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Re: [PATCH v7 1/4] lib/percpu-list: Per-cpu list with associated per-cpu locks

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On Tue 12-04-16 18:54:43, Waiman Long wrote:
> Linked list is used everywhere in the Linux kernel. However, if many
> threads are trying to add or delete entries into the same linked list,
> it can create a performance bottleneck.
> 
> This patch introduces a new per-cpu list subystem with associated
> per-cpu locks for protecting each of the lists individually. This
> allows list entries insertion and deletion operations to happen in
> parallel instead of being serialized with a global list and lock.
> 
> List entry insertion is strictly per cpu. List deletion, however, can
> happen in a cpu other than the one that did the insertion. So we still
> need lock to protect the list. Because of that, there may still be
> a small amount of contention when deletion is being done.
> 
> A new header file include/linux/percpu-list.h will be added with the
> associated pcpu_list_head and pcpu_list_node structures. The following
> functions are provided to manage the per-cpu list:
> 
>  1. int init_pcpu_list_head(struct pcpu_list_head **ppcpu_head)
>  2. void pcpu_list_add(struct pcpu_list_node *node,
> 		       struct pcpu_list_head *head)
>  3. void pcpu_list_del(struct pcpu_list *node)
> 
> Iteration of all the list entries within a group of per-cpu
> lists is done by calling either the pcpu_list_iterate() or
> pcpu_list_iterate_safe() functions in a while loop. They correspond
> to the list_for_each_entry() and list_for_each_entry_safe() macros
> respectively. The iteration states are keep in a pcpu_list_state
> structure that is passed to the iteration functions.
> 
> Signed-off-by: Waiman Long <Waiman.Long@hpe.com>

The patch looks good to me now. So you can add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

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[PATCH v7 0/4] vfs: Use per-cpu list for SB's s_inodes list Waiman Long <Waiman.Long@hpe.com> - 2016-04-13 01:00 +0200
  [PATCH v7 1/4] lib/percpu-list: Per-cpu list with associated per-cpu locks Waiman Long <Waiman.Long@hpe.com> - 2016-04-13 01:10 +0200
    Re: [PATCH v7 1/4] lib/percpu-list: Per-cpu list with associated  per-cpu locks Boqun Feng <boqun.feng@gmail.com> - 2016-04-13 04:20 +0200
      Re: [PATCH v7 1/4] lib/percpu-list: Per-cpu list with associated  per-cpu locks Waiman Long <waiman.long@hpe.com> - 2016-04-13 20:00 +0200
        Re: [PATCH v7 1/4] lib/percpu-list: Per-cpu list with associated  per-cpu locks Boqun Feng <boqun.feng@gmail.com> - 2016-04-15 01:40 +0200
    Re: [PATCH v7 1/4] lib/percpu-list: Per-cpu list with associated  per-cpu locks Christoph Lameter <cl@linux.com> - 2016-04-13 17:10 +0200
      Re: [PATCH v7 1/4] lib/percpu-list: Per-cpu list with associated  per-cpu locks Waiman Long <waiman.long@hpe.com> - 2016-04-13 19:50 +0200
        Re: [PATCH v7 1/4] lib/percpu-list: Per-cpu list with associated  per-cpu locks Christoph Lameter <cl@linux.com> - 2016-04-13 20:10 +0200
    Re: [PATCH v7 1/4] lib/percpu-list: Per-cpu list with associated  per-cpu locks Jan Kara <jack@suse.cz> - 2016-04-14 16:20 +0200
      Re: [PATCH v7 1/4] lib/percpu-list: Per-cpu list with associated  per-cpu locks Waiman Long <waiman.long@hpe.com> - 2016-04-14 20:50 +0200

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