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From: Hugh Dickins <hughd@google.com>
To: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Hugh Dickins <hughd@google.com>,
	"Alex Xu (Hello71)" <alex_y_xu@yahoo.ca>,
	Vineeth Pillai <vpillai@digitalocean.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Kelley Nielsen <kelleynnn@gmail.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Rik van Riel <riel@surriel.com>,
	Huang Ying <ying.huang@intel.com>,
	Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: shmem_recalc_inode: unable to handle kernel NULL pointer dereference
Date: Mon, 8 Apr 2019 10:26:17 -0700 (PDT)
Message-ID: <alpine.LSU.2.11.1904081014060.2770@eggly.anvils> (raw)
In-Reply-To: <1b0bc97a-8162-d4df-7187-7636e5934b23@yandex-team.ru>

On Mon, 8 Apr 2019, Konstantin Khlebnikov wrote:
> 
> I suppose your solution will wait for wakeup from shmem_evict_inode()?

No, it's the other way round: shmem_unuse() gets on with its work without
delay, shmem_evict_inode() waits until the stop_eviction count has gone
down to zero, saying nobody else is at work on the inode.

Waiting in shmem_evict_inode() might be more worrying, if it weren't
already packed full with lock_page()s. And less attractive with the old
quadratic style of swapoff, when shmem_evict_inode() would have freed
the inode's swap much more efficiently than swapoff could then manage.

Hugh

      reply index

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-24 15:30 Alex Xu (Hello71)
2019-03-25 22:08 ` Vineeth Pillai
2019-03-31 16:15   ` Alex Xu (Hello71)
2019-03-31 19:21     ` Hugh Dickins
2019-04-03  0:30       ` Hugh Dickins
2019-04-05  2:12         ` Hugh Dickins
2019-04-05  9:41           ` Konstantin Khlebnikov
2019-04-08  6:05             ` Hugh Dickins
2019-04-08  7:19               ` Konstantin Khlebnikov
2019-04-08 17:26                 ` Hugh Dickins [this message]

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