From: Andy Lutomirski <luto@amacapital.net>
To: Andrew Morton <akpm@linux-foundation.org>,
Matthew Wilcox <willy@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v10 00/21] Support ext4 on NV-DIMMs
Date: Wed, 27 Aug 2014 18:30:27 -0700 [thread overview]
Message-ID: <53FE8633.10305@amacapital.net> (raw)
In-Reply-To: <20140827144622.ed81195a1d94799bb57a3207@linux-foundation.org>
On 08/27/2014 02:46 PM, Andrew Morton wrote:
> I assume (because I wasn't told!) that there are two objectives here:
>
> 1) reduce memory consumption by not maintaining pagecache and
> 2) reduce CPU cost by avoiding the double-copies.
>
> These things are pretty easily quantified. And really they must be
> quantified as part of the developer testing, because if you find
> they've worsened then holy cow, what went wrong.
>
There are two more huge ones:
3) Writes via mmap are immediately durable (or at least they're durable
after a *very* lightweight flush).
4) No page faults ever once a page is writable (I hope -- I'm not sure
whether this series actually achieves that goal).
A note on #3: there is ongoing work to enable write-through memory for
things like this. Once that's done, then writes via mmap might actually
be synchronously durable, depending on chipset details.
--Andy
WARNING: multiple messages have this Message-ID (diff)
From: Andy Lutomirski <luto@amacapital.net>
To: Andrew Morton <akpm@linux-foundation.org>,
Matthew Wilcox <willy@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v10 00/21] Support ext4 on NV-DIMMs
Date: Wed, 27 Aug 2014 18:30:27 -0700 [thread overview]
Message-ID: <53FE8633.10305@amacapital.net> (raw)
In-Reply-To: <20140827144622.ed81195a1d94799bb57a3207@linux-foundation.org>
On 08/27/2014 02:46 PM, Andrew Morton wrote:
> I assume (because I wasn't told!) that there are two objectives here:
>
> 1) reduce memory consumption by not maintaining pagecache and
> 2) reduce CPU cost by avoiding the double-copies.
>
> These things are pretty easily quantified. And really they must be
> quantified as part of the developer testing, because if you find
> they've worsened then holy cow, what went wrong.
>
There are two more huge ones:
3) Writes via mmap are immediately durable (or at least they're durable
after a *very* lightweight flush).
4) No page faults ever once a page is writable (I hope -- I'm not sure
whether this series actually achieves that goal).
A note on #3: there is ongoing work to enable write-through memory for
things like this. Once that's done, then writes via mmap might actually
be synchronously durable, depending on chipset details.
--Andy
--
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:[~2014-08-28 1:30 UTC|newest]
Thread overview: 104+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-27 3:45 [PATCH v10 00/21] Support ext4 on NV-DIMMs Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-08-27 3:45 ` [PATCH v10 01/21] axonram: Fix bug in direct_access Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-08-27 3:45 ` [PATCH v10 02/21] Change direct_access calling convention Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-08-27 3:45 ` [PATCH v10 03/21] Fix XIP fault vs truncate race Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-08-27 3:45 ` [PATCH v10 04/21] Allow page fault handlers to perform the COW Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-08-27 3:45 ` [PATCH v10 05/21] Introduce IS_DAX(inode) Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-08-27 3:45 ` [PATCH v10 06/21] Add copy_to_iter(), copy_from_iter() and iov_iter_zero() Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-08-27 3:45 ` [PATCH v10 07/21] Replace XIP read and write with DAX I/O Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-09-14 14:11 ` Boaz Harrosh
2014-09-14 14:11 ` Boaz Harrosh
