similar to: [PATCH 2/5] stop_machine: yield CPU during stop machine

Some time ago commit 57f2ffe14fd125c2 ("s390: remove diag 44 calls from cpu_relax()") did stop cpu_relax on s390 yielding to the hypervisor. As it turns out this made stop_machine run really slow on virtualized overcommited systems. For example the kprobes test during bootup took several seconds instead of just running unnoticed with large guests. Therefore, the yielding was

On Fri, 21 Oct 2016 14:05:36 +0200 Peter Zijlstra <peterz at infradead.org> wrote: > On Fri, Oct 21, 2016 at 01:58:55PM +0200, Christian Borntraeger wrote: > > stop_machine can take a very long time if the hypervisor does > > overcommitment for guest CPUs. When waiting for "the one", lets > > give up our CPU by using the new cpu_relax_yield. > > This

On 10/22/2016 02:06 AM, Nicholas Piggin wrote: > On Fri, 21 Oct 2016 14:05:36 +0200 > Peter Zijlstra <peterz at infradead.org> wrote: > >> On Fri, Oct 21, 2016 at 01:58:55PM +0200, Christian Borntraeger wrote: >>> stop_machine can take a very long time if the hypervisor does >>> overcommitment for guest CPUs. When waiting for "the one", lets

Peter, here is v2 with some improved patch descriptions and some fixes. The previous version has survived one day of linux-next and I only changed small parts. So unless there is some other issue, feel free to pull (or to apply the patches) to tip/locking. The following changes since commit 07d9a380680d1c0eb51ef87ff2eab5c994949e69: Linux 4.9-rc2 (2016-10-23 17:10:14 -0700) are available in

Peter, here is v2 with some improved patch descriptions and some fixes. The previous version has survived one day of linux-next and I only changed small parts. So unless there is some other issue, feel free to pull (or to apply the patches) to tip/locking. The following changes since commit 07d9a380680d1c0eb51ef87ff2eab5c994949e69: Linux 4.9-rc2 (2016-10-23 17:10:14 -0700) are available in

If stop_machine() invoked while one of onlined cpu is locked up by some reason, stop_machine cannot finish its work because the locked cpu cannot stop. This means all other healthy cpus will be blocked infinitely by one dead cpu. This patch allows stop_machine to return -EBUSY with some printk messages if any of stop_machine's threads cannot start running on its target cpu in time. You can

If stop_machine() invoked while one of onlined cpu is locked up by some reason, stop_machine cannot finish its work because the locked cpu cannot stop. This means all other healthy cpus will be blocked infinitely by one dead cpu. This patch allows stop_machine to return -EBUSY with some printk messages if any of stop_machine's threads cannot start running on its target cpu in time. You can

Thank you for useful feedbacks! Here is the updated version. Could you put this on top of your patches, Rusty? Thanks, H.Seto If stop_machine() invoked while one of onlined cpu is locked up by some reason, stop_machine cannot finish its work because the locked cpu cannot stop. This means all other healthy cpus will be blocked infinitely by one dead cpu. This patch allows stop_machine to

Thank you for useful feedbacks! Here is the updated version. Could you put this on top of your patches, Rusty? Thanks, H.Seto If stop_machine() invoked while one of onlined cpu is locked up by some reason, stop_machine cannot finish its work because the locked cpu cannot stop. This means all other healthy cpus will be blocked infinitely by one dead cpu. This patch allows stop_machine to

On kvm I have seen some rare hangs in stop_machine when I used more guest cpus than hosts cpus. e.g. 32 guest cpus on 1 host cpu triggered the hang quite often. I could also reproduce the problem on a 4 way z/VM host with a 64 way guest. It turned out that the guest was consuming all available cpus mostly for spinning on scheduler locks like rq->lock. This is expected as the threads are

On kvm I have seen some rare hangs in stop_machine when I used more guest cpus than hosts cpus. e.g. 32 guest cpus on 1 host cpu triggered the hang quite often. I could also reproduce the problem on a 4 way z/VM host with a 64 way guest. It turned out that the guest was consuming all available cpus mostly for spinning on scheduler locks like rq->lock. This is expected as the threads are

On 06/15/2014 06:17 PM, Peter Zijlstra wrote: > Signed-off-by: Peter Zijlstra<peterz at infradead.org> > --- [...] > + > +void kvm_wait(int *ptr, int val) > +{ > + unsigned long flags; > + > + if (in_nmi()) > + return; > + > + /* > + * Make sure an interrupt handler can't upset things in a > + * partially setup state. > + */ I am seeing hang

On 06/15/2014 06:17 PM, Peter Zijlstra wrote: > Signed-off-by: Peter Zijlstra<peterz at infradead.org> > --- [...] > + > +void kvm_wait(int *ptr, int val) > +{ > + unsigned long flags; > + > + if (in_nmi()) > + return; > + > + /* > + * Make sure an interrupt handler can't upset things in a > + * partially setup state. > + */ I am seeing hang

This is the last use of (the deprecated) stop_machine_run in the tree. Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> diff -r 332ec042cb4d drivers/xen/manage.c --- a/drivers/xen/manage.c Wed Aug 13 10:48:27 2008 +1000 +++ b/drivers/xen/manage.c Wed Aug 13 15:50:02 2008 +1000 @@ -102,7 +102,7 @@ static void do_suspend(void) /* XXX use normal device tree? */ xenbus_suspend();

I'm not sure if I should bother you team with this, apologies in case it's a bother. I'm trying gcc 6.2.1 (from devtoolset-6) with R, everything seems to work just fine, except for mzR. Here is failed build: g++ -m64 -shared -L/usr/lib64/R/lib -Wl,-z,relro -o mzR.so cramp.o ramp_base64.o ramp.o RcppRamp.o RcppRampModule.o rnetCDF.o RcppPwiz.o RcppPwizModule.o RcppIdent.o

On Tue, Apr 07, 2020 at 10:02:57PM -0700, Ankur Arora wrote: > A KVM host (or another hypervisor) might advertise paravirtualized > features and optimization hints (ex KVM_HINTS_REALTIME) which might > become stale over the lifetime of the guest. For instance, the > host might go from being undersubscribed to being oversubscribed > (or the other way round) and it would make sense

On Tue, Apr 07, 2020 at 10:02:57PM -0700, Ankur Arora wrote: > A KVM host (or another hypervisor) might advertise paravirtualized > features and optimization hints (ex KVM_HINTS_REALTIME) which might > become stale over the lifetime of the guest. For instance, the > host might go from being undersubscribed to being oversubscribed > (or the other way round) and it would make sense

I do this on a vanilla-clean R installation, simply: > biocLite("mzR") it pulls some deps in which compile fine, only mzR fails. ... meanwhile... I grabbed devtools and comiled github master - still fails. Should I attach build log? One should not send attachments to the list.. I don't suppose? On 21/12/16 17:06, Martin Morgan wrote: > mzR is a Bioconductor package, so

No need to duplicate the same define everywhere. Since the only user is stop-machine and the only provider is s390, we can use a default implementation of cpu_relax_yield in sched.h. Suggested-by: Russell King <linux at armlinux.org.uk> Signed-off-by: Christian Borntraeger <borntraeger at de.ibm.com> --- arch/alpha/include/asm/processor.h | 1 - arch/arc/include/asm/processor.h

No need to duplicate the same define everywhere. Since the only user is stop-machine and the only provider is s390, we can use a default implementation of cpu_relax_yield in sched.h. Suggested-by: Russell King <linux at armlinux.org.uk> Signed-off-by: Christian Borntraeger <borntraeger at de.ibm.com> --- arch/alpha/include/asm/processor.h | 1 - arch/arc/include/asm/processor.h