[lkml]   [2006]   [Aug]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC][PATCH 4/4] Rename lock_cpu_hotplug/unlock_cpu_hotplug
Arjan van de Ven wrote:
> On Thu, 2006-08-24 at 19:33 +0530, Gautham R Shenoy wrote:
>>On Thu, Aug 24, 2006 at 01:00:00PM +0200, Arjan van de Ven wrote:
>>>On Thu, 2006-08-24 at 16:04 +0530, Gautham R Shenoy wrote:
>>>>This patch renames lock_cpu_hotplug to cpu_hotplug_disable and
>>>>unlock_cpu_hotplug to cpu_hotplug_enable throughout the kernel.
>>>to be honest I dislike the new names too. You turned it into a refcount,
>>>which is good, but the normal linux name for such refcount functions is
>>>_get and _put..... and in addition the refcount technically isn't
>>>hotplug specific, all you want is to keep the kernel data for the
>>>processor as being "used", so cpu_get() and cpu_put() would sound
>>>reasonable names to me, or cpu_data_get() cpu_data_put().
>>Thus, choice of 'cpu_hotplug_disable' and 'cpu_hotplug_enable'
>>was determined on the basis of its purpose, as in *what* it does
>>as opposed to *how* it does it. :)
> well.. it comes down to the difference of locking to protect data versus
> locking to protect against a specific piece of code. Almost always the
> later turns out to be a mistake...

But it is not protecting a cpu from going away, it is protecting ALL
cpus from coming or leaving. In that respect it is much more like a
cpu_online_map lock rather than a data structure refcount.

It really is just like a reentrant rw semaphore... I don't see the
point of the name change, but I guess we don't like reentrant locks so
calling it something else might go down better with Linus ;)

SUSE Labs, Novell Inc.
Send instant messages to your online friends

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2006-08-24 16:59    [W:0.106 / U:1.272 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site