Re: [PATCH] ACPI/osl: speedup grace period in acpi_os_map_cleanup

2014-11-09 Thread Konstantin Khlebnikov
On Sun, Nov 9, 2014 at 3:51 AM, Paul E. McKenney wrote: > On Sun, Nov 09, 2014 at 03:24:34AM +0400, Alexander Monakov wrote: >> On Sun, Nov 9, 2014 at 1:13 AM, Paul E. McKenney >> wrote: >> > >> > Did anyone try replacing the synchronize_rcu() with >> > synchronize_rcu_expedited()? That should p

Re: [PATCH] ACPI/osl: speedup grace period in acpi_os_map_cleanup

2014-11-08 Thread Paul E. McKenney
On Sun, Nov 09, 2014 at 03:24:34AM +0400, Alexander Monakov wrote: > On Sun, Nov 9, 2014 at 1:13 AM, Paul E. McKenney > wrote: > > > > Did anyone try replacing the synchronize_rcu() with > > synchronize_rcu_expedited()? That should provide substantial speedups > > over synchronize_rcu(). > > I'v

Re: [PATCH] ACPI/osl: speedup grace period in acpi_os_map_cleanup

2014-11-08 Thread Alexander Monakov
On Sun, Nov 9, 2014 at 1:13 AM, Paul E. McKenney wrote: > > Did anyone try replacing the synchronize_rcu() with > synchronize_rcu_expedited()? That should provide substantial speedups > over synchronize_rcu(). I've just briefly tested it on my laptop, and it also helps to avoid the issue. Alexa

Re: [PATCH] ACPI/osl: speedup grace period in acpi_os_map_cleanup

2014-11-08 Thread Paul E. McKenney
On Sat, Nov 08, 2014 at 12:47:17PM +0400, Konstantin Khlebnikov wrote: > ACPI maintains cache of ioremap regions to speed up operations and > access to them from irq context where ioremap() calls aren't allowed. > This code abuses synchronize_rcu() on unmap path for synchronization > with fast-path

[PATCH] ACPI/osl: speedup grace period in acpi_os_map_cleanup

2014-11-08 Thread Konstantin Khlebnikov
ACPI maintains cache of ioremap regions to speed up operations and access to them from irq context where ioremap() calls aren't allowed. This code abuses synchronize_rcu() on unmap path for synchronization with fast-path in acpi_os_read/write_memory which uses this cache. Since v3.10 CPUs are allo