lkml.org 
[lkml]   [2021]   [Feb]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 2/2] rcu-tasks: add RCU-tasks self tests
    On Wed, 17 Feb 2021 10:17:38 -0800
    "Paul E. McKenney" <paulmck@kernel.org> wrote:

    > > > 1. Spawn ksoftirqd earlier.
    > > >
    > > > 2. Suppress attempts to awaken ksoftirqd before it exists,
    > > > forcing all ksoftirq execution on the back of interrupts.
    > > >
    > > > Uladzislau and I each produced patches for #1, and I produced a patch
    > > > for #2.
    > > >
    > > > The only other option I know of is to push the call to init_kprobes()
    > > > later in the boot sequence, perhaps to its original subsys_initcall(),
    > > > or maybe only as late as core_initcall(). I added Masami and Steve on
    > > > CC for their thoughts on this.
    > > >
    > > > Is there some other proper fix that I am missing?
    > >
    > > Oh, I missed that the synchronize_rcu_tasks() will be involved the kprobes
    > > in early stage. Does the problem only exist in the synchronize_rcu_tasks()
    > > instead of synchronize_rcu()? If so I can just stop optimizer in early stage
    > > because I just want to enable kprobes in early stage, but not optprobes.
    > >
    > > Does the following patch help?
    >
    > It does look to me like it would! I clearly should have asked you about
    > this a couple of months ago. ;-)
    >
    > The proof of the pudding would be whether the powerpc guys can apply
    > this to v5.10-rc7 and have their kernel come up without hanging at boot.

    Who could I ask for testing this patch, Uladzislau?
    I think the test machine which enough slow or the kernel has much initcall
    to run optimization thread while booting.
    In my environment, I could not reproduce that issue because the optimizer
    was sheduled after some tick passed. At that point, ksoftirqd has already
    been initialized.

    Thank you,


    --
    Masami Hiramatsu <mhiramat@kernel.org>

    \
     
     \ /
      Last update: 2021-02-18 06:05    [W:4.057 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site