Date: Mon, 30 Oct 2006 22:09:46 +0100
From: Eric Dumazet <dada1@cosmosbay.com>
Subject: Re: [PATCH] vmalloc : optimization, cleanup, bugfixes
In-reply-to: <Pine.LNX.4.64.0610301234500.20628@montezuma.fsmlabs.com>
To: Zwane Mwaikambo <zwane@infradead.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>, Andrew Morton <akpm@osdl.org>,
       linux-kernel@vger.kernel.org
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Zwane Mwaikambo a ?crit :
> On Mon, 23 Oct 2006, Nick Piggin wrote:
> 
>> Eric Dumazet wrote:
>>> [PATCH] vmalloc : optimization, cleanup, bugfixes
>>>
>>> This patch does three things
>>>
>>> 1) reorder 'struct vm_struct' to speedup lookups on CPUS with small cache
>>> lines. The fields 'next,addr,size' should be now in the same cache line, to
>>> speedup lookups.
>>>
>>> 2) One minor cleanup in __get_vm_area_node()
>>>
>>> 3) Bugfixes in vmalloc_user() and vmalloc_32_user()
>>> NULL returns from __vmalloc() and __find_vm_area() were not tested.
>> Hmm, so they weren't. As far as testing the return of __find_vm_area,
>> you can just turn that into a BUG_ON(!area), because at that point,
>> we've established that the vmalloc succeeded.
> 
> No need for a BUG_ON it'll simply be a NULL dereference, at which point 
> we're back to the original code.

Indeed

This is what Andrew said one week ago :)

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