Re: [PATCH v8 1/1] f2fs: dax: implement direct access

On Wed, Jul 26, 2017 at 1:11 PM, Christoph Hellwig wrote: > On Wed, Jul 26, 2017 at 12:16:11PM -0700, Dan Williams wrote: >> Silently turn on DAX if HMAT says its ok? > > Yes, absolutely. I want my system to do the right thing by default, > and if HMAT says bypassing the page

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

On Wed, Jul 26, 2017 at 1:11 PM, Christoph Hellwig wrote: > On Wed, Jul 26, 2017 at 12:16:11PM -0700, Dan Williams wrote: >> Silently turn on DAX if HMAT says its ok? > > Yes, absolutely. I want my system to do the right thing by default, > and if HMAT says bypassing the page cache is a clear

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

On Wed, Jul 26, 2017 at 12:16:11PM -0700, Dan Williams wrote: > Silently turn on DAX if HMAT says its ok? Yes, absolutely. I want my system to do the right thing by default, and if HMAT says bypassing the page cache is a clear advatange it should be the default. > I think we would instead >

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

On Wed, Jul 26, 2017 at 12:16:11PM -0700, Dan Williams wrote: > Silently turn on DAX if HMAT says its ok? Yes, absolutely. I want my system to do the right thing by default, and if HMAT says bypassing the page cache is a clear advatange it should be the default. > I think we would instead >

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

On Wed, Jul 26, 2017 at 10:20 AM, Christoph Hellwig wrote: > On Wed, Jul 26, 2017 at 10:11:08AM -0700, Dan Williams wrote: >> Until HMAT came along we had no data in the kernel how to pick a sane >> default, but we could now very easily make a "if pmem performance < >> dram,

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

On Wed, Jul 26, 2017 at 10:20 AM, Christoph Hellwig wrote: > On Wed, Jul 26, 2017 at 10:11:08AM -0700, Dan Williams wrote: >> Until HMAT came along we had no data in the kernel how to pick a sane >> default, but we could now very easily make a "if pmem performance < >> dram, disable dax by

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

On Wed, Jul 26, 2017 at 10:11:08AM -0700, Dan Williams wrote: > Until HMAT came along we had no data in the kernel how to pick a sane > default, but we could now very easily make a "if pmem performance < > dram, disable dax by default" policy in the kernel. I'd rather do it the other way around -

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

On Wed, Jul 26, 2017 at 10:11:08AM -0700, Dan Williams wrote: > Until HMAT came along we had no data in the kernel how to pick a sane > default, but we could now very easily make a "if pmem performance < > dram, disable dax by default" policy in the kernel. I'd rather do it the other way around -

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

On Wed, Jul 26, 2017 at 10:01 AM, Christoph Hellwig wrote: > On Wed, Jul 26, 2017 at 09:53:07AM -0700, Dan Williams wrote: >> It allows for opt-in for applications, or administrators of those >> applications, that know the type of access. > > That's BS. We need to provide the

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

On Wed, Jul 26, 2017 at 10:01 AM, Christoph Hellwig wrote: > On Wed, Jul 26, 2017 at 09:53:07AM -0700, Dan Williams wrote: >> It allows for opt-in for applications, or administrators of those >> applications, that know the type of access. > > That's BS. We need to provide the best possible way

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

On Wed, Jul 26, 2017 at 09:53:07AM -0700, Dan Williams wrote: > It allows for opt-in for applications, or administrators of those > applications, that know the type of access. That's BS. We need to provide the best possible way to access the media to an application. And whether that's DAX or

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

On Wed, Jul 26, 2017 at 09:53:07AM -0700, Dan Williams wrote: > It allows for opt-in for applications, or administrators of those > applications, that know the type of access. That's BS. We need to provide the best possible way to access the media to an application. And whether that's DAX or

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

On Wed, Jul 26, 2017 at 12:26 AM, Christoph Hellwig wrote: > On Tue, Jul 25, 2017 at 05:15:10PM -0700, Dan Williams wrote: >> We're in the process of walking back and potentially deprecating the >> use of the dax mount option for xfs and ext4 since dax can have >> negative

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

On Wed, Jul 26, 2017 at 12:26 AM, Christoph Hellwig wrote: > On Tue, Jul 25, 2017 at 05:15:10PM -0700, Dan Williams wrote: >> We're in the process of walking back and potentially deprecating the >> use of the dax mount option for xfs and ext4 since dax can have >> negative performance

