Re: [Xen-devel] [RFC PATCH] docs: add README.atomic

2017-06-16 Thread Jan Beulich
>>> On 15.06.17 at 19:21, wrote: > On 14/06/17 10:12, Jan Beulich wrote: > On 13.06.17 at 17:25, wrote: >>> @@ -0,0 +1,116 @@ >>> +Atomic operations in Xen >>> + >>> + >>> +Data structures in Xen memory which can be

Re: [Xen-devel] [RFC PATCH] docs: add README.atomic

2017-06-15 Thread Stefano Stabellini
On Thu, 15 Jun 2017, Jan Beulich wrote: > >>> Stefano Stabellini 06/15/17 2:27 AM >>> > >On Wed, 14 Jun 2017, Jan Beulich wrote: > >> >>> Stefano Stabellini 06/14/17 8:45 PM >>> > >> >On Wed, 14 Jun 2017, Jan Beulich wrote: > >> >> > +What

Re: [Xen-devel] [RFC PATCH] docs: add README.atomic

2017-06-15 Thread Andre Przywara
Hi Jan, thanks for spending your time on this mind boggling exercise! On 14/06/17 10:12, Jan Beulich wrote: On 13.06.17 at 17:25, wrote: >> as mentioned in my previous mail, I consider this more of a discussion >> base that an actual patch. I am by no means an

Re: [Xen-devel] [RFC PATCH] docs: add README.atomic

2017-06-15 Thread Jan Beulich
>>> Stefano Stabellini 06/15/17 2:27 AM >>> >On Wed, 14 Jun 2017, Jan Beulich wrote: >> >>> Stefano Stabellini 06/14/17 8:45 PM >>> >> >On Wed, 14 Jun 2017, Jan Beulich wrote: >> >> > +What ACCESS_ONCE does *not* guarantee though is this access is

Re: [Xen-devel] [RFC PATCH] docs: add README.atomic

2017-06-14 Thread Stefano Stabellini
On Wed, 14 Jun 2017, Jan Beulich wrote: > >>> Stefano Stabellini 06/14/17 8:45 PM >>> > >On Wed, 14 Jun 2017, Jan Beulich wrote: > >> > +What ACCESS_ONCE does *not* guarantee though is this access is done in a > >> > +single instruction, so complex or non-native or

Re: [Xen-devel] [RFC PATCH] docs: add README.atomic

2017-06-14 Thread Jan Beulich
>>> Stefano Stabellini 06/14/17 8:45 PM >>> >On Wed, 14 Jun 2017, Jan Beulich wrote: >> > +What ACCESS_ONCE does *not* guarantee though is this access is done in a >> > +single instruction, so complex or non-native or unaligned data types are >> > +not guaranteed to be

Re: [Xen-devel] [RFC PATCH] docs: add README.atomic

2017-06-14 Thread Stefano Stabellini
On Wed, 14 Jun 2017, Jan Beulich wrote: > > +What ACCESS_ONCE does *not* guarantee though is this access is done in a > > +single instruction, so complex or non-native or unaligned data types are > > +not guaranteed to be atomic. If for instance counter would be a 64-bit > > value > > +on a

Re: [Xen-devel] [RFC PATCH] docs: add README.atomic

2017-06-14 Thread Jan Beulich
>>> On 13.06.17 at 17:25, wrote: > as mentioned in my previous mail, I consider this more of a discussion > base that an actual patch. I am by no means an expert in this area, so > part of this exercise here is to write down my understanding and see it > corrected by more

Re: [Xen-devel] [RFC PATCH] docs: add README.atomic

2017-06-13 Thread Stefano Stabellini
On Tue, 13 Jun 2017, Andre Przywara wrote: > Recently there were some discussions about the nature and guarantees of > the atomic primitives that Xen provides. > This README.atomic file tries to document our expectations in those > functions and macros. > > Signed-off-by: Andre Przywara

[Xen-devel] [RFC PATCH] docs: add README.atomic

2017-06-13 Thread Andre Przywara
Recently there were some discussions about the nature and guarantees of the atomic primitives that Xen provides. This README.atomic file tries to document our expectations in those functions and macros. Signed-off-by: Andre Przywara --- Hi, as mentioned in my previous