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From: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: <linux-cxl@vger.kernel.org>, Jason Gunthorpe <jgg@nvidia.com>,
	"Matthew Wilcox" <willy@infradead.org>,
	Christoph Hellwig <hch@lst.de>, <nvdimm@lists.linux.dev>,
	<linux-pci@vger.kernel.org>
Subject: Re: [PATCH v2 16/28] resource: Introduce alloc_free_mem_region()
Date: Wed, 20 Jul 2022 18:00:05 +0100	[thread overview]
Message-ID: <20220720180005.0000190d@Huawei.com> (raw)
In-Reply-To: <165784333333.1758207.13703329337805274043.stgit@dwillia2-xfh.jf.intel.com>

On Thu, 14 Jul 2022 17:02:13 -0700
Dan Williams <dan.j.williams@intel.com> wrote:

> The core of devm_request_free_mem_region() is a helper that searches for
> free space in iomem_resource and performs __request_region_locked() on
> the result of that search. The policy choices of the implementation
> conform to what CONFIG_DEVICE_PRIVATE users want which is memory that is
> immediately marked busy, and a preference to search for the first-fit
> free range in descending order from the top of the physical address
> space.
> 
> CXL has a need for a similar allocator, but with the following tweaks:
> 
> 1/ Search for free space in ascending order
> 
> 2/ Search for free space relative to a given CXL window
> 
> 3/ 'insert' rather than 'request' the new resource given downstream
>    drivers from the CXL Region driver (like the pmem or dax drivers) are
>    responsible for request_mem_region() when they activate the memory
>    range.
> 
> Rework __request_free_mem_region() into get_free_mem_region() which
> takes a set of GFR_* (Get Free Region) flags to control the allocation
> policy (ascending vs descending), and "busy" policy (insert_resource()
> vs request_region()).
> 
> As part of the consolidation of the legacy GFR_REQUEST_REGION case with
> the new default of just inserting a new resource into the free space
> some minor cleanups like not checking for NULL before calling
> devres_free() (which does its own check) is included.
> 
> Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
> Link: https://lore.kernel.org/linux-cxl/20220420143406.GY2120790@nvidia.com/
> Cc: Matthew Wilcox <willy@infradead.org>
> Cc: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Given you answered all my questions on v1, I'm fine with this.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

  reply	other threads:[~2022-07-20 17:00 UTC|newest]