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

On Tue, Jul 25, 2017 at 05:15:10PM -0700, Dan Williams wrote: > We're in the process of walking back and potentially deprecating the > use of the dax mount option for xfs and ext4 since dax can have > negative performance implications if page cache memory happens to be > faster than pmem. It

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

On Tue, Jul 25, 2017 at 05:15:10PM -0700, Dan Williams wrote: > We're in the process of walking back and potentially deprecating the > use of the dax mount option for xfs and ext4 since dax can have > negative performance implications if page cache memory happens to be > faster than pmem. It

RE: [PATCH v8 1/1] f2fs: dax: implement direct access

_inode_flags() Thanks, From: Jaegeuk Kim [jaeg...@kernel.org] Sent: Wednesday, July 26, 2017 10:16 To: Dan Williams Cc: sunqiuyang; Linux Kernel Mailing List; linux-fsdevel; linux-f2fs-de...@lists.sourceforge.net; linux-nvd...@lists.01.org Subject: Re: [PATCH v8 1/1] f2fs: dax: impl

RE: [PATCH v8 1/1] f2fs: dax: implement direct access

_inode_flags() Thanks, From: Jaegeuk Kim [jaeg...@kernel.org] Sent: Wednesday, July 26, 2017 10:16 To: Dan Williams Cc: sunqiuyang; Linux Kernel Mailing List; linux-fsdevel; linux-f2fs-de...@lists.sourceforge.net; linux-nvd...@lists.01.org Subject: Re: [PATCH v8 1/1] f2fs: dax: impl

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

Hi Dan, On 07/25, Dan Williams wrote: > [ adding linux-nvdimm ] > > On Thu, Jul 20, 2017 at 5:10 AM, sunqiuyang wrote: > > From: Qiuyang Sun > > > > This patch implements Direct Access (DAX) in F2FS, including: > > - a mount option to choose

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

Hi Dan, On 07/25, Dan Williams wrote: > [ adding linux-nvdimm ] > > On Thu, Jul 20, 2017 at 5:10 AM, sunqiuyang wrote: > > From: Qiuyang Sun > > > > This patch implements Direct Access (DAX) in F2FS, including: > > - a mount option to choose whether to enable DAX or not > > We're in the

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

[ adding linux-nvdimm ] On Thu, Jul 20, 2017 at 5:10 AM, sunqiuyang wrote: > From: Qiuyang Sun > > This patch implements Direct Access (DAX) in F2FS, including: > - a mount option to choose whether to enable DAX or not We're in the process of

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

[ adding linux-nvdimm ] On Thu, Jul 20, 2017 at 5:10 AM, sunqiuyang wrote: > From: Qiuyang Sun > > This patch implements Direct Access (DAX) in F2FS, including: > - a mount option to choose whether to enable DAX or not We're in the process of walking back and potentially deprecating the use

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

Hi Jaegeuk, Below is the error message I got from this testcase: --- write (Invalid argument) len 1024 dio [dax to nondax | both nodax] read (Bad address) len [4096 | 16777216 | 67108864] dio dax to nondax --- The write error is expected, as F2FS does not support unaligned direct IO (1024 B).

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

Hi Jaegeuk, Below is the error message I got from this testcase: --- write (Invalid argument) len 1024 dio [dax to nondax | both nodax] read (Bad address) len [4096 | 16777216 | 67108864] dio dax to nondax --- The write error is expected, as F2FS does not support unaligned direct IO (1024 B).

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

Hi Qiuyang, This fails xfstests/generic/413. Thanks, On 07/20, sunqiuyang wrote: > From: Qiuyang Sun > > This patch implements Direct Access (DAX) in F2FS, including: > - a mount option to choose whether to enable DAX or not > - read/write and mmap of regular files in

Re: [PATCH v8 1/1] f2fs: dax: implement direct access

Hi Qiuyang, This fails xfstests/generic/413. Thanks, On 07/20, sunqiuyang wrote: > From: Qiuyang Sun > > This patch implements Direct Access (DAX) in F2FS, including: > - a mount option to choose whether to enable DAX or not > - read/write and mmap of regular files in the DAX way > -