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From: Christoph Hellwig <hch@infradead.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: Matthew Wilcox <willy6545@gmail.com>,
	"Luis R. Rodriguez" <mcgrof@kernel.org>,
	Christoph Hellwig <hch@infradead.org>,
	Dan Carpenter <dan.carpenter@oracle.com>,
	Julia Lawall <julia.lawall@lip6.fr>,
	linux-mm@kvack.org, cl@linux.com, Jan Kara <jack@suse.cz>,
	matthew@wil.cx, x86@kernel.org, luto@amacapital.net,
	martin.petersen@oracle.com, jthumshirn@suse.de,
	broonie@kernel.org, Juergen Gross <jgross@suse.com>,
	linux-spi@vger.kernel.org, Joerg Roedel <joro@8bytes.org>,
	linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
	"lsf-pc@lists.linux-foundation.org"
	<lsf-pc@lists.linux-foundation.org>
Subject: Re: [LSF/MM TOPIC NOTES] x86 ZONE_DMA love
Date: Thu, 3 May 2018 05:13:22 -0700	[thread overview]
Message-ID: <20180503121322.GA14864@infradead.org> (raw)
In-Reply-To: <20180503120338.GG4535@dhcp22.suse.cz>

On Thu, May 03, 2018 at 02:03:38PM +0200, Michal Hocko wrote:
> On Sat 28-04-18 19:10:47, Matthew Wilcox wrote:
> > Another way we could approach this is to get rid of ZONE_DMA. Make GFP_DMA
> > a flag which doesn't map to a zone. Rather, it redirects to a separate
> > allocator. At boot, we hand all memory under 16MB to the DMA allocator. The
> > DMA allocator can have a shrinker which just hands back all the memory once
> > we're under memory pressure (if it's never had an allocation).
> 
> Yeah, that was exactly the plan with the CMA allocator... We wouldn't
> need the shrinker because who cares about 16MB which is not usable
> anyway.

The CMA pool sounds fine.  But please kill GFP_DMA off first / at the
same time.  95% of the users are either completely bogus or should be
using the DMA API, and the few other can use the new allocator directly.

  reply	other threads:[~2018-05-03 12:13 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-26 21:54 Luis R. Rodriguez
2018-04-27  1:09 ` [Lsf-pc] " Rik van Riel
2018-04-27  5:35 ` Christoph Hellwig
2018-04-27  7:18   ` Michal Hocko
2018-04-27 16:07     ` Christopher Lameter
2018-04-27 16:18       ` Matthew Wilcox
2018-04-27 16:36         ` Christopher Lameter
2018-04-28  8:33           ` Christoph Hellwig
2018-04-27 16:37       ` Michal Hocko
2018-04-28  8:33       ` Christoph Hellwig
2018-04-28  8:30     ` Christoph Hellwig
2018-04-27 16:14   ` Luis R. Rodriguez
2018-04-27 16:28     ` Matthew Wilcox
2018-04-28  8:42     ` Christoph Hellwig
2018-04-28 18:55       ` Luis R. Rodriguez
2018-04-28 19:46         ` Julia Lawall
2018-04-28 20:41           ` Matthew Wilcox
2018-04-29 14:34             ` Julia Lawall
     [not found]         ` <CAFhKne8u7KcBkpgiQ0fFZyh5_EorfY-_MJJaEYk3feCOd9LsRQ@mail.gmail.com>
2018-05-03 12:03           ` Michal Hocko
2018-05-03 12:13             ` Christoph Hellwig [this message]
2018-05-03  8:20 ` Geert Uytterhoeven
2018-05-05 16:08 ` Are media drivers abusing of GFP_DMA? - was: " Mauro Carvalho Chehab
2018-05-07 13:26   ` Laurent Pinchart
2018-05-07 15:19     ` Mauro Carvalho Chehab
2018-05-14  8:00       ` Fabien DESSENNE
2018-05-14 10:35         ` Mauro Carvalho Chehab
2018-05-14 10:39           ` Mauro Carvalho Chehab
2018-05-15  7:30             ` Fabien DESSENNE
2018-05-15  8:27               ` Laurent Pinchart
2018-05-15 10:30                 ` Mauro Carvalho Chehab
2018-05-15 16:24           ` Luis R. Rodriguez
2018-05-10  4:39   ` Yasunari.Takiguchi

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