From: Matthew Wilcox <willy@linux.intel.com>
To: Chris Brandt <Chris.Brandt@renesas.com>
Cc: "Wilcox, Matthew R" <matthew.r.wilcox@intel.com>,
Jared Hulbert <jaredeh@gmail.com>,
Linux FS Devel <linux-fsdevel@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Carsten Otte <cotte@de.ibm.com>
Subject: Re: [PATCH v12 10/20] dax: Replace XIP documentation with DAX documentation
Date: Fri, 22 Jan 2016 09:39:00 -0500 [thread overview]
Message-ID: <20160122143900.GE2948@linux.intel.com> (raw)
In-Reply-To: <HK2PR06MB05610F968A8B0E5E0E6BCDC98AC40@HK2PR06MB0561.apcprd06.prod.outlook.com>
On Fri, Jan 22, 2016 at 01:48:08PM +0000, Chris Brandt wrote:
> I believe the motivation for the new DAX code was being able to
> read/write data directly to specific physical memory. However, with
> the AXFS file system, XIP file mapping was mostly beneficial for direct
> access to executable code pages, not data. Code pages were XIP-ed, and
> data pages were copied to RAM as normal. This results in a significant
> reduction in system RAM, especially when used with an XIP_KERNEL. In
> some systems, most of your RAM is eaten up by lots of code pages from
> big bloated shared libraries, not R/W data. (of course I'm talking about
> smaller embedded system here)
OK, I can't construct a failure case for read-only usages. If you want
to put together a patch-set that re-enables DAX in a read-only way on
those architectures, I'm fine with that.
I think your time would be better spent fixing the read-write problems;
once we see persistent memory on the embedded platforms, we'll need that
code anyway.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2016-01-22 14:39 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-24 21:20 [PATCH v12 00/20] DAX: Page cache bypass for filesystems on memory storage Matthew Wilcox
2014-10-24 21:20 ` [PATCH v12 01/20] axonram: Fix bug in direct_access Matthew Wilcox
2014-10-24 21:20 ` [PATCH v12 02/20] block: Change direct_access calling convention Matthew Wilcox
2014-10-24 21:20 ` [PATCH v12 03/20] mm: Fix XIP fault vs truncate race Matthew Wilcox
2015-01-12 23:09 ` Andrew Morton
2015-01-13 18:50 ` Matthew Wilcox
2014-10-24 21:20 ` [PATCH v12 04/20] mm: Allow page fault handlers to perform the COW Matthew Wilcox
2015-01-12 23:09 ` Andrew Morton
2015-01-13 18:58 ` Matthew Wilcox
2015-02-05 9:16 ` Yigal Korman
2015-02-05 21:39 ` Matthew Wilcox
2015-02-08 11:48 ` Yigal Korman
2014-10-24 21:20 ` [PATCH v12 05/20] vfs,ext2: Introduce IS_DAX(inode) Matthew Wilcox
2014-10-24 21:20 ` [PATCH v12 06/20] dax,ext2: Replace XIP read and write with DAX I/O Matthew Wilcox
2015-01-12 23:09 ` Andrew Morton
2015-01-13 20:59 ` Matthew Wilcox
2014-10-24 21:20 ` [PATCH v12 07/20] dax,ext2: Replace ext2_clear_xip_target with dax_clear_blocks Matthew Wilcox
2015-01-12 23:09 ` Andrew Morton
2015-01-13 21:39 ` Matthew Wilcox
2014-10-24 21:20 ` [PATCH v12 08/20] dax,ext2: Replace the XIP page fault handler with the DAX page fault handler Matthew Wilcox
2015-01-12 23:09 ` Andrew Morton
2015-01-13 21:53 ` Matthew Wilcox
2015-01-13 22:47 ` Andrew Morton
2014-10-24 21:20 ` [PATCH v12 09/20] dax,ext2: Replace xip_truncate_page with dax_truncate_page Matthew Wilcox
2015-01-12 23:09 ` Andrew Morton
2015-01-13 21:55 ` Matthew Wilcox
2014-10-24 21:20 ` [PATCH v12 10/20] dax: Replace XIP documentation with DAX documentation Matthew Wilcox
2015-01-12 23:10 ` Andrew Morton
2016-01-21 18:38 ` Jared Hulbert
2016-01-22 13:07 ` Wilcox, Matthew R
2016-01-22 13:48 ` Chris Brandt
2016-01-22 14:39 ` Matthew Wilcox [this message]
2016-01-24 9:03 ` Jared Hulbert
2016-01-25 16:52 ` Matthew Wilcox
2016-01-25 21:18 ` Jared Hulbert
2016-01-27 19:51 ` Jared Hulbert
2014-10-24 21:20 ` [PATCH v12 11/20] vfs: Remove get_xip_mem Matthew Wilcox
2014-10-24 21:20 ` [PATCH v12 12/20] ext2: Remove ext2_xip_verify_sb() Matthew Wilcox
2014-10-24 21:20 ` [PATCH v12 13/20] ext2: Remove ext2_use_xip Matthew Wilcox
2014-10-24 21:20 ` [PATCH v12 14/20] ext2: Remove xip.c and xip.h Matthew Wilcox
2014-10-24 21:20 ` [PATCH v12 15/20] vfs,ext2: Remove CONFIG_EXT2_FS_XIP and rename CONFIG_FS_XIP to CONFIG_FS_DAX Matthew Wilcox
2014-10-24 21:20 ` [PATCH v12 16/20] ext2: Remove ext2_aops_xip Matthew Wilcox
2014-10-24 21:20 ` [PATCH v12 17/20] ext2: Get rid of most mentions of XIP in ext2 Matthew Wilcox
2014-10-24 21:20 ` [PATCH v12 18/20] dax: Add dax_zero_page_range Matthew Wilcox
2015-01-12 23:10 ` Andrew Morton
2015-01-12 23:20 ` Ross Zwisler
2014-10-24 21:20 ` [PATCH v12 19/20] ext4: Add DAX functionality Matthew Wilcox
2014-10-24 21:20 ` [PATCH v12 20/20] brd: Rename XIP to DAX Matthew Wilcox
2014-12-10 14:03 ` [PATCH v12 00/20] DAX: Page cache bypass for filesystems on memory storage Christoph Hellwig
2014-12-10 14:12 ` Matthew Wilcox
2014-12-10 14:28 ` Jeff Moyer
2014-12-10 20:53 ` Dave Chinner
2015-01-05 18:41 ` Christoph Hellwig
2015-01-06 8:47 ` Andrew Morton
2015-01-08 11:49 ` pread2/ pwrite2 Christoph Hellwig
2015-01-09 19:30 ` Steve French
2015-01-08 16:27 ` [PATCH v12 00/20] DAX: Page cache bypass for filesystems on memory storage Milosz Tanski
2015-01-08 16:28 ` Milosz Tanski
2015-01-08 17:36 ` Jeremy Allison
2015-01-12 14:47 ` Matthew Wilcox
2015-01-12 23:09 ` Andrew Morton
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160122143900.GE2948@linux.intel.com \
--to=willy@linux.intel.com \
--cc=Chris.Brandt@renesas.com \
--cc=akpm@linux-foundation.org \
--cc=cotte@de.ibm.com \
--cc=jaredeh@gmail.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=matthew.r.wilcox@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).