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-15  0:00 [PATCH v2 00/28] CXL PMEM Region Provisioning Dan Williams
2022-07-15  0:00 ` [PATCH v2 01/28] Documentation/cxl: Use a double line break between entries Dan Williams
2022-07-20 13:26   ` Jonathan Cameron
2022-07-15  0:00 ` [PATCH v2 02/28] cxl/core: Define a 'struct cxl_switch_decoder' Dan Williams
2022-07-15  2:57   ` kernel test robot
2022-07-20 15:39   ` Jonathan Cameron
2022-07-15  0:00 ` [PATCH v2 03/28] cxl/acpi: Track CXL resources in iomem_resource Dan Williams
2022-07-15  5:23   ` Greg Kroah-Hartman
2022-07-20 16:03   ` Jonathan Cameron
2022-07-15  0:01 ` [PATCH v2 04/28] cxl/core: Define a 'struct cxl_root_decoder' Dan Williams
2022-07-20 16:07   ` Jonathan Cameron
2022-07-15  0:01 ` [PATCH v2 05/28] cxl/core: Define a 'struct cxl_endpoint_decoder' Dan Williams
2022-07-20 16:11   ` Jonathan Cameron
2022-07-15  0:01 ` [PATCH v2 06/28] cxl/hdm: Enumerate allocated DPA Dan Williams
2022-07-20 16:40   ` Jonathan Cameron
2022-07-21 15:29     ` Dan Williams
2022-07-15  0:01 ` [PATCH v2 07/28] cxl/hdm: Add 'mode' attribute to decoder objects Dan Williams
2022-07-15  0:01 ` [PATCH v2 08/28] cxl/hdm: Track next decoder to allocate Dan Williams
2022-07-20 16:45   ` Jonathan Cameron
2022-07-15  0:01 ` [PATCH v2 09/28] cxl/hdm: Add support for allocating DPA to an endpoint decoder Dan Williams
2022-07-20 16:51   ` Jonathan Cameron
2022-07-15  0:01 ` [PATCH v2 10/28] cxl/port: Record dport in endpoint references Dan Williams
2022-07-20 16:53   ` Jonathan Cameron
2022-07-15  0:01 ` [PATCH v2 11/28] cxl/port: Record parent dport when adding ports Dan Williams
2022-07-15  0:01 ` [PATCH v2 12/28] cxl/port: Move 'cxl_ep' references to an xarray per port Dan Williams
2022-07-15  0:01 ` [PATCH v2 13/28] cxl/port: Move dport tracking to an xarray Dan Williams
2022-07-20 16:56   ` Jonathan Cameron
2022-07-15  0:02 ` [PATCH v2 14/28] cxl/hdm: Add sysfs attributes for interleave ways + granularity Dan Williams
2022-07-20 16:58   ` Jonathan Cameron
2022-07-15  0:02 ` [PATCH v2 15/28] cxl/mem: Enumerate port targets before adding endpoints Dan Williams
2022-07-15  0:02 ` [PATCH v2 16/28] resource: Introduce alloc_free_mem_region() Dan Williams
2022-07-20 17:00   ` Jonathan Cameron [this message]
2022-07-21 16:10   ` Dan Williams
2022-07-21 16:10     ` Dan Williams
2022-07-21 16:10     ` [Nouveau] " Dan Williams
2022-09-06 13:25   ` Rogerio Alves
2022-07-15  0:02 ` [PATCH v2 17/28] cxl/region: Add region creation support Dan Williams
2022-07-20 17:16   ` Jonathan Cameron
2022-07-15  0:02 ` [PATCH v2 18/28] cxl/region: Add a 'uuid' attribute Dan Williams
2022-07-20 17:18   ` Jonathan Cameron
2022-07-15  0:02 ` [PATCH v2 19/28] cxl/region: Add interleave geometry attributes Dan Williams
2022-07-15  0:02 ` [PATCH v2 20/28] cxl/region: Allocate HPA capacity to regions Dan Williams
2022-07-20 17:20   ` Jonathan Cameron
2022-07-15  0:02 ` [PATCH v2 21/28] cxl/region: Enable the assignment of endpoint decoders " Dan Williams
2022-07-15  3:28   ` kernel test robot
2022-07-20 17:26   ` Jonathan Cameron
2022-07-20 19:05     ` Dan Williams
2022-07-15  0:02 ` [PATCH v2 22/28] cxl/acpi: Add a host-bridge index lookup mechanism Dan Williams
2022-07-15  0:02 ` [PATCH v2 23/28] cxl/region: Attach endpoint decoders Dan Williams
2022-07-20 17:29   ` Jonathan Cameron
2022-07-15  0:02 ` [PATCH v2 24/28] cxl/region: Program target lists Dan Williams
2022-07-20 17:41   ` Jonathan Cameron
2022-07-21 16:56     ` Dan Williams
2022-07-15  0:03 ` [PATCH v2 25/28] cxl/hdm: Commit decoder state to hardware Dan Williams
2022-07-20 17:44   ` Jonathan Cameron
2022-07-15  0:03 ` [PATCH v2 26/28] cxl/region: Add region driver boiler plate Dan Williams
2022-07-15  0:03 ` [PATCH v2 27/28] cxl/pmem: Fix offline_nvdimm_bus() to offline by bridge Dan Williams
2022-07-20 17:46   ` Jonathan Cameron
2022-07-15  0:03 ` [PATCH v2 28/28] cxl/region: Introduce cxl_pmem_region objects Dan Williams
2022-07-20 18:05   ` Jonathan Cameron
2022-07-20 18:12 ` [PATCH v2 00/28] CXL PMEM Region Provisioning Jonathan Cameron
2022-07-21 18:34   ` Dan Williams
2022-07-21 14:59 ` Jonathan Cameron
2022-07-21 16:29   ` Dan Williams
2022-07-21 17:22     ` Jonathan Cameron
2022-07-16 19:55 [PATCH v2 21/28] cxl/region: Enable the assignment of endpoint decoders to regions kernel test robot
2022-07-18 11:32 ` Dan Carpenter

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