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From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Ingo Molnar <mingo@redhat.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-arch@vger.kernel.org
Subject: Re: [PATCH] mm: create a separate slab for page->ptl allocation
Date: Wed, 6 Nov 2013 15:21:55 +0200	[thread overview]
Message-ID: <20131106132155.GA22132@shutemov.name> (raw)
In-Reply-To: <20131106093131.GU28601@twins.programming.kicks-ass.net>

On Wed, Nov 06, 2013 at 10:31:31AM +0100, Peter Zijlstra wrote:
> On Wed, Nov 06, 2013 at 01:13:11AM +0200, Kirill A. Shutemov wrote:
> > I would like to get rid of __ptlock_alloc()/__ptlock_free() too, but I
> > don't see a way within C: we need to know sizeof(spinlock_t) on
> > preprocessor stage.
> > 
> > We can have a hack on kbuild level: write small helper program to find out
> > sizeof(spinlock_t) before start building and turn it into define.
> > But it's overkill from my POV. And cross-compilation will be a fun.
> 
> Ah, I just remembered, we have such a thing!

Great!

> @@ -1354,7 +1356,7 @@ static inline bool ptlock_init(struct page *page)
>  	 * slab code uses page->slab_cache and page->first_page (for tail
>  	 * pages), which share storage with page->ptl.
>  	 */
> -	VM_BUG_ON(page->ptl);
> +	VM_BUG_ON(*(unsigned long *)&page->ptl);

Huh? Why not direct cast to unsigned long?

VM_BUG_ON((unsigned long)page->ptl);

Otherwise:

Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>


-- 
 Kirill A. Shutemov

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  parent reply	other threads:[~2013-11-06 14:18 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-22 11:53 [PATCH] mm: create a separate slab for page->ptl allocation Kirill A. Shutemov
2013-10-22 12:55 ` Fengguang Wu
2013-11-04 10:42 ` Kirill A. Shutemov
2013-11-05 23:01 ` Andrew Morton
2013-11-05 22:42   ` Kirill A. Shutemov
2013-11-05 23:56     ` Andrew Morton
2013-11-05 23:13       ` Kirill A. Shutemov
2013-11-06  0:43         ` Andrew Morton
2013-11-06  9:31         ` Peter Zijlstra
2013-11-06 11:18           ` Peter Zijlstra
2013-11-06 13:31             ` lockref: Use bloated_spinlocks to avoid explicit config dependencies Kirill A. Shutemov
2013-11-06 14:32               ` Peter Zijlstra
2013-11-06 13:21           ` Kirill A. Shutemov [this message]
2013-11-06 14:30             ` [PATCH] mm: create a separate slab for page->ptl allocation Peter Zijlstra
2013-11-06 10:34         ` Will Deacon
2013-11-06 10:49           ` Geert Uytterhoeven
2013-11-06 11:02           ` Peter Zijlstra

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