Thread (61 messages) 61 messages, 8 authors, 2012-10-29

Re: [PATCH v7 06/16] tracepoint: use new hashtable implementation

From: Tejun Heo <hidden>
Date: 2012-10-29 19:01:15
Also in: dm-devel, linux-mm, linux-nfs, lkml

On Mon, Oct 29, 2012 at 11:58:14AM -0700, Tejun Heo wrote:
On Mon, Oct 29, 2012 at 02:53:19PM -0400, Mathieu Desnoyers wrote:
quoted
The argument about hash_init being useful to add magic values in the
future only works for the cases where a hash table is declared with
DECLARE_HASHTABLE(). It's completely pointless with DEFINE_HASHTABLE(),
because we could initialize any debugging variables from within
DEFINE_HASHTABLE().
You can do that with [0 .. HASH_SIZE - 1] initializer.
And in general, let's please try not to do optimizations which are
pointless.  Just stick to the usual semantics.  You have an abstract
data structure - invoke the initializer before using it.  Sure,
optimize it if it shows up somewhere.  And here, if we do the
initializers properly, it shouldn't cause any more actual overhead -
ie. DEFINE_HASHTABLE() will basicallly boil down to all zero
assignments and the compiler will put the whole thing in .bss anyway.

Thanks.

-- 
tejun
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