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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Howard Yen <howardyen@google.com>
Cc: hch@lst.de, m.szyprowski@samsung.com, robin.murphy@arm.com,
	gregkh@linuxfoundation.org, rafael@kernel.org,
	broonie@kernel.org, james@equiv.tech, james.clark@arm.com,
	masahiroy@kernel.org, linux-kernel@vger.kernel.org,
	iommu@lists.linux.dev
Subject: Re: [PATCH v2] dma-coherent: add support for multi coherent rmems per dev
Date: Tue, 6 Feb 2024 17:43:13 +0200	[thread overview]
Message-ID: <ZcJTkQFcVhcGC52Z@smile.fi.intel.com> (raw)
In-Reply-To: <ZcDPn5eLvMwpb7N1@smile.fi.intel.com>

On Mon, Feb 05, 2024 at 02:08:00PM +0200, Andy Shevchenko wrote:
> On Mon, Feb 05, 2024 at 07:23:00AM +0000, Howard Yen wrote:

...

> > @@ -18,15 +18,9 @@ struct dma_coherent_mem {
> >  	unsigned long	*bitmap;
> >  	spinlock_t	spinlock;
> >  	bool		use_dev_dma_pfn_offset;
> > +	struct list_head	node;
> 
> Have you run `pahole`? Here I see wasted bytes for nothing.

On top of that one may make container_of() to be no-op, by placing this member
to be the first one. But, double check this with bloat-o-meter (that it indeed
does better code generation) and on the other hand check if the current first
member is not performance critical and having additional pointer arithmetics is
okay.

> >  };


-- 
With Best Regards,
Andy Shevchenko



  reply	other threads:[~2024-02-06 15:43 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-05  7:23 [PATCH v2] dma-coherent: add support for multi coherent rmems per dev Howard Yen
2024-02-05 12:08 ` Andy Shevchenko
2024-02-06 15:43   ` Andy Shevchenko [this message]
2024-02-08  7:53     ` Howard Yen
2024-02-08 10:56       ` Andy Shevchenko
2024-02-08 14:57         ` Howard Yen

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