Re: [PATCH 03/17] mm: page_alloc: Use jump labels to avoid checking number_of_cpusets

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wed, May 07, 2014 at 11:04:21AM +0200, Peter Zijlstra wrote:
> On Tue, May 06, 2014 at 11:21:18PM +0100, Mel Gorman wrote:
> > On Tue, May 06, 2014 at 10:23:50PM +0200, Peter Zijlstra wrote:
> 
> > > Why the HAVE_JUMP_LABEL and number_of_cpusets thing? When
> > > !HAVE_JUMP_LABEL the static_key thing reverts to an atomic_t and
> > > static_key_false() becomes:
> > > 
> > 
> > Because number_of_cpusets is used to size a kmalloc(). Potentially I could
> > abuse the internals of static keys and use the value of key->enabled but
> > that felt like abuse of the API.
> 
> But are those ifdefs worth the saving of 4 bytes of .data?
> 
> That said, I see no real problem adding static_key_count().

I thought it would be considered API abuse as I always viewed the labels
as being a enabled/disabled thing with the existence of the ref count
being an internal implementation detail. I'll take this approach.

Thanks.

-- 
Mel Gorman
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [Samba]     [Device Mapper]     [CEPH Development]
  Powered by Linux