lkml.org 
[lkml]   [2017]   [Nov]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] mm: drop hotplug lock from lru_add_drain_all
On Tue, 14 Nov 2017, Michal Hocko wrote:

> On Tue 14-11-17 15:23:47, Michal Hocko wrote:
> [...]
> > +/*
> > + * Doesn't need any cpu hotplug locking because we do rely on per-cpu
> > + * kworkers being shut down before our page_alloc_cpu_dead callback is
> > + * executed on the offlined cpu
> > + */
> > void lru_add_drain_all(void)
> > {
> > static DEFINE_MUTEX(lock);
>
> Ble the part of the comment didn't go through

Looks good.

Thanks,

tglx

> diff --git a/mm/swap.c b/mm/swap.c
> index 8bfdcab9f83e..1ab8122d2d0c 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -688,6 +688,13 @@ static void lru_add_drain_per_cpu(struct work_struct *dummy)
>
> static DEFINE_PER_CPU(struct work_struct, lru_add_drain_work);
>
> +/*
> + * Doesn't need any cpu hotplug locking because we do rely on per-cpu
> + * kworkers being shut down before our page_alloc_cpu_dead callback is
> + * executed on the offlined cpu.
> + * Calling this function with cpu hotplug locks held can actually lead
> + * to obscure indirect dependencies via WQ context.
> + */
> void lru_add_drain_all(void)
> {
> static DEFINE_MUTEX(lock);
> --
> Michal Hocko
> SUSE Labs
>

\
 
 \ /
  Last update: 2017-11-14 16:06    [W:0.139 / U:0.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site