linux-kernel - Re: [PATCH v3 RESEND 3/6] bitmap: Make bitmap

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Date: Mon, 12 Feb 2024 16:01:38 +0200
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Herve Codina <herve.codina@...tlin.com>
Cc: Vadim Fedorenko <vadim.fedorenko@...ux.dev>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Yury Norov <yury.norov@...il.com>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
	linuxppc-dev@...ts.ozlabs.org, Andrew Lunn <andrew@...n.ch>,
	Mark Brown <broonie@...nel.org>,
	Christophe Leroy <christophe.leroy@...roup.eu>,
	Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Subject: Re: [PATCH v3 RESEND 3/6] bitmap: Make bitmap_onto() available to
 users

On Mon, Feb 12, 2024 at 02:37:53PM +0100, Herve Codina wrote:
> On Mon, 12 Feb 2024 14:27:16 +0200
> Andy Shevchenko <andriy.shevchenko@...ux.intel.com> wrote:
> > On Mon, Feb 12, 2024 at 08:56:31AM +0100, Herve Codina wrote:
> > > Currently the bitmap_onto() is available only for CONFIG_NUMA=y case,
> > > while some users may benefit out of it and being independent to NUMA
> > > code.
> > > 
> > > Make it available to users by moving out of ifdeffery and exporting for
> > > modules.  
> > 
> > Wondering if you are trying to have something like
> > https://lore.kernel.org/lkml/20230926052007.3917389-1-andriy.shevchenko@linux.intel.com/
> 
> Yes, it looks like.
> Can you confirm that your bitmap_scatter() do the same operations as the
> existing bitmap_onto() ?

I have test cases to be 100% sure, but on the first glance, yes it does with
the adjustment to the atomicity of the operations (which I do not understand
why be atomic in the original bitmap_onto() implementation).

This actually gives a question if we should use your approach or mine.
At least the help of bitmap_onto() is kinda hard to understand.

> If so, your bitmap_gather() will match my bitmap_off() (patch 4 in this
> series).

Yes.

-- 
With Best Regards,
Andy Shevchenko