Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

* Michal Hocko [230123 15:00]: > On Mon 23-01-23 19:30:43, Matthew Wilcox wrote: > > On Mon, Jan 23, 2023 at 08:18:37PM +0100, Michal Hocko wrote: > > > On Mon 23-01-23 18:23:08, Matthew Wilcox wrote: > > > > On Mon, Jan 23, 2023 at 09:46:20AM -0800, Suren Baghdasaryan wrote: > > > [...] > > > >

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Mon, Jan 23, 2023 at 12:00 PM Michal Hocko wrote: > > On Mon 23-01-23 19:30:43, Matthew Wilcox wrote: > > On Mon, Jan 23, 2023 at 08:18:37PM +0100, Michal Hocko wrote: > > > On Mon 23-01-23 18:23:08, Matthew Wilcox wrote: > > > > On Mon, Jan 23, 2023 at 09:46:20AM -0800, Suren Baghdasaryan

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Mon 23-01-23 19:30:43, Matthew Wilcox wrote: > On Mon, Jan 23, 2023 at 08:18:37PM +0100, Michal Hocko wrote: > > On Mon 23-01-23 18:23:08, Matthew Wilcox wrote: > > > On Mon, Jan 23, 2023 at 09:46:20AM -0800, Suren Baghdasaryan wrote: > > [...] > > > > Yes, batching the vmas into a list and

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Mon, Jan 23, 2023 at 11:31 AM Matthew Wilcox wrote: > > On Mon, Jan 23, 2023 at 08:18:37PM +0100, Michal Hocko wrote: > > On Mon 23-01-23 18:23:08, Matthew Wilcox wrote: > > > On Mon, Jan 23, 2023 at 09:46:20AM -0800, Suren Baghdasaryan wrote: > > [...] > > > > Yes, batching the vmas into a

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Mon, Jan 23, 2023 at 08:18:37PM +0100, Michal Hocko wrote: > On Mon 23-01-23 18:23:08, Matthew Wilcox wrote: > > On Mon, Jan 23, 2023 at 09:46:20AM -0800, Suren Baghdasaryan wrote: > [...] > > > Yes, batching the vmas into a list and draining it in remove_mt() and > > > exit_mmap() as you

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Mon 23-01-23 18:23:08, Matthew Wilcox wrote: > On Mon, Jan 23, 2023 at 09:46:20AM -0800, Suren Baghdasaryan wrote: [...] > > Yes, batching the vmas into a list and draining it in remove_mt() and > > exit_mmap() as you suggested makes sense to me and is quite simple. > > Let's do that if nobody

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Mon, Jan 23, 2023 at 10:23 AM Matthew Wilcox wrote: > > On Mon, Jan 23, 2023 at 09:46:20AM -0800, Suren Baghdasaryan wrote: > > On Mon, Jan 23, 2023 at 9:16 AM Michal Hocko wrote: > > > > > > On Mon 23-01-23 09:07:34, Suren Baghdasaryan wrote: > > > > On Mon, Jan 23, 2023 at 8:55 AM Michal

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Mon, Jan 23, 2023 at 09:46:20AM -0800, Suren Baghdasaryan wrote: > On Mon, Jan 23, 2023 at 9:16 AM Michal Hocko wrote: > > > > On Mon 23-01-23 09:07:34, Suren Baghdasaryan wrote: > > > On Mon, Jan 23, 2023 at 8:55 AM Michal Hocko wrote: > > > > > > > > On Mon 23-01-23 08:22:53, Suren

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Mon, Jan 23, 2023 at 9:16 AM Michal Hocko wrote: > > On Mon 23-01-23 09:07:34, Suren Baghdasaryan wrote: > > On Mon, Jan 23, 2023 at 8:55 AM Michal Hocko wrote: > > > > > > On Mon 23-01-23 08:22:53, Suren Baghdasaryan wrote: > > > > On Mon, Jan 23, 2023 at 1:56 AM Michal Hocko wrote: > > > >

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Mon, Jan 23, 2023 at 1:59 AM 'Michal Hocko' via kernel-team wrote: > > On Fri 20-01-23 08:20:43, Suren Baghdasaryan wrote: > > On Fri, Jan 20, 2023 at 12:52 AM Michal Hocko wrote: > > > > > > On Thu 19-01-23 10:52:03, Suren Baghdasaryan wrote: > > > > On Thu, Jan 19, 2023 at 4:59 AM Michal

