[PATCH 2/8] blk-mq: protect completion path with RCU

2018-01-09 Thread Tejun Heo
Currently, blk-mq protects only the issue path with RCU. This patch puts the completion path under the same RCU protection. This will be used to synchronize issue/completion against timeout by later patches, which will also add the comments. Signed-off-by: Tejun Heo ---

Re: [PATCH 2/8] blk-mq: protect completion path with RCU

2018-01-09 Thread Jens Axboe
On 1/9/18 9:19 AM, t...@kernel.org wrote: > Hello, Bart. > > On Tue, Jan 09, 2018 at 04:12:40PM +, Bart Van Assche wrote: >> I'm concerned about the additional CPU cycles needed for the new >> blk_mq_map_queue() >> call, although I know this call is cheap. Would the timeout code really get

Re: [PATCH 2/8] blk-mq: protect completion path with RCU

2018-01-09 Thread t...@kernel.org
Hello, Bart. On Tue, Jan 09, 2018 at 04:12:40PM +, Bart Van Assche wrote: > I'm concerned about the additional CPU cycles needed for the new > blk_mq_map_queue() > call, although I know this call is cheap. Would the timeout code really get > that So, if that is really a concern, let's

Re: [PATCH 2/8] blk-mq: protect completion path with RCU

2018-01-09 Thread Jens Axboe
On 1/9/18 9:12 AM, Bart Van Assche wrote: > On Mon, 2018-01-08 at 11:15 -0800, Tejun Heo wrote: >> Currently, blk-mq protects only the issue path with RCU. This patch >> puts the completion path under the same RCU protection. This will be >> used to synchronize issue/completion against timeout

Re: [PATCH 2/8] blk-mq: protect completion path with RCU

2018-01-09 Thread Bart Van Assche
On Mon, 2018-01-08 at 11:15 -0800, Tejun Heo wrote: > Currently, blk-mq protects only the issue path with RCU. This patch > puts the completion path under the same RCU protection. This will be > used to synchronize issue/completion against timeout by later patches, > which will also add the

Re: [PATCH 2/8] blk-mq: protect completion path with RCU

2018-01-09 Thread Jens Axboe
On 1/9/18 12:08 AM, Hannes Reinecke wrote: > On 01/08/2018 08:15 PM, Tejun Heo wrote: >> Currently, blk-mq protects only the issue path with RCU. This patch >> puts the completion path under the same RCU protection. This will be >> used to synchronize issue/completion against timeout by later

Re: [PATCH 2/8] blk-mq: protect completion path with RCU

2018-01-08 Thread Hannes Reinecke
On 01/08/2018 08:15 PM, Tejun Heo wrote: > Currently, blk-mq protects only the issue path with RCU. This patch > puts the completion path under the same RCU protection. This will be > used to synchronize issue/completion against timeout by later patches, > which will also add the comments. > >

Re: [PATCH 2/8] blk-mq: protect completion path with RCU

2018-01-08 Thread Holger Hoffstätte
On 01/09/18 00:27, Holger Hoffstätte wrote: > On 01/08/18 23:55, Jens Axboe wrote: >> the good old >> >> int srcu_idx = srcu_idx; >> >> should get the job done. > > (Narrator: It didn't.) Narrator: we retract our previous statement and apologize for the confusion. It works fine when you

Re: [PATCH 2/8] blk-mq: protect completion path with RCU

2018-01-08 Thread Holger Hoffstätte
On 01/08/18 23:55, Jens Axboe wrote: > On 1/8/18 1:15 PM, Jens Axboe wrote: >> On 1/8/18 12:57 PM, Holger Hoffstätte wrote: >>> On 01/08/18 20:15, Tejun Heo wrote: Currently, blk-mq protects only the issue path with RCU. This patch puts the completion path under the same RCU protection.

Re: [PATCH 2/8] blk-mq: protect completion path with RCU

2018-01-08 Thread Jens Axboe
On 1/8/18 1:15 PM, Jens Axboe wrote: > On 1/8/18 12:57 PM, Holger Hoffstätte wrote: >> On 01/08/18 20:15, Tejun Heo wrote: >>> Currently, blk-mq protects only the issue path with RCU. This patch >>> puts the completion path under the same RCU protection. This will be >>> used to synchronize

Re: [PATCH 2/8] blk-mq: protect completion path with RCU

2018-01-08 Thread Jens Axboe
On 1/8/18 12:57 PM, Holger Hoffstätte wrote: > On 01/08/18 20:15, Tejun Heo wrote: >> Currently, blk-mq protects only the issue path with RCU. This patch >> puts the completion path under the same RCU protection. This will be >> used to synchronize issue/completion against timeout by later

Re: [PATCH 2/8] blk-mq: protect completion path with RCU

2018-01-08 Thread Holger Hoffstätte
On 01/08/18 20:15, Tejun Heo wrote: > Currently, blk-mq protects only the issue path with RCU. This patch > puts the completion path under the same RCU protection. This will be > used to synchronize issue/completion against timeout by later patches, > which will also add the comments. > >

[PATCH 2/8] blk-mq: protect completion path with RCU

2018-01-08 Thread Tejun Heo
Currently, blk-mq protects only the issue path with RCU. This patch puts the completion path under the same RCU protection. This will be used to synchronize issue/completion against timeout by later patches, which will also add the comments. Signed-off-by: Tejun Heo ---