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?
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: linux-arch@vger.kernel.org, Randy Dunlap <rdunlap@infradead.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Andy Lutomirski <luto@kernel.org>,
linuxppc-dev@lists.ozlabs.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: 48+ 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 ` Nicholas Piggin
2021-06-05 1:42 ` [PATCH v4 1/4] lazy tlb: introduce lazy mm refcount helper functions Nicholas Piggin
2021-06-05 1:42 ` Nicholas Piggin
2021-06-07 23:49 ` Andrew Morton [this message]
2021-06-07 23:49 ` Andrew Morton
2021-06-08 1:39 ` Nicholas Piggin
2021-06-08 1:39 ` Nicholas Piggin
2021-06-08 1:48 ` Andrew Morton
2021-06-08 1:48 ` Andrew Morton
2021-06-08 4:11 ` Nicholas Piggin
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
2021-06-05 1:42 ` Nicholas Piggin
2021-06-08 3:11 ` Nicholas Piggin
2021-06-08 3:11 ` Nicholas Piggin
2021-06-08 16:20 ` Andy Lutomirski
2021-06-08 16:20 ` Andy Lutomirski
2021-06-14 0:45 ` Nicholas Piggin
2021-06-14 0:45 ` Nicholas Piggin
2021-06-14 3:52 ` Andy Lutomirski
2021-06-14 3:52 ` Andy Lutomirski
2021-06-14 4:14 ` Nicholas Piggin
2021-06-14 4:14 ` Nicholas Piggin
2021-06-14 4:47 ` Nicholas Piggin
2021-06-14 4:47 ` Nicholas Piggin
2021-06-14 5:21 ` Nicholas Piggin
2021-06-14 5:21 ` Nicholas Piggin
2021-06-14 16:20 ` Andy Lutomirski
2021-06-14 16:20 ` Andy Lutomirski
2021-06-15 0:55 ` Nicholas Piggin
2021-06-15 0:55 ` Nicholas Piggin
2021-06-16 0:14 ` Andy Lutomirski
2021-06-16 0:14 ` Andy Lutomirski
2021-06-16 1:02 ` Nicholas Piggin
2021-06-16 1:02 ` Nicholas Piggin
2021-06-17 0:32 ` 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
2021-06-05 1:42 ` Nicholas Piggin
2021-06-08 3:15 ` 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
2021-06-05 1:42 ` Nicholas Piggin
2021-06-07 23:52 ` Andrew Morton
2021-06-07 23:52 ` Andrew Morton
2021-06-08 2:13 ` Nicholas Piggin
2021-06-08 2:13 ` Nicholas Piggin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210607164934.d453adcc42473e84beb25db3@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=anton@ozlabs.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=luto@kernel.org \
--cc=npiggin@gmail.com \
--cc=rdunlap@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.