From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ed White Subject: Re: [PATCH v2 09/12] x86/altp2m: add remaining support routines. Date: Fri, 26 Jun 2015 09:30:10 -0700 Message-ID: <558D7E12.7080904@intel.com> References: <1434999372-3688-1-git-send-email-edmund.h.white@intel.com> <1434999372-3688-10-git-send-email-edmund.h.white@intel.com> <558AB4D3.4030805@citrix.com> <558AED2B.6030409@intel.com> <558AF495.7010101@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <558AF495.7010101@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Andrew Cooper , xen-devel@lists.xen.org Cc: Ravi Sahita , Wei Liu , Tim Deegan , Ian Jackson , Jan Beulich , tlengyel@novetta.com, Daniel De Graaf List-Id: xen-devel@lists.xenproject.org On 06/24/2015 11:19 AM, Andrew Cooper wrote: > On 24/06/15 18:47, Ed White wrote: >>>> This looks like some hoop jumping around the assertions in >>>> domain_pause() and vcpu_pause(). >>>> >>>> We should probably have some new helpers where the domain needs to be >>>> paused, possibly while in context. The current domain/vcpu_pause() are >>>> almost always used where it is definitely not safe to pause in context, >>>> hence the assertions. >>>> >> It is. I'd be happy to use new helpers, I don't feel qualified to >> write them. >> >> Ed > > Something like this? Only compile tested. In the meantime, I have an > optimisation in mind for domain_pause() on domains with large numbers of > vcpus, but that will have to wait a while. > > From: Andrew Cooper > Date: Wed, 24 Jun 2015 19:06:14 +0100 > Subject: [PATCH] common/domain: Helpers to pause a domain while in context > > For use on codepaths which would need to use domain_pause() but might be in > the target domain's context. In the case that the target domain is in > context, > all other vcpus are paused. > > Signed-off-by: Andrew Cooper > --- > xen/common/domain.c | 28 ++++++++++++++++++++++++++++ > xen/include/xen/sched.h | 5 +++++ > 2 files changed, 33 insertions(+) > > diff --git a/xen/common/domain.c b/xen/common/domain.c > index 3bc52e6..a1d27e3 100644 > --- a/xen/common/domain.c > +++ b/xen/common/domain.c > @@ -1010,6 +1010,34 @@ int domain_unpause_by_systemcontroller(struct > domain *d) > return 0; > } > > +void domain_pause_except_self(struct domain *d) > +{ > + struct vcpu *v, *curr = current; > + > + if ( curr->domain == d ) > + { > + for_each_vcpu( d, v ) > + if ( likely(v != curr) ) > + vcpu_pause(v); > + } > + else > + domain_pause(d); > +} > + > +void domain_unpause_except_self(struct domain *d) > +{ > + struct vcpu *v, *curr = current; > + > + if ( curr->domain == d ) > + { > + for_each_vcpu( d, v ) > + if ( likely(v != curr) ) > + vcpu_unpause(v); > + } > + else > + domain_unpause(d); > +} > + > int vcpu_reset(struct vcpu *v) > { > struct domain *d = v->domain; > diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h > index b29d9e7..8e1345a 100644 > --- a/xen/include/xen/sched.h > +++ b/xen/include/xen/sched.h > @@ -804,6 +804,11 @@ static inline int > domain_pause_by_systemcontroller_nosync(struct domain *d) > { > return __domain_pause_by_systemcontroller(d, domain_pause_nosync); > } > + > +/* domain_pause() but safe against trying to pause current. */ > +void domain_pause_except_self(struct domain *d); > +void domain_unpause_except_self(struct domain *d); > + > void cpu_init(void); > > struct scheduler; > > Did you commit this to staging? IOW, can I apply it to my branch and assume it will already be in-tree when our patches are applied? Ed