From: Christoph Hellwig <hch@infradead.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>,
Christopher Lameter <cl@linux.com>,
Levin Alexander <Alexander.Levin@microsoft.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Nicolas Boichat <drinkcat@chromium.org>,
Huaisheng Ye <yehs1@lenovo.com>, Tomasz Figa <tfiga@google.com>,
Will Deacon <will.deacon@arm.com>,
linux-kernel@vger.kernel.org, Pekka Enberg <penberg@kernel.org>,
linux-mm@kvack.org, iommu@lists.linux-foundation.org,
Michal Hocko <mhocko@suse.com>,
linux-arm-kernel@lists.infradead.org,
David Rientjes <rientjes@google.com>,
Matthias Brugger <matthias.bgg@gmail.com>,
yingjoe.chen@mediatek.com, Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Mel Gorman <mgorman@techsingularity.net>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [PATCH v2 0/3] iommu/io-pgtable-arm-v7s: Use DMA32 zone for page tables
Date: Thu, 22 Nov 2018 00:23:36 -0800 [thread overview]
Message-ID: <20181122082336.GA2049@infradead.org> (raw)
In-Reply-To: <c5ccde1e-a711-ad33-537c-2d5a0bd9edd4@arm.com>
On Wed, Nov 21, 2018 at 10:26:26PM +0000, Robin Murphy wrote:
> TBH, if this DMA32 stuff is going to be contentious we could possibly just
> rip out the offending kmem_cache - it seemed like good practice for the
> use-case, but provided kzalloc(SZ_1K, gfp | GFP_DMA32) can be relied upon to
> give the same 1KB alignment and chance of succeeding as the equivalent
> kmem_cache_alloc(), then we could quite easily make do with that instead.
Neither is the slab support for kmalloc, not do kmalloc allocations
have useful alignment apparently (at least if you use slub debug).
But I do agree with the sentiment of not wanting to spread GFP_DMA32
futher into the slab allocator.
I think you want a simple genalloc allocator for this rather special
use case.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Pekka Enberg <penberg@kernel.org>,
Nicolas Boichat <drinkcat@chromium.org>,
Michal Hocko <mhocko@suse.com>,
Andrew Morton <akpm@linux-foundation.org>,
Huaisheng Ye <yehs1@lenovo.com>,
linux-mm@kvack.org, Will Deacon <will.deacon@arm.com>,
linux-kernel@vger.kernel.org,
Matthew Wilcox <willy@infradead.org>,
Levin Alexander <Alexander.Levin@microsoft.com>,
Tomasz Figa <tfiga@google.com>,
iommu@lists.linux-foundation.org,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Vlastimil Babka <vbabka@suse.cz>,
David Rientjes <rientjes@google.com>,
Matthias Brugger <matthias.bgg@gmail.com>,
yingjoe.chen@mediatek.com, Christopher Lameter <cl@linux.com>,
Mel Gorman <mgorman@techsingularity.net>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 0/3] iommu/io-pgtable-arm-v7s: Use DMA32 zone for page tables
Date: Thu, 22 Nov 2018 00:23:36 -0800 [thread overview]
Message-ID: <20181122082336.GA2049@infradead.org> (raw)
In-Reply-To: <c5ccde1e-a711-ad33-537c-2d5a0bd9edd4@arm.com>
On Wed, Nov 21, 2018 at 10:26:26PM +0000, Robin Murphy wrote:
> TBH, if this DMA32 stuff is going to be contentious we could possibly just
> rip out the offending kmem_cache - it seemed like good practice for the
> use-case, but provided kzalloc(SZ_1K, gfp | GFP_DMA32) can be relied upon to
> give the same 1KB alignment and chance of succeeding as the equivalent
> kmem_cache_alloc(), then we could quite easily make do with that instead.
Neither is the slab support for kmalloc, not do kmalloc allocations
have useful alignment apparently (at least if you use slub debug).
But I do agree with the sentiment of not wanting to spread GFP_DMA32
futher into the slab allocator.
I think you want a simple genalloc allocator for this rather special
use case.
WARNING: multiple messages have this Message-ID (diff)
From: hch@infradead.org (Christoph Hellwig)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 0/3] iommu/io-pgtable-arm-v7s: Use DMA32 zone for page tables
Date: Thu, 22 Nov 2018 00:23:36 -0800 [thread overview]
Message-ID: <20181122082336.GA2049@infradead.org> (raw)
In-Reply-To: <c5ccde1e-a711-ad33-537c-2d5a0bd9edd4@arm.com>
On Wed, Nov 21, 2018 at 10:26:26PM +0000, Robin Murphy wrote:
> TBH, if this DMA32 stuff is going to be contentious we could possibly just
> rip out the offending kmem_cache - it seemed like good practice for the
> use-case, but provided kzalloc(SZ_1K, gfp | GFP_DMA32) can be relied upon to
> give the same 1KB alignment and chance of succeeding as the equivalent
> kmem_cache_alloc(), then we could quite easily make do with that instead.
Neither is the slab support for kmalloc, not do kmalloc allocations
have useful alignment apparently (at least if you use slub debug).
But I do agree with the sentiment of not wanting to spread GFP_DMA32
futher into the slab allocator.
