All of lore.kernel.org
 help / color / mirror / Atom feed
From: Thomas Gleixner <tglx@linutronix.de>
To: Michal Hocko <mhocko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Tejun Heo <tj@kernel.org>, Peter Zijlstra <peterz@infradead.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Mel Gorman <mgorman@suse.de>,
	linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: drop hotplug lock from lru_add_drain_all
Date: Tue, 14 Nov 2017 16:05:21 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.20.1711141605050.2044@nanos> (raw)
In-Reply-To: <20171114143200.brmgskoqxjlrhrzx@dhcp22.suse.cz>

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
> 

WARNING: multiple messages have this Message-ID
From: Thomas Gleixner <tglx@linutronix.de>
To: Michal Hocko <mhocko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Tejun Heo <tj@kernel.org>, Peter Zijlstra <peterz@infradead.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Mel Gorman <mgorman@suse.de>,
	linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: drop hotplug lock from lru_add_drain_all
Date: Tue, 14 Nov 2017 16:05:21 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.20.1711141605050.2044@nanos> (raw)
In-Reply-To: <20171114143200.brmgskoqxjlrhrzx@dhcp22.suse.cz>

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
> 

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

  reply	other threads:[~2017-11-14 15:05 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-14 13:53 Michal Hocko
2017-11-14 13:53 ` Michal Hocko
2017-11-14 14:13 ` Thomas Gleixner
2017-11-14 14:13   ` Thomas Gleixner
2017-11-14 14:23   ` Michal Hocko
2017-11-14 14:23     ` Michal Hocko
2017-11-14 14:32     ` Michal Hocko
2017-11-14 14:32       ` Michal Hocko
2017-11-14 15:05       ` Thomas Gleixner [this message]
2017-11-14 15:05         ` Thomas Gleixner
2017-11-14 15:11         ` Thomas Gleixner
2017-11-14 15:11           ` Thomas Gleixner
2017-11-14 15:14         ` Michal Hocko
2017-11-14 15:14           ` Michal Hocko
2017-11-16 12:05 Michal Hocko
2017-11-16 12:05 ` Michal Hocko

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=alpine.DEB.2.20.1711141605050.2044@nanos \
    --to=tglx@linutronix.de \
    --cc=akpm@linux-foundation.org \
    --cc=hannes@cmpxchg.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mgorman@suse.de \
    --cc=mhocko@kernel.org \
    --cc=peterz@infradead.org \
    --cc=tj@kernel.org \
    --subject='Re: [PATCH] mm: drop hotplug lock from lru_add_drain_all' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.