Re: [RFC 1/7] mm: introduce MADV_COOL

On Mon 20-05-19 10:16:21, Michal Hocko wrote:

[CC linux-api]

On Mon 20-05-19 12:52:48, Minchan Kim wrote:

quoted

When a process expects no accesses to a certain memory range
it could hint kernel that the pages can be reclaimed
when memory pressure happens but data should be preserved
for future use.  This could reduce workingset eviction so it
ends up increasing performance.

This patch introduces the new MADV_COOL hint to madvise(2)
syscall. MADV_COOL can be used by a process to mark a memory range
as not expected to be used in the near future. The hint can help
kernel in deciding which pages to evict early during memory
pressure.

I do not want to start naming fight but MADV_COOL sounds a bit
misleading. Everybody thinks his pages are cool ;). Probably MADV_COLD
or MADV_DONTNEED_PRESERVE.

OK, I can see that you have used MADV_COLD for a different mode.
So this one is effectively a non destructive MADV_FREE alternative
so MADV_FREE_PRESERVE would sound like a good fit. Your MADV_COLD
in other patch would then be MADV_DONTNEED_PRESERVE. Right?

-- 
Michal Hocko
SUSE Labs