I think you want a simple genalloc allocator for this rather special
use case.
next prev parent reply other threads:[~2018-11-22 8:23 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-11 9:03 [PATCH v2 0/3] iommu/io-pgtable-arm-v7s: Use DMA32 zone for page tables Nicolas Boichat
2018-11-11 9:03 ` Nicolas Boichat
2018-11-11 9:03 ` Nicolas Boichat
2018-11-11 9:03 ` [PATCH v2 1/3] mm: slab/slub: Add check_slab_flags function to check for valid flags Nicolas Boichat
2018-11-11 9:03 ` Nicolas Boichat
2018-11-11 9:03 ` Nicolas Boichat
2018-11-11 9:03 ` [PATCH v2 2/3] mm: Add support for SLAB_CACHE_DMA32 Nicolas Boichat
2018-11-11 9:03 ` Nicolas Boichat
2018-11-11 9:03 ` Nicolas Boichat
2018-11-21 18:32 ` Christopher Lameter
2018-11-21 18:32 ` Christopher Lameter
2018-11-22 0:52 ` Nicolas Boichat
2018-11-22 0:52 ` Nicolas Boichat
2018-11-22 0:52 ` Nicolas Boichat
2018-11-11 9:03 ` [PATCH v2 3/3] iommu/io-pgtable-arm-v7s: Request DMA32 memory, and improve debugging Nicolas Boichat
2018-11-11 9:03 ` Nicolas Boichat
2018-11-11 9:03 ` Nicolas Boichat
2018-11-21 16:46 ` Will Deacon
2018-11-21 16:46 ` Will Deacon
2018-11-21 17:38 ` Christopher Lameter
2018-11-21 17:38 ` Christopher Lameter
2018-11-21 17:43 ` Robin Murphy
2018-11-21 17:43 ` Robin Murphy
2018-11-21 18:18 ` Christopher Lameter
2018-11-21 18:18 ` Christopher Lameter
2018-11-21 18:02 ` Michal Hocko
2018-11-21 18:02 ` Michal Hocko
2018-11-22 1:20 ` Nicolas Boichat
2018-11-22 1:20 ` Nicolas Boichat
2018-11-22 1:20 ` Nicolas Boichat
2018-11-23 12:15 ` Vlastimil Babka
2018-11-23 12:15 ` Vlastimil Babka
2018-11-21 18:20 ` [PATCH v2 0/3] iommu/io-pgtable-arm-v7s: Use DMA32 zone for page tables Christopher Lameter
2018-11-21 18:20 ` Christopher Lameter
2018-11-21 21:38 ` Matthew Wilcox
2018-11-21 21:38 ` Matthew Wilcox
2018-11-21 21:38 ` Matthew Wilcox
2018-11-21 22:26 ` Robin Murphy
2018-11-21 22:26 ` Robin Murphy
2018-11-21 22:26 ` Robin Murphy
2018-11-22 1:05 ` Nicolas Boichat
2018-11-22 1:05 ` Nicolas Boichat
2018-11-22 1:05 ` Nicolas Boichat
2018-11-22 2:35 ` Matthew Wilcox
2018-11-22 2:35 ` Matthew Wilcox
2018-11-22 2:35 ` Matthew Wilcox
2018-11-22 5:56 ` Nicolas Boichat
2018-11-22 5:56 ` Nicolas Boichat
2018-11-22 5:56 ` Nicolas Boichat
2018-11-22 8:26 ` Christoph Hellwig
2018-11-22 8:26 ` Christoph Hellwig
2018-11-22 8:26 ` Christoph Hellwig
2018-11-22 15:16 ` Matthew Wilcox
2018-11-22 15:16 ` Matthew Wilcox
2018-11-22 15:16 ` Matthew Wilcox
2018-11-22 15:19 ` Christoph Hellwig
2018-11-22 15:19 ` Christoph Hellwig
2018-11-22 15:19 ` Christoph Hellwig
2018-11-22 8:23 ` Christoph Hellwig [this message]
2018-11-22 8:23 ` Christoph Hellwig
2018-11-22 8:23 ` Christoph Hellwig
2018-11-23 3:04 ` Nicolas Boichat
2018-11-23 3:04 ` Nicolas Boichat
2018-11-23 3:04 ` Nicolas Boichat
2018-11-23 5:37 ` Nicolas Boichat
2018-11-23 5:37 ` Nicolas Boichat
2018-11-23 5:37 ` Nicolas Boichat
2018-11-23 12:23 ` Vlastimil Babka
2018-11-23 12:23 ` Vlastimil Babka
2018-11-23 12:23 ` Vlastimil Babka
2018-11-23 12:30 ` Michal Hocko
2018-11-23 12:30 ` Michal Hocko
2018-11-23 12:30 ` Michal Hocko
2018-11-26 8:02 ` Christoph Hellwig
2018-11-26 8:02 ` Christoph Hellwig
2018-11-26 8:02 ` Christoph Hellwig
2018-11-28 8:55 ` Nicolas Boichat
2018-11-28 8:55 ` Nicolas Boichat
2018-11-28 8:55 ` Nicolas Boichat
2018-12-04 9:37 ` Nicolas Boichat
2018-12-04 9:37 ` Nicolas Boichat
2018-12-04 14:35 ` Vlastimil Babka
2018-12-04 14:35 ` Vlastimil Babka
2018-12-04 14:35 ` Vlastimil Babka
2018-12-05 2:04 ` Nicolas Boichat
2018-12-05 2:04 ` Nicolas Boichat
2018-12-05 2:04 ` Nicolas Boichat
2018-12-05 5:51 ` Nicolas Boichat
2018-12-05 5:51 ` Nicolas Boichat
2018-12-05 5:51 ` Nicolas Boichat
2018-12-05 14:41 ` Will Deacon
2018-12-05 14:41 ` Will Deacon
2018-12-05 14:41 ` Will Deacon
2018-12-04 16:28 ` Will Deacon
2018-12-04 16:28 ` Will Deacon
2018-12-04 16:28 ` Will Deacon
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