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Mon 23-01-23 09:07:34, Suren Baghdasaryan wrote: > On Mon, Jan 23, 2023 at 8:55 AM Michal Hocko wrote: > > > > On Mon 23-01-23 08:22:53, Suren Baghdasaryan wrote: > > > On Mon, Jan 23, 2023 at 1:56 AM Michal Hocko wrote: > > > > > > > > On Fri 20-01-23 09:50:01, Suren Baghdasaryan wrote: > >

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Mon, Jan 23, 2023 at 8:55 AM Michal Hocko wrote: > > On Mon 23-01-23 08:22:53, Suren Baghdasaryan wrote: > > On Mon, Jan 23, 2023 at 1:56 AM Michal Hocko wrote: > > > > > > On Fri 20-01-23 09:50:01, Suren Baghdasaryan wrote: > > > > On Fri, Jan 20, 2023 at 9:32 AM Matthew Wilcox > > > >

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Mon 23-01-23 08:22:53, Suren Baghdasaryan wrote: > On Mon, Jan 23, 2023 at 1:56 AM Michal Hocko wrote: > > > > On Fri 20-01-23 09:50:01, Suren Baghdasaryan wrote: > > > On Fri, Jan 20, 2023 at 9:32 AM Matthew Wilcox > > > wrote: > > [...] > > > > The page fault handler (or whatever other

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Mon, Jan 23, 2023 at 1:56 AM Michal Hocko wrote: > > On Fri 20-01-23 09:50:01, Suren Baghdasaryan wrote: > > On Fri, Jan 20, 2023 at 9:32 AM Matthew Wilcox wrote: > [...] > > > The page fault handler (or whatever other reader -- ptrace, proc, etc) > > > should have a refcount on the

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Fri 20-01-23 09:50:01, Suren Baghdasaryan wrote: > On Fri, Jan 20, 2023 at 9:32 AM Matthew Wilcox wrote: [...] > > The page fault handler (or whatever other reader -- ptrace, proc, etc) > > should have a refcount on the mm_struct, so we can't be in this path > > trying to free VMAs. Right? >

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Fri 20-01-23 08:20:43, Suren Baghdasaryan wrote: > On Fri, Jan 20, 2023 at 12:52 AM Michal Hocko wrote: > > > > On Thu 19-01-23 10:52:03, Suren Baghdasaryan wrote: > > > On Thu, Jan 19, 2023 at 4:59 AM Michal Hocko wrote: > > > > > > > > On Mon 09-01-23 12:53:34, Suren Baghdasaryan wrote: > >

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

* Suren Baghdasaryan [230120 12:50]: > On Fri, Jan 20, 2023 at 9:32 AM Matthew Wilcox wrote: > > > > On Fri, Jan 20, 2023 at 09:17:46AM -0800, Suren Baghdasaryan wrote: > > > On Fri, Jan 20, 2023 at 9:08 AM Liam R. Howlett > > > wrote: > > > > > > > > * Matthew Wilcox [230120 11:50]: > > > >

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Fri, Jan 20, 2023 at 9:21 AM Paul E. McKenney wrote: > > On Fri, Jan 20, 2023 at 04:49:42PM +, Matthew Wilcox wrote: > > On Fri, Jan 20, 2023 at 08:45:21AM -0800, Suren Baghdasaryan wrote: > > > On Fri, Jan 20, 2023 at 8:20 AM Suren Baghdasaryan > > > wrote: > > > > > > > > On Fri, Jan

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Fri, Jan 20, 2023 at 9:32 AM Matthew Wilcox wrote: > > On Fri, Jan 20, 2023 at 09:17:46AM -0800, Suren Baghdasaryan wrote: > > On Fri, Jan 20, 2023 at 9:08 AM Liam R. Howlett > > wrote: > > > > > > * Matthew Wilcox [230120 11:50]: > > > > On Fri, Jan 20, 2023 at 08:45:21AM -0800, Suren

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Fri, Jan 20, 2023 at 09:17:46AM -0800, Suren Baghdasaryan wrote: > On Fri, Jan 20, 2023 at 9:08 AM Liam R. Howlett > wrote: > > > > * Matthew Wilcox [230120 11:50]: > > > On Fri, Jan 20, 2023 at 08:45:21AM -0800, Suren Baghdasaryan wrote: > > > > On Fri, Jan 20, 2023 at 8:20 AM Suren

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Fri, Jan 20, 2023 at 04:49:42PM +, Matthew Wilcox wrote: > On Fri, Jan 20, 2023 at 08:45:21AM -0800, Suren Baghdasaryan wrote: > > On Fri, Jan 20, 2023 at 8:20 AM Suren Baghdasaryan > > wrote: > > > > > > On Fri, Jan 20, 2023 at 12:52 AM Michal Hocko wrote: > > > > > > > > On Thu

