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From: Christian Brauner <christian.brauner@ubuntu.com>
To: Mike Christie <michael.christie@oracle.com>
Cc: hdanton@sina.com, hch@infradead.org, stefanha@redhat.com,
	jasowang@redhat.com, mst@redhat.com, sgarzare@redhat.com,
	virtualization@lists.linux-foundation.org, axboe@kernel.dk,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH V2 4/9] fork: add option to not clone or dup files
Date: Wed, 22 Sep 2021 14:46:34 +0200	[thread overview]
Message-ID: <20210922124634.zodjcbvksdkhjrym@wittgenstein> (raw)
In-Reply-To: <20210921215218.89844-5-michael.christie@oracle.com>

On Tue, Sep 21, 2021 at 04:52:13PM -0500, Mike Christie wrote:
> Each vhost device gets a thread that is used to perform IO and management
> operations. Instead of a thread that is accessing a device, the thread is
> part of the device, so when it calls the kernel_worker() function added in
> the next patch we can't dup or clone the parent's files/FDS because it would
> do an extra increment on ourself.
> 
> Later, when we do:
> 
> Qemu process exits:
>         do_exit -> exit_files -> put_files_struct -> close_files
> 
> we would leak the device's resources because of that extra refcount
> on the fd or file_struct.
> 
> This patch adds a no_files option so these worker threads can prevent
> taking an extra refcount on themselves.
> 
> Signed-off-by: Mike Christie <michael.christie@oracle.com>

Ok,
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>

  reply	other threads:[~2021-09-22 12:46 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-21 21:52 [PATCH V2 0/9] Use copy_process/create_io_thread in vhost layer Mike Christie
2021-09-21 21:52 ` [PATCH V2 1/9] fork: Make IO worker options flag based Mike Christie
2021-09-22 12:44   ` Christian Brauner
2021-09-21 21:52 ` [PATCH V2 2/9] fork: pass worker_flags to copy_thread Mike Christie
2021-09-22 12:42   ` Christian Brauner
2021-09-22 14:18   ` Geert Uytterhoeven
2021-09-21 21:52 ` [PATCH V2 3/9] fork: move PF_IO_WORKER's kernel frame setup to new flag Mike Christie
2021-09-22 12:32   ` Geert Uytterhoeven
2021-09-22 12:39     ` Christian Brauner
2021-09-22 12:45     ` Christian Brauner
2021-09-21 21:52 ` [PATCH V2 4/9] fork: add option to not clone or dup files Mike Christie
2021-09-22 12:46   ` Christian Brauner [this message]
2021-09-21 21:52 ` [PATCH V2 5/9] fork: add helper to clone a process Mike Christie
2021-09-22 12:50   ` Christian Brauner
2021-09-21 21:52 ` [PATCH V2 6/9] io_uring: switch to kernel_worker Mike Christie
2021-09-22 12:53   ` Christian Brauner
2021-09-21 21:52 ` [PATCH V2 7/9] fork: Add worker flag to ignore signals Mike Christie
2021-09-22 12:52   ` Christian Brauner
2021-09-21 21:52 ` [PATCH V2 8/9] vhost: move worker thread fields to new struct Mike Christie
2021-10-04 13:12   ` Michael S. Tsirkin
2021-09-21 21:52 ` [PATCH V2 9/9] vhost: use kernel_worker to check RLIMITs and inherit v2 cgroups Mike Christie
2021-10-04 13:12   ` Michael S. Tsirkin

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