From: Tejun Heo <tj@kernel.org>
To: Waiman Long <waiman.long@hpe.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>,
Andreas Dilger <adilger.kernel@dilger.ca>,
Christoph Lameter <cl@linux.com>,
linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
Scott J Norton <scott.norton@hpe.com>,
Douglas Hatch <doug.hatch@hpe.com>,
Toshimitsu Kani <toshi.kani@hpe.com>
Subject: Re: [PATCH 2/3] percpu_stats: Simple per-cpu statistics count helper functions
Date: Wed, 6 Apr 2016 18:54:24 -0400 [thread overview]
Message-ID: <20160406225424.GK24661@htj.duckdns.org> (raw)
In-Reply-To: <570584F1.10909@hpe.com>
Hello,
On Wed, Apr 06, 2016 at 05:51:45PM -0400, Waiman Long wrote:
> >>+ /*
> >>+ * If a statistics count is in the middle of being updated, it
> >>+ * is possible that the above clearing may not work. So we need
> >>+ * to double check again to make sure that the counters are really
> >>+ * cleared. Still there is a still a very small chance that the
> >>+ * second clearing does not work.
> >>+ */
> >>+ for_each_possible_cpu(cpu) {
> >>+ unsigned long *pstats = per_cpu_ptr(pcs->stats, cpu);
> >>+ int stat;
> >>+
> >>+ for (stat = 0; stat< pcs->nstats; stat++, pstats++)
> >>+ if (*pstats)
> >>+ *pstats = 0;
> >>+ }
> >I don't think this is acceptable.
>
> I am not sure what you mean here by not acceptable. Please enlighten me on
> that.
Hmmm... I thought that was pretty clear. Try-twice-and-we-are-probably-okay
is simply not acceptable. Please make it watertight.
Thanks.
--
tejun
next prev parent reply other threads:[~2016-04-06 22:54 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-02 3:09 [PATCH 0/3] ext4: Improve parallel I/O performance on NVDIMM Waiman Long
2016-04-02 3:09 ` [PATCH 1/3] ext4: Pass in DIO_SKIP_DIO_COUNT flag if inode_dio_begin() called Waiman Long
2016-04-02 3:09 ` [PATCH 2/3] percpu_stats: Simple per-cpu statistics count helper functions Waiman Long
2016-04-04 7:36 ` Nikolay Borisov
2016-04-04 17:11 ` Waiman Long
2016-04-04 19:09 ` Christoph Lameter
2016-04-06 21:53 ` Waiman Long
2016-04-04 16:02 ` Tejun Heo
2016-04-06 19:52 ` Waiman Long
2016-04-06 21:51 ` Waiman Long
2016-04-06 22:54 ` Tejun Heo [this message]
2016-04-07 15:58 ` Waiman Long
2016-04-07 16:06 ` Tejun Heo
2016-04-07 18:52 ` Waiman Long
2016-04-07 18:58 ` Tejun Heo
2016-04-07 20:37 ` Waiman Long
2016-04-07 20:41 ` Tejun Heo
2016-04-07 21:38 ` Waiman Long
2016-04-02 3:09 ` [PATCH 3/3] ext4: Make cache hits/misses per-cpu counts Waiman Long
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