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Fri, Jan 20, 2023 at 9:08 AM Liam R. Howlett wrote: > > * Matthew Wilcox [230120 11:50]: > > On Fri, Jan 20, 2023 at 08:45:21AM -0800, Suren Baghdasaryan wrote: > > > On Fri, Jan 20, 2023 at 8:20 AM Suren Baghdasaryan > > > wrote: > > > > > > > > On Fri, Jan 20, 2023 at 12:52 AM Michal

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

* Matthew Wilcox [230120 11:50]: > On Fri, Jan 20, 2023 at 08:45:21AM -0800, Suren Baghdasaryan wrote: > > On Fri, Jan 20, 2023 at 8:20 AM Suren Baghdasaryan > > wrote: > > > > > > On Fri, Jan 20, 2023 at 12:52 AM Michal Hocko wrote: > > > > > > > > On Thu 19-01-23 10:52:03, Suren Baghdasaryan

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Fri, Jan 20, 2023 at 08:45:21AM -0800, Suren Baghdasaryan wrote: > On Fri, Jan 20, 2023 at 8:20 AM Suren Baghdasaryan wrote: > > > > On Fri, Jan 20, 2023 at 12:52 AM Michal Hocko wrote: > > > > > > On Thu 19-01-23 10:52:03, Suren Baghdasaryan wrote: > > > > On Thu, Jan 19, 2023 at 4:59 AM

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Fri, Jan 20, 2023 at 8:20 AM Suren Baghdasaryan wrote: > > On Fri, Jan 20, 2023 at 12:52 AM Michal Hocko wrote: > > > > On Thu 19-01-23 10:52:03, Suren Baghdasaryan wrote: > > > On Thu, Jan 19, 2023 at 4:59 AM Michal Hocko wrote: > > > > > > > > On Mon 09-01-23 12:53:34, Suren Baghdasaryan

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Fri, Jan 20, 2023 at 12:52 AM Michal Hocko wrote: > > On Thu 19-01-23 10:52:03, Suren Baghdasaryan wrote: > > On Thu, Jan 19, 2023 at 4:59 AM Michal Hocko wrote: > > > > > > On Mon 09-01-23 12:53:34, Suren Baghdasaryan wrote: > > > > call_rcu() can take a long time when callback offloading is

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Fri, Jan 20, 2023 at 09:57:05AM +0100, Michal Hocko wrote: > On Thu 19-01-23 11:17:07, Paul E. McKenney wrote: > > On Thu, Jan 19, 2023 at 01:52:14PM +0100, Michal Hocko wrote: > > > On Wed 18-01-23 11:01:08, Suren Baghdasaryan wrote: > > > > On Wed, Jan 18, 2023 at 10:34 AM Paul E. McKenney

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Thu 19-01-23 11:17:07, Paul E. McKenney wrote: > On Thu, Jan 19, 2023 at 01:52:14PM +0100, Michal Hocko wrote: > > On Wed 18-01-23 11:01:08, Suren Baghdasaryan wrote: > > > On Wed, Jan 18, 2023 at 10:34 AM Paul E. McKenney > > > wrote: > > [...] > > > > There are a couple of possibilities

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Thu 19-01-23 10:52:03, Suren Baghdasaryan wrote: > On Thu, Jan 19, 2023 at 4:59 AM Michal Hocko wrote: > > > > On Mon 09-01-23 12:53:34, Suren Baghdasaryan wrote: > > > call_rcu() can take a long time when callback offloading is enabled. > > > Its use in the vm_area_free can cause regressions

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Thu, Jan 19, 2023 at 11:47:36AM -0800, Suren Baghdasaryan wrote: > On Thu, Jan 19, 2023 at 11:20 AM Paul E. McKenney wrote: > > > > On Thu, Jan 19, 2023 at 10:52:03AM -0800, Suren Baghdasaryan wrote: > > > On Thu, Jan 19, 2023 at 4:59 AM Michal Hocko wrote: > > > > > > > > On Mon 09-01-23

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Thu, Jan 19, 2023 at 11:20 AM Paul E. McKenney wrote: > > On Thu, Jan 19, 2023 at 10:52:03AM -0800, Suren Baghdasaryan wrote: > > On Thu, Jan 19, 2023 at 4:59 AM Michal Hocko wrote: > > > > > > On Mon 09-01-23 12:53:34, Suren Baghdasaryan wrote: > > > > call_rcu() can take a long time when

