From: Andrew Morton <akpm@linux-foundation.org>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org,
Anton Blanchard <anton@ozlabs.org>,
Andy Lutomirski <luto@kernel.org>
Subject: Re: [PATCH v4 1/4] lazy tlb: introduce lazy mm refcount helper functions
Date: Mon, 7 Jun 2021 16:49:34 -0700 [thread overview]
Message-ID: <20210607164934.d453adcc42473e84beb25db3@linux-foundation.org> (raw)
In-Reply-To: <20210605014216.446867-2-npiggin@gmail.com>
On Sat, 5 Jun 2021 11:42:13 +1000 Nicholas Piggin <npiggin@gmail.com> wrote:
> Add explicit _lazy_tlb annotated functions for lazy mm refcounting.
> This makes lazy mm references more obvious, and allows explicit
> refcounting to be removed if it is not used.
>
> ...
>
> --- a/kernel/kthread.c
> +++ b/kernel/kthread.c
> @@ -1314,14 +1314,14 @@ void kthread_use_mm(struct mm_struct *mm)
> WARN_ON_ONCE(!(tsk->flags & PF_KTHREAD));
> WARN_ON_ONCE(tsk->mm);
>
> + mmgrab(mm);
> +
> task_lock(tsk);
> /* Hold off tlb flush IPIs while switching mm's */
> local_irq_disable();
> active_mm = tsk->active_mm;
> - if (active_mm != mm) {
> - mmgrab(mm);
> + if (active_mm != mm)
> tsk->active_mm = mm;
> - }
Looks like a functional change. What's happening here?
next prev parent reply other threads:[~2021-06-07 23:49 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-05 1:42 [PATCH v4 0/4] shoot lazy tlbs Nicholas Piggin
2021-06-05 1:42 ` [PATCH v4 1/4] lazy tlb: introduce lazy mm refcount helper functions Nicholas Piggin
2021-06-07 23:49 ` Andrew Morton [this message]
2021-06-08 1:39 ` Nicholas Piggin
2021-06-08 1:48 ` Andrew Morton
2021-06-08 4:11 ` Nicholas Piggin
2021-06-05 1:42 ` [PATCH v4 2/4] lazy tlb: allow lazy tlb mm refcounting to be configurable Nicholas Piggin
2021-06-08 3:11 ` Nicholas Piggin
2021-06-08 16:20 ` Andy Lutomirski
2021-06-14 0:45 ` Nicholas Piggin
2021-06-14 3:52 ` Andy Lutomirski
2021-06-14 4:14 ` Nicholas Piggin
2021-06-14 4:47 ` Nicholas Piggin
2021-06-14 5:21 ` Nicholas Piggin
2021-06-14 16:20 ` Andy Lutomirski
2021-06-15 0:55 ` Nicholas Piggin
2021-06-16 0:14 ` Andy Lutomirski
2021-06-16 1:02 ` Nicholas Piggin
2021-06-17 0:32 ` Nicholas Piggin
2021-06-05 1:42 ` [PATCH v4 3/4] lazy tlb: shoot lazies, a non-refcounting lazy tlb option Nicholas Piggin
2021-06-08 3:15 ` Nicholas Piggin
2021-06-05 1:42 ` [PATCH v4 4/4] powerpc/64s: enable MMU_LAZY_TLB_SHOOTDOWN Nicholas Piggin
2021-06-07 23:52 ` Andrew Morton
2021-06-08 2:13 ` Nicholas Piggin
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