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From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>, Nitin Gupta <ngupta@vflare.org>,
	Jerome Marchand <jmarchan@redhat.com>,
	Ganesh Mahendran <opensource.ganesh@gmail.com>
Subject: Re: [PATCH v1 2/2] zram: remove init_lock in zram_make_request
Date: Mon, 2 Feb 2015 10:59:40 +0900	[thread overview]
Message-ID: <20150202015940.GB6977@swordfish> (raw)
In-Reply-To: <20150202014315.GC6402@blaptop>

On (02/02/15 10:43), Minchan Kim wrote:
> >  static inline int init_done(struct zram *zram)
> >  {
> > -	return zram->meta != NULL;
> > +	return atomic_read(&zram->refcount);
> 
> As I said previous mail, it could make livelock so I want to use disksize
> in here to prevent further I/O handling.

just as I said in my previous email -- is this live lock really possible?
we need to umount device to continue with reset. and umount will kill IOs out
of our way.

the other reset caller is  __exit zram_exit(). but once again, I don't
expect this function being executed on mounted device and module being
in use.


> > +static inline void zram_put(struct zram *zram)
> > +{
> > +	if (atomic_dec_and_test(&zram->refcount))
> > +		complete(&zram->io_done);
> > +}
> 
> Although I suggested this complete, it might be rather overkill(pz,
> understand me it was work in midnight. :))
> Instead, we could use just atomic_dec in here and
> use wait_event(event, atomic_read(&zram->refcount) == 0) in reset.
> 

yes, I think it can do the trick.

	-ss

  reply	other threads:[~2015-02-02  1:59 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1422432945-6764-1-git-send-email-minchan@kernel.org>
2015-01-28 14:19 ` [PATCH 1/2] zram: free meta table in zram_meta_free Sergey Senozhatsky
2015-01-28 23:17   ` Minchan Kim
2015-01-29  1:49     ` Ganesh Mahendran
     [not found] ` <1422432945-6764-2-git-send-email-minchan@kernel.org>
2015-01-28 14:56   ` [PATCH v1 2/2] zram: remove init_lock in zram_make_request Sergey Senozhatsky
2015-01-28 15:04     ` Sergey Senozhatsky
2015-01-28 23:33     ` Minchan Kim
     [not found]       ` <CAHqPoqKZFDSjO1pL+ixYe_m_L0nGNcu04qSNp-jd1fUixKtHnw@mail.gmail.com>
2015-01-29  2:01         ` Minchan Kim
2015-01-29  2:22           ` Sergey Senozhatsky
2015-01-29  5:28             ` Minchan Kim
2015-01-29  6:06               ` Sergey Senozhatsky
2015-01-29  6:35                 ` Minchan Kim
2015-01-29  7:08                   ` Sergey Senozhatsky
2015-01-30 14:41                     ` Minchan Kim
2015-01-31 11:31                       ` Sergey Senozhatsky
2015-02-01 14:50                       ` Sergey Senozhatsky
2015-02-01 15:04                         ` Sergey Senozhatsky
2015-02-02  1:43                           ` Minchan Kim
2015-02-02  1:59                             ` Sergey Senozhatsky [this message]
2015-02-02  2:45                               ` Minchan Kim
2015-02-02  3:47                                 ` Sergey Senozhatsky
2015-02-02  1:30                         ` Minchan Kim
2015-02-02  1:48                           ` Sergey Senozhatsky
2015-02-02  2:44                             ` Minchan Kim
2015-02-02  4:01                               ` Sergey Senozhatsky
2015-02-02  4:28                                 ` Minchan Kim
2015-02-02  5:09                                   ` Sergey Senozhatsky
2015-02-02  5:18                                     ` Minchan Kim
2015-02-02  5:28                                       ` Sergey Senozhatsky
2015-02-02  5:10                                   ` Minchan Kim
2015-01-30  0:20                   ` Sergey Senozhatsky
2015-01-29 13:48   ` Ganesh Mahendran
2015-01-29 15:12     ` Sergey Senozhatsky
2015-01-30  7:52       ` Ganesh Mahendran
2015-01-30  8:08         ` Sergey Senozhatsky
2015-01-31  8:50           ` Ganesh Mahendran
2015-01-31 11:07             ` Sergey Senozhatsky
2015-01-31 12:59               ` Ganesh Mahendran
2015-02-02  3:41 Minchan Kim
2015-02-02  5:59 ` Sergey Senozhatsky
2015-02-02  6:18   ` Minchan Kim
2015-02-02  7:06     ` Sergey Senozhatsky
2015-02-03  1:54       ` Sergey Senozhatsky
2015-02-03  3:02         ` Minchan Kim
2015-02-03  3:56           ` Sergey Senozhatsky

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