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Thu, Jan 19, 2023 at 10:52:03AM -0800, Suren Baghdasaryan wrote: > On Thu, Jan 19, 2023 at 4:59 AM Michal Hocko wrote: > > > > On Mon 09-01-23 12:53:34, Suren Baghdasaryan wrote: > > > call_rcu() can take a long time when callback offloading is enabled. > > > Its use in the vm_area_free can

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Thu, Jan 19, 2023 at 01:52:14PM +0100, Michal Hocko wrote: > On Wed 18-01-23 11:01:08, Suren Baghdasaryan wrote: > > On Wed, Jan 18, 2023 at 10:34 AM Paul E. McKenney > > wrote: > [...] > > > There are a couple of possibilities here. > > > > > > First, if I am remembering correctly, the time

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Thu, Jan 19, 2023 at 4:59 AM Michal Hocko wrote: > > On Mon 09-01-23 12:53:34, Suren Baghdasaryan wrote: > > call_rcu() can take a long time when callback offloading is enabled. > > Its use in the vm_area_free can cause regressions in the exit path when > > multiple VMAs are being freed. To

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Mon 09-01-23 12:53:34, Suren Baghdasaryan wrote: > call_rcu() can take a long time when callback offloading is enabled. > Its use in the vm_area_free can cause regressions in the exit path when > multiple VMAs are being freed. To minimize that impact, place VMAs into > a list and free them in

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Wed 18-01-23 11:01:08, Suren Baghdasaryan wrote: > On Wed, Jan 18, 2023 at 10:34 AM Paul E. McKenney wrote: [...] > > There are a couple of possibilities here. > > > > First, if I am remembering correctly, the time between the call_rcu() > > and invocation of the corresponding callback was

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Wed, Jan 18, 2023 at 11:01:08AM -0800, Suren Baghdasaryan wrote: > On Wed, Jan 18, 2023 at 10:34 AM Paul E. McKenney wrote: > > > > On Wed, Jan 18, 2023 at 10:04:39AM -0800, Suren Baghdasaryan wrote: > > > On Wed, Jan 18, 2023 at 1:49 AM Michal Hocko wrote: > > > > > > > > On Tue 17-01-23

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Wed, Jan 18, 2023 at 10:34 AM Paul E. McKenney wrote: > > On Wed, Jan 18, 2023 at 10:04:39AM -0800, Suren Baghdasaryan wrote: > > On Wed, Jan 18, 2023 at 1:49 AM Michal Hocko wrote: > > > > > > On Tue 17-01-23 17:19:46, Suren Baghdasaryan wrote: > > > > On Tue, Jan 17, 2023 at 7:57 AM Michal

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Wed, Jan 18, 2023 at 10:04:39AM -0800, Suren Baghdasaryan wrote: > On Wed, Jan 18, 2023 at 1:49 AM Michal Hocko wrote: > > > > On Tue 17-01-23 17:19:46, Suren Baghdasaryan wrote: > > > On Tue, Jan 17, 2023 at 7:57 AM Michal Hocko wrote: > > > > > > > > On Mon 09-01-23 12:53:34, Suren

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Wed, Jan 18, 2023 at 1:49 AM Michal Hocko wrote: > > On Tue 17-01-23 17:19:46, Suren Baghdasaryan wrote: > > On Tue, Jan 17, 2023 at 7:57 AM Michal Hocko wrote: > > > > > > On Mon 09-01-23 12:53:34, Suren Baghdasaryan wrote: > > > > call_rcu() can take a long time when callback offloading is

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Tue 17-01-23 17:19:46, Suren Baghdasaryan wrote: > On Tue, Jan 17, 2023 at 7:57 AM Michal Hocko wrote: > > > > On Mon 09-01-23 12:53:34, Suren Baghdasaryan wrote: > > > call_rcu() can take a long time when callback offloading is enabled. > > > Its use in the vm_area_free can cause regressions

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Tue, Jan 17, 2023 at 7:57 AM Michal Hocko wrote: > > On Mon 09-01-23 12:53:34, Suren Baghdasaryan wrote: > > call_rcu() can take a long time when callback offloading is enabled. > > Its use in the vm_area_free can cause regressions in the exit path when > > multiple VMAs are being freed. > >

Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

On Mon 09-01-23 12:53:34, Suren Baghdasaryan wrote: > call_rcu() can take a long time when callback offloading is enabled. > Its use in the vm_area_free can cause regressions in the exit path when > multiple VMAs are being freed. What kind of regressions. > To minimize that impact, place VMAs

[PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free

call_rcu() can take a long time when callback offloading is enabled. Its use in the vm_area_free can cause regressions in the exit path when multiple VMAs are being freed. To minimize that impact, place VMAs into a list and free them in groups using one call_rcu() call per group. Signed-off-by: