From: Oleg Nesterov <oleg@redhat.com>
To: Gargi Sharma <gs051095@gmail.com>
Cc: linux-kernel@vger.kernel.org, riel@surriel.com,
julia.lawall@lip6.fr, akpm@linux-foundation.org,
mingo@kernel.org, pasha.tatashin@oracle.com,
ktkhai@virtuozzo.com
Subject: Re: [PATCH v2 1/2] pid: Replace pid bitmap implementation with IDR API
Date: Wed, 27 Sep 2017 17:05:55 +0200 [thread overview]
Message-ID: <20170927150555.GA1412@redhat.com> (raw)
In-Reply-To: <e4bed733a4f8d7e8462a90a62f3b2fe15700c137.1506488388.git.gs051095@gmail.com>
On 09/27, Gargi Sharma wrote:
>
> @@ -309,7 +168,22 @@ struct pid *alloc_pid(struct pid_namespace *ns)
> tmp = ns;
> pid->level = ns->level;
> for (i = ns->level; i >= 0; i--) {
> - nr = alloc_pidmap(tmp);
> + int pid_min = 1;
> + idr_preload(GFP_KERNEL);
> + spin_lock_irq(&pidmap_lock);
> +
> + /*
> + * init really needs pid 1, but after reaching the maximum
> + * wrap back to RESERVED_PIDS
> + */
> + if (tmp->idr.idr_next > RESERVED_PIDS)
> + pid_min = RESERVED_PIDS;
> +
> + nr = idr_alloc_cyclic(&tmp->idr, pid, pid_min,
> + pid_max, GFP_ATOMIC);
> + spin_unlock_irq(&pidmap_lock);
> + idr_preload_end();
> +
> if (nr < 0) {
> retval = nr;
> goto out_free;
> @@ -346,12 +220,14 @@ struct pid *alloc_pid(struct pid_namespace *ns)
> return pid;
>
> out_unlock:
> - spin_unlock_irq(&pidmap_lock);
> put_pid_ns(ns);
> + spin_unlock_irq(&pidmap_lock);
Why? No need to move put_pid_ns() under pidmap_lock, please remove this change...
> void __init pidhash_init(void)
> {
> + unsigned int pidhash_size;
> +
> pid_hash = alloc_large_system_hash("PID", sizeof(*pid_hash), 0, 18,
> HASH_EARLY | HASH_SMALL | HASH_ZERO,
> &pidhash_shift, NULL,
> 0, 4096);
> + pidhash_size = 1U << pidhash_shift;
> }
Hmm, this change makes no sense. And the next patch kills pidhash_init()
altogether.
Oleg.
next prev parent reply other threads:[~2017-09-27 15:06 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-27 5:06 [PATCH v2 0/2] Replace PID bitmap allocation with IDR API Gargi Sharma
2017-09-27 5:06 ` [PATCH v2 1/2] pid: Replace pid bitmap implementation " Gargi Sharma
2017-09-27 13:09 ` Rik van Riel
2017-09-27 14:06 ` Oleg Nesterov
2017-09-27 15:06 ` Gargi Sharma
2017-09-27 15:15 ` Oleg Nesterov
2017-09-27 15:05 ` Gargi Sharma
2017-09-27 15:05 ` Oleg Nesterov [this message]
2017-10-01 9:15 ` Christoph Hellwig
2017-10-01 10:35 ` Gargi Sharma
2017-10-02 13:14 ` Rik van Riel
2017-10-02 13:05 ` Rik van Riel
2017-09-27 5:06 ` [PATCH v2 2/2] pid: Remove pidhash Gargi Sharma
2017-09-27 15:45 ` Oleg Nesterov
2017-09-27 16:28 ` Oleg Nesterov
2017-09-30 15:41 ` Gargi Sharma
2017-10-02 15:03 ` Oleg Nesterov
2017-10-02 13:35 ` Rik van Riel
2017-10-02 13:45 ` Rik van Riel
2017-10-02 15:21 ` Oleg Nesterov
2017-10-02 15:22 ` Rik van Riel
2017-10-02 16:27 ` Gargi Sharma
2017-09-27 17:18 ` [PATCH v2 0/2] Replace PID bitmap allocation with IDR API Eric W. Biederman
[not found] ` <CAOCi2DESqWV2YPcRTe6NYjx6m6N19ewXbAyfLfeBa23kJiEO9Q@mail.gmail.com>
2017-09-28 19:46 ` Rik van Riel
2017-09-28 20:05 ` Gargi Sharma
2017-09-29 0:35 ` Rik van Riel
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