Re: [PATCH] blk-mq: use __smp_call_function_single directly

2014-01-09 Thread Jens Axboe
On Thu, Jan 09 2014, Christoph Hellwig wrote: > On Wed, Jan 08, 2014 at 02:31:15PM -0700, Jens Axboe wrote: > > On 01/08/2014 10:33 AM, Christoph Hellwig wrote: > > > __smp_call_function_single already avoids multiple IPIs by internally > > > queing up the items, and now also is available for non-S

Re: [PATCH] blk-mq: use __smp_call_function_single directly

2014-01-09 Thread Christoph Hellwig
On Wed, Jan 08, 2014 at 02:31:15PM -0700, Jens Axboe wrote: > On 01/08/2014 10:33 AM, Christoph Hellwig wrote: > > __smp_call_function_single already avoids multiple IPIs by internally > > queing up the items, and now also is available for non-SMP builds as > > a trivially correct stub, so there is

Re: [PATCH] blk-mq: use __smp_call_function_single directly

2014-01-08 Thread Jens Axboe
On 01/08/2014 10:33 AM, Christoph Hellwig wrote: > __smp_call_function_single already avoids multiple IPIs by internally > queing up the items, and now also is available for non-SMP builds as > a trivially correct stub, so there is no need to wrap it. If the > additional lock roundtrip cause probl

[PATCH] blk-mq: use __smp_call_function_single directly

2014-01-08 Thread Christoph Hellwig
__smp_call_function_single already avoids multiple IPIs by internally queing up the items, and now also is available for non-SMP builds as a trivially correct stub, so there is no need to wrap it. If the additional lock roundtrip cause problems my patch to convert the generic IPI code to llists is