From: Dipankar Sarma <dipankar@in.ibm.com>
To: Andrew Morton <akpm@osdl.org>
Cc: linux-kernel@vger.kernel.org, paulmck@us.ibm.com, dada1@cosmosbay.com
Subject: Re: [PATCH 2/2] fix file counting
Date: Sat, 18 Feb 2006 14:55:17 +0530 [thread overview]
Message-ID: <20060218092517.GP29846@in.ibm.com> (raw)
In-Reply-To: <20060218010414.1f8d6782.akpm@osdl.org>
On Sat, Feb 18, 2006 at 01:04:14AM -0800, Andrew Morton wrote:
> Dipankar Sarma <dipankar@in.ibm.com> wrote:
> Fair enough.
>
> What do you think of these changes?
>
>
> - Nuke the blank line between "}" and EXPORT_SYMBOL(). That's never seemed
> pointful to me.
Sounds good.
>
> - Make the get_max_files export use _GPL - only unix.ko uses it.
Always good. I just didn't want to be the one :)
> - Use `-1' in the arg to percpu_counter_mod() rather than `-1L'. The
> compiler will dtrt and we shouldn't be peering inside percpu_counter
> internals here anyway.
>
> - Scrub that - use percpu_counter_dec() and percpu_counter_inc().
Gah! I missed those APIs. Makes perfect sense.
>
> - percpu_counters can be inaccurate on big SMP. Before we actually fail a
> get_empty_filp() attempt, use the (new in -mm) expensive
> percpu_counter_sum() to check whether we're really over the limit.
> - if (get_nr_files() >= files_stat.max_files &&
> - !capable(CAP_SYS_ADMIN))
> - goto over;
> + if (get_nr_files() >= files_stat.max_files && !capable(CAP_SYS_ADMIN)) {
> + /*
> + * percpu_counters are inaccurate. Do an expensive check before
> + * we go and fail.
> + */
> + if (percpu_counter_sum(&nr_files) >= files_stat.max_files)
> + goto over;
> + }
Slight optimization -
if (get_nr_files() >= files_stat.max_files) {
if (capable(CAP_SYS_ADMIN)) {
/*
* percpu_counters are inaccurate. Do an expensive check before
* we go and fail.
*/
if (percpu_counter_sum(&nr_files) >=
files_stat.max_files)
goto over;
} else
goto over;
}
>
>
> - Make get_nr_files() static. Which is just as well - any callers might
> want the percpu_counter_sum() treatment. In which case we'd be better off
> exporting some
>
> bool are_files_over_limit(how_many_i_want);
Well, as of now there is none (xfs use was removed a few months ago).
So, I removed the EXPORT_SYMBOL for get_nr_files() and forgot to
make it static. Your patch does the right thing.
Thanks
Dipankar
next prev parent reply other threads:[~2006-02-18 9:26 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-17 15:41 [PATCH 0/2] RCU updates Dipankar Sarma
2006-02-17 15:43 ` [PATCH 1/2] rcu batch tuning Dipankar Sarma
2006-02-17 15:46 ` [PATCH 2/2] fix file counting Dipankar Sarma
2006-02-18 9:04 ` Andrew Morton
2006-02-18 9:25 ` Dipankar Sarma [this message]
2006-02-18 9:45 ` Andrew Morton
2006-02-18 10:06 ` Dipankar Sarma
2006-02-18 10:10 ` Andrew Morton
2006-02-18 10:44 ` Dipankar Sarma
2006-02-18 12:14 ` Christoph Hellwig
2006-02-18 12:31 ` Arjan van de Ven
2006-02-20 22:36 ` [2.6 patch] make UNIX a bool Adrian Bunk
2006-02-17 20:33 ` [PATCH 1/2] rcu batch tuning Dipankar Sarma
2006-02-18 8:45 ` Andrew Morton
2006-02-18 9:15 ` Dipankar Sarma
-- strict thread matches above, loose matches on Subject: below --
2006-01-26 18:40 [patch 0/2] RCU: fix various latency/oom issues Dipankar Sarma
2006-01-26 18:41 ` [patch 1/2] rcu batch tuning Dipankar Sarma
2006-01-26 18:42 ` [patch 2/2] fix file counting Dipankar Sarma
2006-01-26 20:15 ` Eric Dumazet
2006-01-27 22:54 ` Andrew Morton
2006-01-27 23:14 ` Paul E. McKenney
2006-01-27 23:28 ` Andrew Morton
2006-01-28 18:42 ` Dipankar Sarma
2006-01-28 18:51 ` Andrew Morton
2006-01-28 19:10 ` Dipankar Sarma
2006-01-30 17:00 ` Dipankar Sarma
2006-01-31 10:33 ` Eric Dumazet
2006-01-31 20:19 ` Dipankar Sarma
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