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

[Michal Hocko]

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:
> > 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