2014-08-27 3:45 ` [PATCH v10 08/21] Replace ext2_clear_xip_target with dax_clear_blocks Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-08-27 3:45 ` [PATCH v10 09/21] Replace the XIP page fault handler with the DAX page fault handler Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-09-03 7:47 ` Dave Chinner
2014-09-03 7:47 ` Dave Chinner
2014-09-10 15:23 ` Matthew Wilcox
2014-09-10 15:23 ` Matthew Wilcox
2014-09-11 3:09 ` Dave Chinner
2014-09-11 3:09 ` Dave Chinner
2014-09-24 15:43 ` Matthew Wilcox
2014-09-24 15:43 ` Matthew Wilcox
2014-09-25 1:01 ` Dave Chinner
2014-09-25 1:01 ` Dave Chinner
2014-08-27 3:45 ` [PATCH v10 10/21] Replace xip_truncate_page with dax_truncate_page Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-08-27 3:45 ` [PATCH v10 11/21] Replace XIP documentation with DAX documentation Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-08-27 3:45 ` [PATCH v10 12/21] Remove get_xip_mem Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-08-27 3:45 ` [PATCH v10 13/21] ext2: Remove ext2_xip_verify_sb() Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-08-27 3:45 ` [PATCH v10 14/21] ext2: Remove ext2_use_xip Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-08-27 3:45 ` [PATCH v10 15/21] ext2: Remove xip.c and xip.h Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-08-27 3:45 ` [PATCH v10 16/21] Remove CONFIG_EXT2_FS_XIP and rename CONFIG_FS_XIP to CONFIG_FS_DAX Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-08-27 3:45 ` [PATCH v10 17/21] ext2: Remove ext2_aops_xip Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-08-27 3:45 ` [PATCH v10 18/21] Get rid of most mentions of XIP in ext2 Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-08-27 3:45 ` [PATCH v10 19/21] xip: Add xip_zero_page_range Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-09-03 9:21 ` Dave Chinner
2014-09-03 9:21 ` Dave Chinner
2014-09-04 21:08 ` Matthew Wilcox
2014-09-04 21:08 ` Matthew Wilcox
2014-09-04 21:36 ` Theodore Ts'o
2014-09-04 21:36 ` Theodore Ts'o
2014-09-08 18:59 ` Matthew Wilcox
2014-09-08 18:59 ` Matthew Wilcox
2014-08-27 3:45 ` [PATCH v10 20/21] ext4: Add DAX functionality Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-09-03 11:13 ` Dave Chinner
2014-09-03 11:13 ` Dave Chinner
2014-09-10 16:49 ` Boaz Harrosh
2014-09-10 16:49 ` Boaz Harrosh
2014-09-11 4:38 ` Dave Chinner
2014-09-11 4:38 ` Dave Chinner
2014-09-14 12:25 ` Boaz Harrosh
2014-09-14 12:25 ` Boaz Harrosh
2014-09-15 6:15 ` Dave Chinner
2014-09-15 6:15 ` Dave Chinner
2014-09-15 9:41 ` Boaz Harrosh
2014-09-15 9:41 ` Boaz Harrosh
2014-08-27 3:45 ` [PATCH v10 21/21] brd: Rename XIP to DAX Matthew Wilcox
2014-08-27 3:45 ` Matthew Wilcox
2014-08-27 20:06 ` [PATCH v10 00/21] Support ext4 on NV-DIMMs Andrew Morton
2014-08-27 20:06 ` Andrew Morton
2014-08-27 21:12 ` Matthew Wilcox
2014-08-27 21:12 ` Matthew Wilcox
2014-08-27 21:46 ` Andrew Morton
2014-08-27 21:46 ` Andrew Morton
2014-08-28 1:30 ` Andy Lutomirski [this message]
2014-08-28 1:30 ` Andy Lutomirski
2014-08-28 16:50 ` Matthew Wilcox
2014-08-28 16:50 ` Matthew Wilcox
2014-08-28 15:45 ` Matthew Wilcox
2014-08-28 15:45 ` Matthew Wilcox
2014-08-27 21:22 ` Christoph Lameter
2014-08-27 21:22 ` Christoph Lameter
2014-08-27 21:30 ` Andrew Morton
2014-08-27 21:30 ` Andrew Morton
2014-08-27 23:04 ` One Thousand Gnomes
2014-08-27 23:04 ` One Thousand Gnomes
2014-08-28 7:17 ` Dave Chinner
2014-08-28 7:17 ` Dave Chinner
2014-08-30 23:11 ` Christian Stroetmann
2014-08-30 23:11 ` Christian Stroetmann
2014-08-28 8:08 ` Boaz Harrosh
2014-08-28 8:08 ` Boaz Harrosh
2014-08-28 22:09 ` Zwisler, Ross
2014-08-28 22:09 ` Zwisler, Ross
2014-09-03 12:05 ` [PATCH 1/1] xfs: add DAX support Dave Chinner
2014-09-03 12:05 ` Dave Chinner
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=53FE8633.10305@amacapital.net \
--to=luto@amacapital.net \
--cc=akpm@linux-foundation.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=matthew.r.wilcox@intel.com \
--cc=willy@linux.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.