I do not see it in the man-pages git tree but the patch was not in time for 3.19 so I guess it will only appear in 3.20. -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html