linux-kernel - Re: [tip:core/debugobjects] debugobjects: Reduce contention on the global pool

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Date:   Mon, 6 Feb 2017 23:50:25 +0100
From:   Ingo Molnar <mingo@...nel.org>
To:     Waiman Long <longman@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     hpa@...or.com, tglx@...utronix.de, linux-kernel@...r.kernel.org,
        changbin.du@...el.com, jstancek@...hat.com,
        akpm@...ux-foundation.org, borntraeger@...ibm.com,
        linux-tip-commits@...r.kernel.org
Subject: Re: [tip:core/debugobjects] debugobjects: Reduce contention on the
 global pool_lock


* Waiman Long <longman@...hat.com> wrote:

> On 02/05/2017 05:03 AM, Ingo Molnar wrote:
> > * tip-bot for Waiman Long <tipbot@...or.com> wrote:
> >
> >> ---
> >>  lib/debugobjects.c | 31 ++++++++++++++++++++++---------
> >>  1 file changed, 22 insertions(+), 9 deletions(-)
> >>
> >> diff --git a/lib/debugobjects.c b/lib/debugobjects.c
> >> index dc78217..5476bbe 100644
> >> --- a/lib/debugobjects.c
> >> +++ b/lib/debugobjects.c
> >> @@ -172,25 +172,38 @@ alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
> >>  
> >>  /*
> >>   * workqueue function to free objects.
> >> + *
> >> + * To reduce contention on the global pool_lock, the actual freeing of
> >> + * debug objects will be delayed if the pool_lock is busy. We also free
> >> + * the objects in a batch of 4 for each lock/unlock cycle.
> >>   */
> >> +#define ODEBUG_FREE_BATCH	4
> >>  static void free_obj_work(struct work_struct *work)
> >>  {
> > Please put an extra newline before function definitions.
> >
> > Looks good otherwise!
> >
> > Thanks,
> >
> > 	Ingo
> 
> 
> Sure, I can do that. BTW the debugobjects patch was also pull into the
> -mm tree a little while ago. Will that be a problem?

Should not be a problem usually, Andrew typically drops such patches if they show 
up in a maintainer tree via linux-next.

And once accepted we don't silently drop patches from -tip hosted maintainer 
trees, so this is a reliable workflow.

Thanks,

	Ingo