From: Christoph Hellwig <hch@lst.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Christoph Hellwig <hch@lst.de>,
Andrew Morton <akpm@linux-foundation.org>,
Jan Kara <jack@suse.cz>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-xfs@vger.kernel.org, Linux MM <linux-mm@kvack.org>,
Jeff Moyer <jmoyer@redhat.com>, Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Ross Zwisler <ross.zwisler@linux.intel.com>,
Gerald Schaefer <gerald.schaefer@de.ibm.com>
Subject: Re: [PATCH v3 02/13] dax: require 'struct page' for filesystem dax
Date: Fri, 20 Oct 2017 18:29:33 +0200 [thread overview]
Message-ID: <20171020162933.GA26320@lst.de> (raw)
In-Reply-To: <CAPcyv4hA1nrhDf=DA6_j7s7ezGOBhvEVZ8cu81DNui_p3bhhaA@mail.gmail.com>
On Fri, Oct 20, 2017 at 08:23:02AM -0700, Dan Williams wrote:
> Yes, however it seems these drivers / platforms have been living with
> the lack of struct page for a long time. So they either don't use DAX,
> or they have a constrained use case that never triggers
> get_user_pages(). If it is the latter then they could introduce a new
> configuration option that bypasses the pfn_t_devmap() check in
> bdev_dax_supported() and fix up the get_user_pages() paths to fail.
> So, I'd like to understand how these drivers have been using DAX
> support without struct page to see if we need a workaround or we can
> go ahead delete this support. If the usage is limited to
> execute-in-place perhaps we can do a constrained ->direct_access() for
> just that case.
For axonram I doubt anyone is using it any more - it was a very for
the IBM Cell blades, which were produceѕ in a rather limited number.
And Cell basically seems to be dead as far as I can tell.
For S/390 Martin might be able to help out what the status of xpram
in general and DAX support in particular is.
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next prev parent reply other threads:[~2017-10-20 16:29 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-20 2:38 [PATCH v3 00/13] dax: fix dma vs truncate and remove 'page-less' support Dan Williams
2017-10-20 2:39 ` [PATCH v3 01/13] dax: quiet bdev_dax_supported() Dan Williams
2017-10-20 2:39 ` [PATCH v3 02/13] dax: require 'struct page' for filesystem dax Dan Williams
2017-10-20 7:57 ` Christoph Hellwig
2017-10-20 15:23 ` Dan Williams
2017-10-20 16:29 ` Christoph Hellwig [this message]
2017-10-20 22:29 ` Dan Williams
2017-10-21 3:20 ` Matthew Wilcox
2017-10-21 4:16 ` Dan Williams
2017-10-21 8:15 ` Christoph Hellwig
2017-10-23 5:18 ` Martin Schwidefsky
2017-10-23 8:55 ` Dan Williams
2017-10-23 10:44 ` Martin Schwidefsky
2017-10-23 11:20 ` Dan Williams
2017-10-20 2:39 ` [PATCH v3 03/13] dax: stop using VM_MIXEDMAP for dax Dan Williams
2017-10-20 2:39 ` [PATCH v3 04/13] dax: stop using VM_HUGEPAGE " Dan Williams
2017-10-20 2:39 ` [PATCH v3 05/13] dax: stop requiring a live device for dax_flush() Dan Williams
2017-10-20 2:39 ` [PATCH v3 06/13] dax: store pfns in the radix Dan Williams
2017-10-20 2:39 ` [PATCH v3 07/13] dax: warn if dma collides with truncate Dan Williams
2017-10-20 2:39 ` [PATCH v3 08/13] tools/testing/nvdimm: add 'bio_delay' mechanism Dan Williams
2017-10-20 2:39 ` [PATCH v3 09/13] IB/core: disable memory registration of fileystem-dax vmas Dan Williams
2017-10-20 2:39 ` [PATCH v3 10/13] mm: disable get_user_pages_fast() for dax Dan Williams
2017-10-20 2:39 ` [PATCH v3 11/13] fs: use smp_load_acquire in break_{layout,lease} Dan Williams
2017-10-20 12:39 ` Jeffrey Layton
2017-10-20 2:40 ` [PATCH v3 12/13] dax: handle truncate of dma-busy pages Dan Williams
2017-10-20 13:05 ` Jeff Layton
2017-10-20 15:42 ` Dan Williams
2017-10-20 16:32 ` Christoph Hellwig
2017-10-20 17:27 ` Dan Williams
2017-10-20 20:36 ` Brian Foster
2017-10-21 8:11 ` Christoph Hellwig
2017-10-20 2:40 ` [PATCH v3 13/13] xfs: wire up FL_ALLOCATED support Dan Williams
2017-10-20 7:47 ` [PATCH v3 00/13] dax: fix dma vs truncate and remove 'page-less' support Christoph Hellwig
2017-10-20 9:31 ` Christoph Hellwig
2017-10-26 10:58 ` Jan Kara
2017-10-26 23:51 ` Williams, Dan J
2017-10-27 6:48 ` Dave Chinner
2017-10-27 11:42 ` Dan Williams
2017-10-29 21:52 ` Dave Chinner
2017-10-27 6:45 ` Christoph Hellwig
2017-10-29 23:46 ` Dan Williams
2017-10-30 2:00 ` Dave Chinner
2017-10-30 8:38 ` Jan Kara
2017-10-30 11:20 ` Dave Chinner
2017-10-30 17:51 ` Dan Williams
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