Messages in this thread | | | Date | Wed, 27 Sep 2017 17:05:55 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH v2 1/2] pid: Replace pid bitmap implementation with IDR API |
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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.
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