Messages in this thread | | | Date | Mon, 25 Apr 2022 13:29:04 -0300 | From | Marcelo Tosatti <> | Subject | Re: [patch v12 00/13] extensible prctl task isolation interface and vmstat sync |
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On Thu, Mar 17, 2022 at 04:08:04PM +0100, Frederic Weisbecker wrote: > On Tue, Mar 15, 2022 at 12:31:32PM -0300, Marcelo Tosatti wrote: > > The logic to disable vmstat worker thread, when entering > > nohz full, does not cover all scenarios. For example, it is possible > > for the following to happen: > > > > 1) enter nohz_full, which calls refresh_cpu_vm_stats, syncing the stats. > > 2) app runs mlock, which increases counters for mlock'ed pages. > > 3) start -RT loop > > > > Since refresh_cpu_vm_stats from nohz_full logic can happen _before_ > > the mlock, vmstat shepherd can restart vmstat worker thread on > > the CPU in question. > > > > To fix this, add task isolation prctl interface to quiesce > > deferred actions when returning to userspace. > > > > The patchset is based on ideas and code from the > > task isolation patchset from Alex Belits: > > https://lwn.net/Articles/816298/ > > > > Please refer to Documentation/userspace-api/task_isolation.rst > > (patch 1) for details. Its attached at the end of this message > > in .txt format as well. > > > > Note: the prctl interface is independent of nohz_full=. > > > > The userspace patches can be found at https://people.redhat.com/~mtosatti/task-isol-v6-userspace-patches/ > > > > - qemu-task-isolation.patch: activate task isolation from CPU execution loop > > - rt-tests-task-isolation.patch: add task isolation activation to cyclictest/oslat > > - util-linux-chisol.patch: add chisol tool to util-linux. > > I still see a few details to sort out but overall the whole thing looks good: > > Acked-by: Frederic Weisbecker <fweisbec@gmail.com> > > Perhaps it's time to apply this patchset on some branch and iterate from there. > > Thomas, Peter, what do you think? > > Thanks!
Ping ?
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