similar to: [RFC PATCH 00/26] Runtime paravirt patching

On 08.04.20 14:08, Peter Zijlstra wrote: > On Tue, Apr 07, 2020 at 10:02:57PM -0700, Ankur Arora wrote: >> Mechanism: the patching itself is done using stop_machine(). That is >> not ideal -- text_poke_stop_machine() was replaced with INT3+emulation >> via text_poke_bp(), but I'm using this to address two issues: >> 1) emulation in text_poke() can only easily

On Tue, Apr 07, 2020 at 10:03:16PM -0700, Ankur Arora wrote: > @@ -1807,12 +1911,20 @@ static int __maybe_unused text_poke_late(patch_worker_t worker, void *stage) > text_poke_state.state = PATCH_SYNC_DONE; /* Start state */ > text_poke_state.primary_cpu = smp_processor_id(); > > + text_poke_state.nmi_context = nmi; > + > + if (nmi) > +

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 seems something that would apply to most other virt stuff. Lets Cc a few more lists for that. > Signed-off-by:

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 seems something that would apply to most other virt stuff. Lets Cc a few more lists for that. > Signed-off-by:

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

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

Btw., another question that made me wonder already when doing the original patch: why is it that x86-64 properly uses locking for mm_pin_all(), yet i386 doesn''t need to? Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel

On 08.04.20 07:02, 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 Then this hint is wrong if it can't be guaranteed. > host might go from being undersubscribed to being oversubscribed > (or the other way

This patch implements cpu offline feature. Best Regards Haitao Shan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel

On Wed, Jun 28, 2017 at 03:28:11PM +0200, Maarten Lankhorst wrote: > We want to change swap_state to wait indefinitely, but to do this > swap_state should wait interruptibly. This requires propagating > the error to each driver. All drivers have changes to deal with the > clean up. In order to allow easy reverting, the commit that changes > behavior is separate so someone only has

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();

Patch 1 removes CONFIG_SMP Patch 2 removes separate smp_{,r,w}mb()s as a result of patch 1 Patch 4 removes __ia64__ defines from the x86 arch tree Patch 3 is related to patch 4 and changes the VIOAPIC to emulate version 0x20 as a performance gain. It preceeds Patch 4 so as to be more clear about the functional change. Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

When in SYS_STATE_suspend, and going through the cpu_disable_scheduler path, save a copy of the current cpu affinity, and mark a flag to restore it later. Later, in the resume process, when enabling nonboot cpus restore these affinities. v2: Fix formatting problems. remove early return in cpu_disable_scheduler() path. v3: Fix remaining errant tab Move restore_vcpu_affinity() to thaw_domains(),

We want to change swap_state to wait indefinitely, but to do this swap_state should wait interruptibly. This requires propagating the error to each driver. All drivers have changes to deal with the clean up. In order to allow easy reverting, the commit that changes behavior is separate so someone only has to revert that for testing. Nouveau has a small bugfix, if drm_atomic_helper_wait_for_fences

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