Messages in this thread |  | | | Subject | Re: [BUG] 2.6.37-rc3 massive interactivity regression on ARM | | From | Eric Dumazet <> | | Date | Fri, 10 Dec 2010 19:14:19 +0100 |
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Le vendredi 10 décembre 2010 à 18:49 +0100, Peter Zijlstra a écrit : > On Fri, 2010-12-10 at 18:18 +0100, Eric Dumazet wrote: > > Le vendredi 10 décembre 2010 à 14:47 +0100, Peter Zijlstra a écrit : > > > Also irq_time_write_begin() and irq_time_write_end() could be faster > > (called for current cpu) > > > > static inline void irq_time_write_begin(void) > > { > > __this_cpu_inc(irq_time_seq.sequence); > > smp_wmb(); > > } > > > > static inline void irq_time_write_end(void) > > { > > smp_wmb(); > > __this_cpu_inc(irq_time_seq.sequence); > > } > > Yeah, but that kinda defeats the purpose of having it implemented in > seqlock.h. Ideally we'd teach gcc about these long pointers and have > something like: > > write_seqcount_begin(&this_cpu_read(irq_time_seq)); > > do the right thing.
gcc wont be able to do this yet (%fs/%gs selectors)
But we can provide this_cpu_write_seqcount_{begin|end}() static inline void this_cpu_write_seqcount_begin(seqcount_t *s) { __this_cpu_inc(s->sequence); smp_wmb(); }
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