similar to: [PATCH] Fix preemptible lazy mode bug

Hi, when creating a bigger (> 50 GB) HVM guest with maxmem > memory we get softlockups from time to time. kernel: [ 802.084335] BUG: soft lockup - CPU#1 stuck for 22s! [xend:31351] I tracked this down to the call of xc_domain_set_pod_target() and further p2m_pod_set_mem_target(). Unfortunately I can this check only with xen-4.2.2 as I don''t have a machine with enough memory for

As a follow up to https://reviews.llvm.org/D20217 I would like to use lto/thinlto to refine when a symbol is marked as local/preemptable. I'm not very familiar with lto though so would appreciate some guidance about how best to go about this. Regards Sean Fertile

On Tue 16-06-20 17:37:11, Matthew Wilcox wrote: > On Wed, Jun 17, 2020 at 01:01:30AM +0200, David Sterba wrote: > > On Tue, Jun 16, 2020 at 11:53:50AM -0700, Joe Perches wrote: > > > On Mon, 2020-06-15 at 21:57 -0400, Waiman Long wrote: > > > > v4: > > > > - Break out the memzero_explicit() change as suggested by Dan Carpenter > > > > so

On Tue 16-06-20 17:37:11, Matthew Wilcox wrote: > On Wed, Jun 17, 2020 at 01:01:30AM +0200, David Sterba wrote: > > On Tue, Jun 16, 2020 at 11:53:50AM -0700, Joe Perches wrote: > > > On Mon, 2020-06-15 at 21:57 -0400, Waiman Long wrote: > > > > v4: > > > > - Break out the memzero_explicit() change as suggested by Dan Carpenter > > > > so

Hi, I am profiling some workloads for the voluntary and involuntary context switches. I am interested in finding out the reasons causing these two types of context switches. As far as I understand, involuntary context switch happens on expiration of time slice or when a higher priority process comes in. While the voluntary switch generally happens when a process is waiting for I/O etc. So to

Hi, I'm in the process of migrating from clang5 to clang10. Unfortunately clang10 introduced a negative performance impact. The cause is an increase of PLT entries from this patch (first released in clang7): https://bugs.llvm.org/show_bug.cgi?id=36370 https://reviews.llvm.org/D43383 If I revert that clang patch locally, the additional PLT entries and the performance impact disappear. This

On Wed 17-06-20 04:08:20, Matthew Wilcox wrote: > On Wed, Jun 17, 2020 at 09:12:12AM +0200, Michal Hocko wrote: > > On Tue 16-06-20 17:37:11, Matthew Wilcox wrote: > > > Not just performance critical, but correctness critical. Since kvfree() > > > may allocate from the vmalloc allocator, I really think that kvfree() > > > should assert that it's

On Wed 17-06-20 04:08:20, Matthew Wilcox wrote: > On Wed, Jun 17, 2020 at 09:12:12AM +0200, Michal Hocko wrote: > > On Tue 16-06-20 17:37:11, Matthew Wilcox wrote: > > > Not just performance critical, but correctness critical. Since kvfree() > > > may allocate from the vmalloc allocator, I really think that kvfree() > > > should assert that it's

Found this looping Ubuntu installs with VMI. If unlucky enough to hit a vmalloc sync fault during a lazy mode = operation (from an IRQ handler for a module which was not yet populated = in current page directory, or from inside copy_one_pte, which touches = swap_map, and hit in an unused 4M region), the required PDE update would = never get flushed, causing an infinite page fault loop. This

Found this looping Ubuntu installs with VMI. If unlucky enough to hit a vmalloc sync fault during a lazy mode = operation (from an IRQ handler for a module which was not yet populated = in current page directory, or from inside copy_one_pte, which touches = swap_map, and hit in an unused 4M region), the required PDE update would = never get flushed, causing an infinite page fault loop. This

Following up to the discussion in: https://lore.kernel.org/r/20200914204209.256266093 at linutronix.de and the second version of this: https://lore.kernel.org/r/20201029221806.189523375 at linutronix.de this series provides a preemptible variant of kmap_atomic & related interfaces. This is achieved by: - Removing the RT dependency from migrate_disable/enable() - Consolidating all

Following up to the discussion in: https://lore.kernel.org/r/20200914204209.256266093 at linutronix.de and the second version of this: https://lore.kernel.org/r/20201029221806.189523375 at linutronix.de this series provides a preemptible variant of kmap_atomic & related interfaces. This is achieved by: - Removing the RT dependency from migrate_disable/enable() - Consolidating all

Following up to the discussion in: https://lore.kernel.org/r/20200914204209.256266093 at linutronix.de and the second version of this: https://lore.kernel.org/r/20201029221806.189523375 at linutronix.de this series provides a preemptible variant of kmap_atomic & related interfaces. This is achieved by: - Removing the RT dependency from migrate_disable/enable() - Consolidating all

Jeremy Fitzhardinge wrote: > Andrew Morton wrote: > > On Thu, 15 Feb 2007 22:14:45 -0800 Dan Hecht > <dhecht@vmware.com> wrote: > > > > > >>> config PREEMPT > >>> bool "Preemptible Kernel (Low-Latency Desktop)" > >>> + depends on !XEN > >>> help > >>> This option reduces the latency of

Jeremy Fitzhardinge wrote: > Andrew Morton wrote: > > On Thu, 15 Feb 2007 22:14:45 -0800 Dan Hecht > <dhecht@vmware.com> wrote: > > > > > >>> config PREEMPT > >>> bool "Preemptible Kernel (Low-Latency Desktop)" > >>> + depends on !XEN > >>> help > >>> This option reduces the latency of

Jeremy Fitzhardinge wrote: > Andrew Morton wrote: > > On Thu, 15 Feb 2007 22:14:45 -0800 Dan Hecht > <dhecht@vmware.com> wrote: > > > > > >>> config PREEMPT > >>> bool "Preemptible Kernel (Low-Latency Desktop)" > >>> + depends on !XEN > >>> help > >>> This option reduces the latency of

On Sat, May 25, 2019 at 10:54:50AM +0200, Juergen Gross wrote: > On 25/05/2019 10:22, Nadav Amit wrote: > > diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h > > index 946f8f1f1efc..3a156e63c57d 100644 > > --- a/arch/x86/include/asm/paravirt_types.h > > +++ b/arch/x86/include/asm/paravirt_types.h > > @@ -211,6 +211,12 @@

On Sat, May 25, 2019 at 10:54:50AM +0200, Juergen Gross wrote: > On 25/05/2019 10:22, Nadav Amit wrote: > > diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h > > index 946f8f1f1efc..3a156e63c57d 100644 > > --- a/arch/x86/include/asm/paravirt_types.h > > +++ b/arch/x86/include/asm/paravirt_types.h > > @@ -211,6 +211,12 @@

Currently, the set_lazy_mode pv_op is overloaded with 5 functions: 1. enter lazy cpu mode 2. leave lazy cpu mode 3. enter lazy mmu mode 4. leave lazy mmu mode 5. flush pending batched operations This complicates each paravirt backend, since it needs to deal with all the possible state transitions, handling flushing, etc. In particular, flushing is quite distinct from the other 4 functions,

Currently, the set_lazy_mode pv_op is overloaded with 5 functions: 1. enter lazy cpu mode 2. leave lazy cpu mode 3. enter lazy mmu mode 4. leave lazy mmu mode 5. flush pending batched operations This complicates each paravirt backend, since it needs to deal with all the possible state transitions, handling flushing, etc. In particular, flushing is quite distinct from the other 4 functions,