From: Hillf Danton <hdanton@sina.com>
To: David Rientjes <rientjes@google.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>,
"Singh, Brijesh" <brijesh.singh@amd.com>,
"Grimm, Jon" <jon.grimm@amd.com>,
linux <linux-kernel@vger.kernel.org>,
iommu <iommu@lists.linux-foundation.org>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [rfc v2 3/6] dma-pool: dynamically expanding atomic pools
Date: Fri, 10 Apr 2020 22:55:20 +0800 [thread overview]
Message-ID: <20200410145520.17864-1-hdanton@sina.com> (raw)
In-Reply-To: <alpine.DEB.2.21.2004081418490.19661@chino.kir.corp.google.com>
On Wed, 8 Apr 2020 14:21:06 -0700 (PDT) David Rientjes wrote:
>
> When an atomic pool becomes fully depleted because it is now relied upon
> for all non-blocking allocations through the DMA API, allow background
> expansion of each pool by a kworker.
>
> When an atomic pool has less than the default size of memory left, kick
> off a kworker to dynamically expand the pool in the background. The pool
> is doubled in size, up to MAX_ORDER-1. If memory cannot be allocated at
> the requested order, smaller allocation(s) are attempted.
>
What is proposed looks like a path of single lane without how to
dynamically shrink the pool taken into account. Thus the risk may
rise in corner cases where pools are over-expanded in long run
after one-off peak allocation requests.
Is it worth the complexity of expander + shrinker at the first place?
> This allows the default size to be kept quite low when one or more of the
> atomic pools is not used.
>
> This also allows __dma_atomic_pool_init to return a pointer to the pool
> to make initialization cleaner.
>
> Also switch over some node ids to the more appropriate NUMA_NO_NODE.
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next prev parent reply other threads:[~2020-04-10 15:15 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-01 1:54 [rfc] dma-mapping: preallocate unencrypted DMA atomic pool David Rientjes via iommu
2020-01-06 17:34 ` Robin Murphy
2020-01-07 10:54 ` Christoph Hellwig
2020-01-07 19:57 ` David Rientjes via iommu
2020-01-09 14:31 ` Christoph Hellwig
2020-01-09 18:58 ` David Rientjes via iommu
2020-01-17 15:28 ` Tom Lendacky
2020-02-28 9:27 ` David Rientjes via iommu
2020-03-02 0:05 ` [rfc 0/6] unencrypted atomic DMA pools with dynamic expansion David Rientjes via iommu
2020-03-02 0:05 ` [rfc 1/6] dma-mapping: pass device to atomic allocation functions David Rientjes via iommu
2020-03-02 0:05 ` [rfc 2/6] dma-remap: add additional atomic pools to map to gfp mask David Rientjes via iommu
2020-03-05 15:42 ` Christoph Hellwig
2020-03-02 0:05 ` [rfc 3/6] dma-remap: wire up the atomic pools depending on " David Rientjes via iommu
2020-03-05 15:43 ` Christoph Hellwig
2020-03-02 0:05 ` [rfc 4/6] dma-remap: dynamically expanding atomic pools David Rientjes via iommu
2020-03-03 22:29 ` David Rientjes via iommu
2020-03-02 0:05 ` [rfc 5/6] dma-direct: atomic allocations must come from unencrypted pools David Rientjes via iommu
2020-03-05 15:44 ` Christoph Hellwig
2020-03-07 0:36 ` David Rientjes via iommu
2020-03-10 18:47 ` Christoph Hellwig
2020-03-02 0:05 ` [rfc 6/6] dma-remap: double the default DMA coherent pool size David Rientjes via iommu
2020-03-05 15:45 ` Christoph Hellwig
2020-04-08 21:21 ` [rfc v2 0/6] unencrypted atomic DMA pools with dynamic expansion David Rientjes via iommu
2020-04-08 21:21 ` [rfc v2 1/6] dma-remap: separate DMA atomic pools from direct remap code David Rientjes via iommu
2020-04-14 6:35 ` Christoph Hellwig
2020-04-08 21:21 ` [rfc v2 2/6] dma-pool: add additional coherent pools to map to gfp mask David Rientjes via iommu
2020-04-08 21:21 ` [rfc v2 3/6] dma-pool: dynamically expanding atomic pools David Rientjes via iommu
2020-04-08 21:21 ` [rfc v2 4/6] dma-direct: atomic allocations must come from atomic coherent pools David Rientjes via iommu
2020-04-09 21:24 ` Tom Lendacky
2020-04-14 19:18 ` David Rientjes via iommu
2020-04-14 6:43 ` Christoph Hellwig
2020-04-14 19:20 ` David Rientjes via iommu
2020-04-08 21:21 ` [rfc v2 5/6] x86/mm: unencrypted non-blocking DMA allocations use " David Rientjes via iommu
2020-04-08 21:21 ` [rfc v2 6/6] dma-pool: scale the default DMA coherent pool size with memory capacity David Rientjes via iommu
2020-04-10 14:55 ` Hillf Danton [this message]
2020-04-10 19:37 ` [rfc v2 3/6] dma-pool: dynamically expanding atomic pools David Rientjes via iommu
2020-04-14 6:44 ` Christoph Hellwig
2020-04-14 19:23 ` David Rientjes via iommu
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