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From: David Hildenbrand <david@redhat.com>
To: Jichao Zou <zoujc@motorola.com>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"minchan@kernel.org" <minchan@kernel.org>,
	"song.bao.hua@hisilicon.com" <song.bao.hua@hisilicon.com>,
	"hch@lst.de" <hch@lst.de>,
	"m.szyprowski@samsung.com" <m.szyprowski@samsung.com>,
	"robin.murphy@arm.com" <robin.murphy@arm.com>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	JianQi Yang <yangj@motorola.com>,
	Yanjune Tian <tianyje@motorola.com>
Subject: Re: An cma optimization patch is used for cma_[alloc|free].
Date: Fri, 13 Aug 2021 09:45:02 +0200	[thread overview]
Message-ID: <f5cd9fe6-3b62-eab8-1ff1-d3943d4bb85b@redhat.com> (raw)
In-Reply-To: <HK0PR03MB4177A44D9DAD3302251B0EC8D5FA9@HK0PR03MB4177.apcprd03.prod.outlook.com>

On 13.08.21 09:00, Jichao Zou wrote:
> Pre-allocate CMA memory that configured in device
> tree, this greatly improves the CMA memory
> allocation efficiency, cma_[alloc|free] is less
> than 1ms, old way is took a few ms to tens or
> hundreds ms.
> 

Please send patches as proper emails (man git-format-patch; man 
git-send-email).

What you propose is turning cma reservations into something comparable 
to permanent boottime allocations. From the POV of the buddy, the pages 
are always allocated and cannot be repurposed for e.g., movable 
allocations until *actually* allocated via CMA.

I don't think we want this behavior upstream.

-- 
Thanks,

David / dhildenb


WARNING: multiple messages have this Message-ID (diff)
From: David Hildenbrand <david@redhat.com>
To: Jichao Zou <zoujc@motorola.com>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"minchan@kernel.org" <minchan@kernel.org>,
	"song.bao.hua@hisilicon.com" <song.bao.hua@hisilicon.com>,
	"hch@lst.de" <hch@lst.de>,
	"m.szyprowski@samsung.com" <m.szyprowski@samsung.com>,
	"robin.murphy@arm.com" <robin.murphy@arm.com>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	JianQi Yang <yangj@motorola.com>,
	Yanjune Tian <tianyje@motorola.com>
Subject: Re: An cma optimization patch is used for cma_[alloc|free].
Date: Fri, 13 Aug 2021 09:45:02 +0200	[thread overview]
Message-ID: <f5cd9fe6-3b62-eab8-1ff1-d3943d4bb85b@redhat.com> (raw)
In-Reply-To: <HK0PR03MB4177A44D9DAD3302251B0EC8D5FA9@HK0PR03MB4177.apcprd03.prod.outlook.com>

On 13.08.21 09:00, Jichao Zou wrote:
> Pre-allocate CMA memory that configured in device
> tree, this greatly improves the CMA memory
> allocation efficiency, cma_[alloc|free] is less
> than 1ms, old way is took a few ms to tens or
> hundreds ms.
> 

Please send patches as proper emails (man git-format-patch; man 
git-send-email).

What you propose is turning cma reservations into something comparable 
to permanent boottime allocations. From the POV of the buddy, the pages 
are always allocated and cannot be repurposed for e.g., movable 
allocations until *actually* allocated via CMA.

I don't think we want this behavior upstream.

-- 
Thanks,

David / dhildenb

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  reply	other threads:[~2021-08-13  7:45 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-13  7:00 An cma optimization patch is used for cma_[alloc|free] Jichao Zou
2021-08-13  7:00 ` Jichao Zou
2021-08-13  7:45 ` David Hildenbrand [this message]
2021-08-13  7:45   ` David Hildenbrand
2021-08-13  8:27   ` 回复: [External]Re: " Jichao Zou
2021-08-13  8:27     ` Jichao Zou
2021-08-13  9:15     ` Robin Murphy
2021-08-13  9:15       ` Robin Murphy
2021-08-13  9:46       ` 回复: " Jichao Zou
2021-08-13  9:46         ` Jichao Zou
2021-08-13 10:08         ` Robin Murphy
2021-08-13 10:08           ` Robin Murphy
2021-08-13 11:26           ` 回复: " Jichao Zou
2021-08-13 11:26             ` Jichao Zou

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