Re: [Patch] Scale pidhash_shift/pidhash_size up based on num_possible_cpus().

From: Eric W. Biederman
Date: Thu Jul 31 2008 - 18:13:25 EST


Robin Holt <holt@xxxxxxx> writes:

> Like so???
>
> I have not tested this yet.

Looks reasonable to me.

In what circumstances was the lookup in the pid hash table with
long changes causing a performance slowdown?. We don't perform
a lot of lookups.


> - pidhash_shift = min(12, pidhash_shift);
> + pidhash_shift = min(fls(PID_MAX_LIMIT) - 6, pidhash_shift);
> pidhash_size = 1 << pidhash_shift;
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