Messages in this thread | | | Date | Fri, 19 Mar 2010 10:51:32 +0900 | From | Tejun Heo <> | Subject | Re: [BUG] percpu misaligned allocation |
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Hello,
On 03/19/2010 10:31 AM, Frederic Weisbecker wrote: > On Thu, Mar 18, 2010 at 05:54:13PM -0700, David Miller wrote: >> From: Tejun Heo <tj@kernel.org> >> Date: Thu, 18 Mar 2010 18:30:34 +0900 >> >>> >>> if (!total_profile_count) { >>> - buf = (char *)alloc_percpu(perf_trace_t); >>> + buf = (char *)__alloc_percpu(sizeof(perf_trace_t), >>> + __alignof__(unsigned long)); >>> if (!buf) >>> goto fail_buf; >> >> Why not make perf_trace_t have the proper alignment?
Sure, I just wanted to verify the cause of the problem.
> So, making perf_trace_t as align(8) would do the trick? > I lack the knowledge about alignment layout for archs that > need aligned accesses.
If you can't make it a proper type, __alignof__(unsigned long long) would be better.
> Yeah but we need a generic type. This is because > our buffer can be of any random type to match all > the trace event layouts we have, all of them being > generated by macros.
I hope those macros align properly according to types.
Thanks.
-- tejun
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