From: Boaz Harrosh <boaz@plexistor.com>
To: Matthew Wilcox <willy@infradead.org>, Oleg Nesterov <oleg@redhat.com>
Cc: Hou Tao <houtao1@huawei.com>,
peterz@infradead.org, Ingo Molnar <mingo@redhat.com>,
Will Deacon <will@kernel.org>, Dennis Zhou <dennis@kernel.org>,
Tejun Heo <tj@kernel.org>, Christoph Lameter <cl@linux.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Jan Kara <jack@suse.cz>
Subject: Re: [RFC PATCH] locking/percpu-rwsem: use this_cpu_{inc|dec}() for read_count
Date: Thu, 17 Sep 2020 16:46:38 +0300 [thread overview]
Message-ID: <e25a3354-04e4-54e9-a45f-7305bfd1f2bb@plexistor.com> (raw)
In-Reply-To: <20200917124838.GT5449@casper.infradead.org>
On 17/09/2020 15:48, Matthew Wilcox wrote:
> On Thu, Sep 17, 2020 at 02:01:33PM +0200, Oleg Nesterov wrote:
<>
>
> If we change bio_endio to invoke the ->bi_end_io callbacks in softirq
> context instead of hardirq context, we can change the pagecache to take
> BH-safe locks instead of IRQ-safe locks. I believe the only reason the
> lock needs to be IRQ-safe is for the benefit of paths like:
>
From my totally subjective experience on the filesystem side (user of
bio_endio) all HW block drivers I used including Nvme isci, sata... etc.
end up calling bio_endio in softirq. The big exception to that is the
vdX drivers under KVM. Which is very Ironic to me.
I wish we could make all drivers be uniform in this regard.
But maybe I'm just speaking crap. Its only from my limited debuging
expirience.
Thanks
Boaz
next prev parent reply other threads:[~2020-09-17 13:54 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-15 14:07 [RFC PATCH] locking/percpu-rwsem: use this_cpu_{inc|dec}() for read_count Hou Tao
2020-09-15 15:06 ` peterz
2020-09-15 15:31 ` Oleg Nesterov
2020-09-15 15:51 ` peterz
2020-09-15 16:03 ` peterz
2020-09-15 16:11 ` Will Deacon
2020-09-15 18:11 ` peterz
2020-09-16 8:20 ` Will Deacon
2020-09-15 16:47 ` Oleg Nesterov
2020-09-16 12:32 ` Hou Tao
2020-09-16 12:51 ` peterz
2020-09-17 8:48 ` Will Deacon
2020-09-24 11:55 ` Hou Tao
2020-09-29 17:49 ` Will Deacon
2020-09-29 18:07 ` Ard Biesheuvel
2020-09-17 10:51 ` Boaz Harrosh
2020-09-17 12:01 ` Oleg Nesterov
2020-09-17 12:48 ` Matthew Wilcox
2020-09-17 13:22 ` peterz
2020-09-17 13:34 ` Oleg Nesterov
2020-09-17 13:46 ` Boaz Harrosh [this message]
2020-09-17 14:46 ` Christoph Hellwig
2020-09-18 9:07 ` Jan Kara
2020-09-18 10:01 ` peterz
2020-09-18 10:04 ` peterz
2020-09-18 10:07 ` peterz
2020-09-18 10:12 ` peterz
2020-09-18 10:48 ` Oleg Nesterov
2020-09-18 11:03 ` peterz
2020-09-18 13:09 ` Oleg Nesterov
2020-09-18 13:26 ` Jan Kara
2020-09-20 23:49 ` Dave Chinner
2020-09-18 8:36 ` [tip: locking/urgent] locking/percpu-rwsem: Use this_cpu_{inc,dec}() " tip-bot2 for Hou Tao
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