From: Christoph Hellwig <hch@lst.de>
To: Boaz Harrosh <boaz@plexistor.com>
Cc: Dan Williams <dan.j.williams@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Jens Axboe <axboe@kernel.dk>, Rik van Riel <riel@redhat.com>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
Linux MM <linux-mm@kvack.org>, Mel Gorman <mgorman@suse.de>,
"torvalds@linux-foundation.org" <torvalds@linux-foundation.org>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v5 2/5] allow mapping page-less memremaped areas into KVA
Date: Thu, 13 Aug 2015 16:41:32 +0200 [thread overview]
Message-ID: <20150813144132.GC17375@lst.de> (raw)
In-Reply-To: <55CC9A5A.1020209@plexistor.com>
On Thu, Aug 13, 2015 at 04:23:38PM +0300, Boaz Harrosh wrote:
> > DAX as is is races against pmem unbind. A synchronization cost must
> > be paid somewhere to make sure the memremap() mapping is still valid.
>
> Sorry for being so slow, is what I asked. what is exactly "pmem unbind" ?
>
> Currently in my 4.1 Kernel the ioremap is done on modprobe time and
> released modprobe --remove time. the --remove can not happen with a mounted
> FS dax or not. So what is exactly "pmem unbind". And if there is a new knob
> then make it refuse with a raised refcount.
Surprise removal of a PCIe card which is mapped to provide non-volatile
memory for example. Or memory hot swap.
next prev parent reply other threads:[~2015-08-13 14:41 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-13 3:00 [PATCH v5 0/5] introduce __pfn_t for unmapped pfn I/O and DAX lifetime Dan Williams
2015-08-13 3:01 ` [PATCH v5 1/5] mm: move __phys_to_pfn and __pfn_to_phys to asm/generic/memory_model.h Dan Williams
2015-08-13 3:01 ` [PATCH v5 2/5] allow mapping page-less memremaped areas into KVA Dan Williams
2015-08-13 5:58 ` Boaz Harrosh
2015-08-13 12:57 ` Dan Williams
2015-08-13 13:23 ` Boaz Harrosh
2015-08-13 14:41 ` Christoph Hellwig [this message]
2015-08-13 15:01 ` Boaz Harrosh
2015-08-13 14:37 ` Christoph Hellwig
2015-08-13 14:48 ` Boaz Harrosh
2015-08-13 15:29 ` Boaz Harrosh
2015-08-13 17:37 ` Dave Hansen
2015-08-13 17:35 ` Matthew Wilcox
2015-08-13 18:15 ` Dan Williams
2015-08-13 3:01 ` [PATCH v5 3/5] dax: drop size parameter to ->direct_access() Dan Williams
2015-08-13 3:01 ` [PATCH v5 4/5] dax: fix mapping lifetime handling, convert to __pfn_t + kmap_atomic_pfn_t() Dan Williams
2015-08-13 6:26 ` Boaz Harrosh
2015-08-13 15:21 ` Dan Williams
2015-08-13 16:34 ` Boaz Harrosh
2015-08-13 18:51 ` Dan Williams
2015-08-13 3:01 ` [PATCH v5 5/5] scatterlist: convert to __pfn_t Dan Williams
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