From: David Laight <David.Laight@ACULAB.COM>
To: 'Christoph Hellwig' <hch@lst.de>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <maxime.ripard@bootlin.com>,
Sean Paul <sean@poorly.run>, David Airlie <airlied@linux.ie>,
Daniel Vetter <daniel@ffwll.ch>,
Jani Nikula <jani.nikula@linux.intel.com>,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
"Ian Abbott" <abbotti@mev.co.uk>,
H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Intel Linux Wireless <linuxwifi@intel.com>,
"moderated list:ARM PORT" <linux-arm-kernel@lists.infradead.org>,
"dri-devel@lists.freedesktop.org"
<dri-devel@lists.freedesktop.org>,
"intel-gfx@lists.freedesktop.org"
<intel-gfx@lists.freedesktop.org>,
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"linux-media@vger.kernel.org" <linux-media@vger.kernel.org>,
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"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
"linux-s390@vger.kernel.org" <linux-s390@vger.kernel.org>,
"devel@driverdev.osuosl.org" <devel@driverdev.osuosl.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH 16/16] dma-mapping: use exact allocation in dma_alloc_contiguous
Date: Fri, 14 Jun 2019 14:15:44 +0000 [thread overview]
Message-ID: <a90cf7ec5f1c4166b53c40e06d4d832a@AcuMS.aculab.com> (raw)
In-Reply-To: <20190614134726.3827-17-hch@lst.de>
From: Christoph Hellwig
> Sent: 14 June 2019 14:47
>
> Many architectures (e.g. arm, m68 and sh) have always used exact
> allocation in their dma coherent allocator, which avoids a lot of
> memory waste especially for larger allocations. Lift this behavior
> into the generic allocator so that dma-direct and the generic IOMMU
> code benefit from this behavior as well.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> include/linux/dma-contiguous.h | 8 +++++---
> kernel/dma/contiguous.c | 17 +++++++++++------
> 2 files changed, 16 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
> index c05d4e661489..2e542e314acf 100644
> --- a/include/linux/dma-contiguous.h
> +++ b/include/linux/dma-contiguous.h
> @@ -161,15 +161,17 @@ static inline struct page *dma_alloc_contiguous(struct device *dev, size_t size,
> gfp_t gfp)
> {
> int node = dev ? dev_to_node(dev) : NUMA_NO_NODE;
> - size_t align = get_order(PAGE_ALIGN(size));
> + void *cpu_addr = alloc_pages_exact_node(node, size, gfp);
>
> - return alloc_pages_node(node, gfp, align);
> + if (!cpu_addr)
> + return NULL;
> + return virt_to_page(p);
> }
Does this still guarantee that requests for 16k will not cross a 16k boundary?
It looks like you are losing the alignment parameter.
There may be drivers and hardware that also require 12k allocates
to not cross 16k boundaries (etc).
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2019-06-14 14:15 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-14 13:47 use exact allocation for dma coherent memory Christoph Hellwig
2019-06-14 13:47 ` [PATCH 01/16] media: videobuf-dma-contig: use dma_mmap_coherent Christoph Hellwig
2019-06-14 13:47 ` [PATCH 02/16] drm/ati_pcigart: stop using drm_pci_alloc Christoph Hellwig
2019-06-14 13:47 ` [PATCH 03/16] drm/i915: " Christoph Hellwig
2019-06-14 16:45 ` [Intel-gfx] " Ville Syrjälä
2019-06-14 13:47 ` [PATCH 04/16] drm: move drm_pci_{alloc,free} to drm_legacy Christoph Hellwig
2019-06-14 13:47 ` [PATCH 05/16] drm: don't mark pages returned from drm_pci_alloc reserved Christoph Hellwig
2019-06-14 13:47 ` [PATCH 06/16] drm: don't pass __GFP_COMP to dma_alloc_coherent in drm_pci_alloc Christoph Hellwig
2019-06-14 13:47 ` [PATCH 07/16] IB/hfi1: stop passing bogus gfp flags arguments to dma_alloc_coherent Christoph Hellwig
2019-06-14 13:47 ` [PATCH 08/16] IB/qib: " Christoph Hellwig
2019-06-14 13:47 ` [PATCH 09/16] cnic: " Christoph Hellwig
2019-06-14 13:47 ` [PATCH 10/16] iwlwifi: " Christoph Hellwig
2019-06-14 13:47 ` [PATCH 11/16] s390/ism: " Christoph Hellwig
2019-06-14 13:47 ` [PATCH 12/16] staging/comedi: mark as broken Christoph Hellwig
2019-06-14 14:02 ` Greg KH
2019-06-14 14:48 ` Christoph Hellwig
2019-06-14 15:30 ` Greg KH
2019-06-14 15:34 ` Christoph Hellwig
2019-06-17 13:15 ` Ian Abbott
2019-06-14 13:47 ` [PATCH 13/16] mm: rename alloc_pages_exact_nid to alloc_pages_exact_node Christoph Hellwig
2019-06-14 13:47 ` [PATCH 14/16] mm: use alloc_pages_exact_node to implement alloc_pages_exact Christoph Hellwig
2019-06-14 13:47 ` [PATCH 15/16] dma-mapping: clear __GFP_COMP in dma_alloc_attrs Christoph Hellwig
2019-06-14 13:47 ` [PATCH 16/16] dma-mapping: use exact allocation in dma_alloc_contiguous Christoph Hellwig
2019-06-14 14:15 ` David Laight [this message]
2019-06-14 14:50 ` 'Christoph Hellwig'
2019-06-14 15:01 ` David Laight
2019-06-14 15:05 ` 'Christoph Hellwig'
2019-06-14 15:05 ` Robin Murphy
2019-06-14 15:08 ` 'Christoph Hellwig'
2019-06-14 15:16 ` David Laight
2019-06-17 8:21 ` use exact allocation for dma coherent memory Dan Carpenter
2019-06-17 8:33 ` Christoph Hellwig
2019-06-19 16:29 ` Jason Gunthorpe
2019-06-20 10:51 ` Christoph Hellwig
2019-07-01 8:48 ` Christoph Hellwig
2019-07-02 9:48 ` Arend Van Spriel
2019-07-08 18:43 ` Christoph Hellwig
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