lkml.org 
[lkml]   [2013]   [Nov]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 1/2] sched/mm: add finish_switch_mm function
    On Wed, Nov 13, 2013 at 09:16:13AM +0100, Martin Schwidefsky wrote:
    > The switch_mm function is called with the task_lock and/or with
    > request queue lock. Add finish_switch_mm to allow an architecture
    > to execute some code after the mm has been switched but without
    > any locks held. One use case is the s390 architecture which will
    > use this to wait for the completion of TLB flush operations.

    This so reminds me of what finish_arch_post_lock_switch() was supposed
    to do. See commit: 01f23e1630d9 ("sched/arch: Introduce the
    finish_arch_post_lock_switch() scheduler callback").

    Now you hook into more places; but maybe you can Catalin can come up
    with something you both can use?

    (preserved patch for Catalin)

    > Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
    > ---
    > include/linux/mmu_context.h | 6 ++++++
    > kernel/sched/core.c | 7 +++++--
    > mm/mmu_context.c | 3 +--
    > 3 files changed, 12 insertions(+), 4 deletions(-)
    >
    > diff --git a/include/linux/mmu_context.h b/include/linux/mmu_context.h
    > index 70fffeb..0971c37 100644
    > --- a/include/linux/mmu_context.h
    > +++ b/include/linux/mmu_context.h
    > @@ -1,9 +1,15 @@
    > #ifndef _LINUX_MMU_CONTEXT_H
    > #define _LINUX_MMU_CONTEXT_H
    >
    > +#include <asm/mmu_context.h>
    > +
    > struct mm_struct;
    >
    > void use_mm(struct mm_struct *mm);
    > void unuse_mm(struct mm_struct *mm);
    >
    > +#ifndef finish_switch_mm
    > +#define finish_switch_mm(mm, tsk) do { } while (0)
    > +#endif
    > +
    > #endif
    > diff --git a/kernel/sched/core.c b/kernel/sched/core.c
    > index 1deccd7..89409cb 100644
    > --- a/kernel/sched/core.c
    > +++ b/kernel/sched/core.c
    > @@ -32,7 +32,7 @@
    > #include <linux/init.h>
    > #include <linux/uaccess.h>
    > #include <linux/highmem.h>
    > -#include <asm/mmu_context.h>
    > +#include <linux/mmu_context.h>
    > #include <linux/interrupt.h>
    > #include <linux/capability.h>
    > #include <linux/completion.h>
    > @@ -1996,6 +1996,7 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
    > perf_event_task_sched_in(prev, current);
    > finish_lock_switch(rq, prev);
    > finish_arch_post_lock_switch();
    > + finish_switch_mm(current->mm, current);
    >
    > fire_sched_in_preempt_notifiers(current);
    > if (mm)
    > @@ -4140,8 +4141,10 @@ void idle_task_exit(void)
    >
    > BUG_ON(cpu_online(smp_processor_id()));
    >
    > - if (mm != &init_mm)
    > + if (mm != &init_mm) {
    > switch_mm(mm, &init_mm, current);
    > + finish_switch_mm(&init_mm, current);
    > + }
    > mmdrop(mm);
    > }
    >
    > diff --git a/mm/mmu_context.c b/mm/mmu_context.c
    > index 8a8cd02..11b3d47 100644
    > --- a/mm/mmu_context.c
    > +++ b/mm/mmu_context.c
    > @@ -8,8 +8,6 @@
    > #include <linux/export.h>
    > #include <linux/sched.h>
    >
    > -#include <asm/mmu_context.h>
    > -
    > /*
    > * use_mm
    > * Makes the calling kernel thread take on the specified
    > @@ -31,6 +29,7 @@ void use_mm(struct mm_struct *mm)
    > tsk->mm = mm;
    > switch_mm(active_mm, mm, tsk);
    > task_unlock(tsk);
    > + finish_switch_mm(mm, tsk);
    >
    > if (active_mm != mm)
    > mmdrop(active_mm);
    > --
    > 1.7.9.5
    >


    \
     
     \ /
      Last update: 2013-11-13 13:01    [W:6.186 / U:0.608 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site