Messages in this thread | | | Date | Tue, 5 Jul 2011 21:56:09 +0400 | From | Cyrill Gorcunov <> | Subject | Re: [Q x86-64] on kernel_eflags |
| |
On Tue, Jul 05, 2011 at 10:47:10AM -0700, H. Peter Anvin wrote: > On 07/05/2011 03:47 AM, Cyrill Gorcunov wrote: > > > > Should not every cpu has own copy of kernel_eflags? Just > > to be consistent in style? Or this would be space waisting > > and an optimization is done here? > > > > Not specific to this particular case, but in general: a shared variable > that used often but rarely written to will automatically replicate > itself in the caches of multiple processors. This is the purpose of the > read_mostly segment (writes are permitted but expected to be rare), > which exists to make sure that a frequently written variable doesn't > randomly end up in the cache line next to a read-mostly variable. > > -hpa >
yeah, thanks peter!
Cyrill
| |