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From: peterz@infradead.org
To: Matthew Wilcox <willy@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>,
	Boaz Harrosh <boaz@plexistor.com>, Hou Tao <houtao1@huawei.com>,
	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 15:22:30 +0200	[thread overview]
Message-ID: <20200917132230.GG1362448@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200917124838.GT5449@casper.infradead.org>

On Thu, Sep 17, 2020 at 01:48:38PM +0100, Matthew Wilcox wrote:
> On Thu, Sep 17, 2020 at 02:01:33PM +0200, Oleg Nesterov wrote:
> > IIUC, file_end_write() was never IRQ safe (at least if !CONFIG_SMP), even
> > before 8129ed2964 ("change sb_writers to use percpu_rw_semaphore"), but this
> > doesn't matter...
> > 
> > Perhaps we can change aio.c, io_uring.c and fs/overlayfs/file.c to avoid
> > file_end_write() in IRQ context, but I am not sure it's worth the trouble.
> 
> 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

SoftIRQ context has exactly the same problem vs __this_cpu*().

  reply	other threads:[~2020-09-17 13:36 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-15 14:07 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 [this message]
2020-09-17 13:34                 ` Oleg Nesterov
2020-09-17 13:46                 ` Boaz Harrosh
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

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