From: Christoph Hellwig <hch@lst.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-nvdimm@lists.01.org, boaz@plexistor.com,
david@fromorbit.com, linux-kernel@vger.kernel.org, hch@lst.de,
linux-mm@kvack.org, hpa@zytor.com, ross.zwisler@linux.intel.com,
mingo@kernel.org
Subject: Re: [PATCH v2 9/9] devm_memremap_pages: protect against pmem device unbind
Date: Wed, 26 Aug 2015 14:46:49 +0200 [thread overview]
Message-ID: <20150826124649.GA8014@lst.de> (raw)
In-Reply-To: <20150826012813.8851.35482.stgit@dwillia2-desk3.amr.corp.intel.com>
On Tue, Aug 25, 2015 at 09:28:13PM -0400, Dan Williams wrote:
> Given that:
>
> 1/ device ->remove() can not be failed
>
> 2/ a pmem device may be unbound at any time
>
> 3/ we do not know what other parts of the kernel are actively using a
> 'struct page' from devm_memremap_pages()
>
> ...provide a facility for active usages of device memory to block pmem
> device unbind. With a percpu_ref it should be feasible to take a
> reference on a per-I/O or other high frequency basis.
Without a caller of get_page_map this is just adding dead code. I'd
suggest to group it in a series with that caller.
Also if the page_map gets exposed in a header the name is a bit too generic.
memremap_map maybe?
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WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-nvdimm@ml01.01.org, boaz@plexistor.com,
david@fromorbit.com, linux-kernel@vger.kernel.org, hch@lst.de,
linux-mm@kvack.org, hpa@zytor.com, ross.zwisler@linux.intel.com,
mingo@kernel.org
Subject: Re: [PATCH v2 9/9] devm_memremap_pages: protect against pmem device unbind
Date: Wed, 26 Aug 2015 14:46:49 +0200 [thread overview]
Message-ID: <20150826124649.GA8014@lst.de> (raw)
In-Reply-To: <20150826012813.8851.35482.stgit@dwillia2-desk3.amr.corp.intel.com>
On Tue, Aug 25, 2015 at 09:28:13PM -0400, Dan Williams wrote:
> Given that:
>
> 1/ device ->remove() can not be failed
>
> 2/ a pmem device may be unbound at any time
>
> 3/ we do not know what other parts of the kernel are actively using a
> 'struct page' from devm_memremap_pages()
>
> ...provide a facility for active usages of device memory to block pmem
> device unbind. With a percpu_ref it should be feasible to take a
> reference on a per-I/O or other high frequency basis.
Without a caller of get_page_map this is just adding dead code. I'd
suggest to group it in a series with that caller.
Also if the page_map gets exposed in a header the name is a bit too generic.
memremap_map maybe?
next prev parent reply other threads:[~2015-08-26 12:46 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-26 1:27 [PATCH v2 0/9] initial struct page support for pmem Dan Williams
2015-08-26 1:27 ` Dan Williams
2015-08-26 1:27 ` [PATCH v2 1/9] dax: drop size parameter to ->direct_access() Dan Williams
2015-08-26 1:27 ` Dan Williams
2015-08-26 1:27 ` [PATCH v2 2/9] mm: move __phys_to_pfn and __pfn_to_phys to asm/generic/memory_model.h Dan Williams
2015-08-26 1:27 ` Dan Williams
2015-09-18 23:42 ` Tyler Baker
2015-09-18 23:42 ` Tyler Baker
2015-09-18 23:59 ` Dan Williams
2015-09-18 23:59 ` Dan Williams
2015-09-19 6:49 ` Tyler Baker
2015-09-19 6:49 ` Tyler Baker
2015-09-29 19:21 ` Nicolas Pitre
2015-09-29 19:21 ` Nicolas Pitre
2015-09-29 19:36 ` Tyler Baker
2015-09-29 19:36 ` Tyler Baker
2015-09-29 19:36 ` Tyler Baker
2015-09-29 19:47 ` Nicolas Pitre
2015-09-29 19:47 ` Nicolas Pitre
2015-09-29 19:47 ` Nicolas Pitre
2015-08-26 1:27 ` [PATCH v2 3/9] mm: ZONE_DEVICE for "device memory" Dan Williams
2015-08-26 1:27 ` Dan Williams
2015-08-26 1:27 ` [PATCH v2 4/9] add devm_memremap_pages Dan Williams
2015-08-26 1:27 ` Dan Williams
2015-08-26 1:27 ` [PATCH v2 5/9] x86, pmem: push fallback handling to arch code Dan Williams
2015-08-26 1:27 ` Dan Williams
2015-08-26 12:41 ` Christoph Hellwig
2015-08-26 12:41 ` Christoph Hellwig
2015-08-26 21:34 ` Williams, Dan J
2015-08-26 21:34 ` Williams, Dan J
2015-08-27 7:33 ` hch
2015-08-27 7:33 ` hch
2015-08-28 20:22 ` Ross Zwisler
2015-08-28 20:22 ` Ross Zwisler
2015-08-28 21:41 ` Toshi Kani
2015-08-28 21:41 ` Toshi Kani
2015-08-28 21:47 ` Dan Williams
2015-08-28 21:47 ` Dan Williams
2015-08-28 21:48 ` Toshi Kani
2015-08-28 21:48 ` Toshi Kani
2015-08-29 4:04 ` Williams, Dan J
2015-08-29 4:04 ` Williams, Dan J
2015-08-29 13:57 ` hch
2015-08-29 13:57 ` hch
2015-08-26 1:27 ` [PATCH v2 6/9] libnvdimm, pfn: 'struct page' provider infrastructure Dan Williams
2015-08-26 1:27 ` Dan Williams
2015-08-26 1:28 ` [PATCH v2 7/9] libnvdimm, pmem: 'struct page' for pmem Dan Williams
2015-08-26 1:28 ` Dan Williams
2015-08-26 1:28 ` [PATCH v2 8/9] libnvdimm, pmem: direct map legacy pmem by default Dan Williams
2015-08-26 1:28 ` Dan Williams
2015-08-26 1:28 ` [PATCH v2 9/9] devm_memremap_pages: protect against pmem device unbind Dan Williams
2015-08-26 1:28 ` Dan Williams
2015-08-26 12:46 ` Christoph Hellwig [this message]
2015-08-26 12:46 ` Christoph Hellwig
2015-08-26 21:39 ` Williams, Dan J
2015-08-26 21:39 ` Williams, Dan J
2015-08-27 7:33 ` hch
2015-08-27 7:33 ` hch
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