From: mhocko@kernel.org (Michal Hocko)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] mm: cma: honor __GFP_ZERO flag in cma_alloc()
Date: Wed, 13 Jun 2018 15:39:13 +0200 [thread overview]
Message-ID: <20180613133913.GD20315@dhcp22.suse.cz> (raw)
In-Reply-To: <20180613125546.GB32016@infradead.org>
On Wed 13-06-18 05:55:46, Christoph Hellwig wrote:
> On Wed, Jun 13, 2018 at 02:40:00PM +0200, Marek Szyprowski wrote:
> > It is not only the matter of the spinlocks. GFP_ATOMIC is not supported
> > by the
> > memory compaction code, which is used in alloc_contig_range(). Right, this
> > should be also noted in the documentation.
>
> Documentation is good, asserts are better. The code should reject any
> flag not explicitly supported, or even better have its own flags type
> with the few actually supported flags.
Agreed. Is the cma allocator used for anything other than GFP_KERNEL
btw.? If not then, shouldn't we simply drop the gfp argument altogether
rather than give users a false hope for differen gfp modes that are not
really supported and grow broken code?
--
Michal Hocko
SUSE Labs
WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@kernel.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>,
Matthew Wilcox <willy@infradead.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Andrew Morton <akpm@linux-foundation.org>,
Michal Nazarewicz <mina86@mina86.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [PATCH] mm: cma: honor __GFP_ZERO flag in cma_alloc()
Date: Wed, 13 Jun 2018 15:39:13 +0200 [thread overview]
Message-ID: <20180613133913.GD20315@dhcp22.suse.cz> (raw)
In-Reply-To: <20180613125546.GB32016@infradead.org>
On Wed 13-06-18 05:55:46, Christoph Hellwig wrote:
> On Wed, Jun 13, 2018 at 02:40:00PM +0200, Marek Szyprowski wrote:
> > It is not only the matter of the spinlocks. GFP_ATOMIC is not supported
> > by the
> > memory compaction code, which is used in alloc_contig_range(). Right, this
> > should be also noted in the documentation.
>
> Documentation is good, asserts are better. The code should reject any
> flag not explicitly supported, or even better have its own flags type
> with the few actually supported flags.
Agreed. Is the cma allocator used for anything other than GFP_KERNEL
btw.? If not then, shouldn't we simply drop the gfp argument altogether
rather than give users a false hope for differen gfp modes that are not
really supported and grow broken code?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-06-13 13:39 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20180613085851eucas1p20337d050face8ff8ea87674e16a9ccd2@eucas1p2.samsung.com>
2018-06-13 8:58 ` [PATCH] mm: cma: honor __GFP_ZERO flag in cma_alloc() Marek Szyprowski
2018-06-13 8:58 ` Marek Szyprowski
2018-06-13 12:24 ` Matthew Wilcox
2018-06-13 12:24 ` Matthew Wilcox
2018-06-13 12:40 ` Marek Szyprowski
2018-06-13 12:40 ` Marek Szyprowski
2018-06-13 12:55 ` Christoph Hellwig
2018-06-13 12:55 ` Christoph Hellwig
2018-06-13 13:39 ` Michal Hocko [this message]
2018-06-13 13:39 ` Michal Hocko
2018-07-02 13:23 ` Marek Szyprowski
2018-07-02 13:23 ` Marek Szyprowski
2018-07-02 13:30 ` Christoph Hellwig
2018-07-02 13:30 ` Christoph Hellwig
2018-07-09 10:32 ` Marek Szyprowski
2018-07-09 10:32 ` Marek Szyprowski
2018-07-02 13:32 ` Michal Hocko
2018-07-02 13:32 ` Michal Hocko
2018-07-09 10:31 ` Marek Szyprowski
2018-07-09 10:31 ` Marek Szyprowski
2018-06-13 12:52 ` Christoph Hellwig
2018-06-13 12:52 ` Christoph Hellwig
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