From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Jan Kara <jack@suse.cz>
Cc: linux-ext4@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Anna-Maria Gleixner <anna-maria@linutronix.de>,
Julia Cartwright <julia@ni.com>
Subject: Re: [PATCH 0/7 v2] jbd2: Bit spinlock conversions
Date: Sun, 3 Nov 2019 14:01:41 -0500 [thread overview]
Message-ID: <20191103190141.GA8037@mit.edu> (raw)
In-Reply-To: <20190809124233.13277-1-jack@suse.cz>
On Fri, Aug 09, 2019 at 02:42:26PM +0200, Jan Kara wrote:
> Hello,
>
> This series is derived from Thomas' series to get rid of bit spinlocks in
> buffer head code. These patches convert BH_State bit spinlock to an ordinary
> spinlock inside struct journal_head and somewhat reduce the critical section
> under BH_JournalHead bit spinlock so that it is fine for RT.
>
> Motivation from original Thomas' series:
>
> Bit spinlocks are problematic if PREEMPT_RT is enabled. They disable
> preemption, which is undesired for latency reasons and breaks when regular
> spinlocks are taken within the bit_spinlock locked region because regular
> spinlocks are converted to 'sleeping spinlocks' on RT.
>
> Bit spinlocks are also not covered by lock debugging, e.g. lockdep. With
> the spinlock substitution in place, they can be exposed via a new config
> switch: CONFIG_DEBUG_BIT_SPINLOCKS.
>
> Ted, can you pick up these patches? Thanks!
I've landed this patch set on the ext4 git tree. Thanks!
- Ted
prev parent reply other threads:[~2019-11-03 19:02 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-09 12:42 [PATCH 0/7 v2] jbd2: Bit spinlock conversions Jan Kara
2019-08-09 12:42 ` [PATCH 1/7] jbd2: Simplify journal_unmap_buffer() Jan Kara
2019-08-09 12:42 ` [PATCH 2/7] jbd2: Remove jbd_trylock_bh_state() Jan Kara
2019-08-09 12:42 ` [PATCH 3/7] jbd2: Move dropping of jh reference out of un/re-filing functions Jan Kara
2019-08-09 12:42 ` [PATCH 4/7] jbd2: Drop unnecessary branch from jbd2_journal_forget() Jan Kara
2019-08-09 12:42 ` [PATCH 5/7] jbd2: Don't call __bforget() unnecessarily Jan Kara
2019-10-28 15:28 ` Theodore Y. Ts'o
2019-10-28 16:01 ` Theodore Y. Ts'o
2019-10-30 11:49 ` Jan Kara
2019-08-09 12:42 ` [PATCH 6/7] jbd2: Make state lock a spinlock Jan Kara
2019-08-09 12:42 ` [PATCH 7/7] jbd2: Free journal head outside of locked region Jan Kara
2019-10-11 12:31 ` [PATCH 0/7 v2] jbd2: Bit spinlock conversions Sebastian Andrzej Siewior
2019-11-03 19:01 ` Theodore Y. Ts'o [this message]
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