On Thu 22-09-16 09:13:50, zijun_hu wrote:

On 09/22/2016 08:35 AM, David Rientjes wrote:

[...]

quoted

The intent is as it is implemented; with your change, lazy_max_pages() is 
potentially increased depending on the number of online cpus.  This is 
only a heuristic, changing it would need justification on why the new 
value is better.  It is opposite to what the comment says: "to be 
conservative and not introduce a big latency on huge systems, so go with
a less aggressive log scale."  NACK to the patch.

my change potentially make lazy_max_pages() decreased not increased, i seems
conform with the comment

if the number of online CPUs is not power of 2, both have no any difference
otherwise, my change remain power of 2 value, and the original code rounds up
to next power of 2 value, for instance

my change : (32, 64] -> 64
	     32 -> 32, 64 -> 64
the original code: [32, 63) -> 64
                   32 -> 64, 64 -> 128

You still completely failed to explain _why_ this is an improvement/fix
or why it matters. This all should be in the changelog.

-- 
Michal Hocko
SUSE Labs

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