Re: [PATCH 0/3] dax: clear poison on the fly along pwrite

2021-09-23 Thread Dan Williams
On Thu, Sep 23, 2021 at 1:56 PM Jane Chu wrote: [..] > > This (AFAICT) has already been done for dax_zero_page_range, so I sense > > that Dan is trying to save you a bunch of code plumbing work by nudging > > you towards doing s/dax_clear_poison/dax_zero_page_range/ to this series > > and then

Re: [PATCH 0/3] dax: clear poison on the fly along pwrite

2021-09-23 Thread Jane Chu
On 9/15/2021 9:15 AM, Darrick J. Wong wrote: On Wed, Sep 15, 2021 at 12:22:05AM -0700, Jane Chu wrote: Hi, Dan, On 9/14/2021 9:44 PM, Dan Williams wrote: On Tue, Sep 14, 2021 at 4:32 PM Jane Chu wrote: If pwrite(2) encounters poison in a pmem range, it fails with EIO. This is unecessary if

Re: [PATCH 0/3] dax: clear poison on the fly along pwrite

2021-09-23 Thread Jane Chu
On 9/15/2021 1:27 PM, Dan Williams wrote: I'm also thinking about the MOVEDIR64B instruction and how it might be used to clear poison on the fly with a single 'store'. Of course, that means we need to figure out how to narrow down the error blast radius first. It turns out the MOVDIR64B error

Re: [PATCH 0/3] dax: clear poison on the fly along pwrite

2021-09-17 Thread Darrick J. Wong
On Fri, Sep 17, 2021 at 01:21:25PM -0700, Dan Williams wrote: > On Fri, Sep 17, 2021 at 8:27 AM Darrick J. Wong wrote: > > > > On Fri, Sep 17, 2021 at 01:53:33PM +0100, Christoph Hellwig wrote: > > > On Thu, Sep 16, 2021 at 11:40:28AM -0700, Dan Williams wrote: > > > > > That was my gut feeling.

Re: [PATCH 0/3] dax: clear poison on the fly along pwrite

2021-09-17 Thread Dan Williams
On Fri, Sep 17, 2021 at 8:27 AM Darrick J. Wong wrote: > > On Fri, Sep 17, 2021 at 01:53:33PM +0100, Christoph Hellwig wrote: > > On Thu, Sep 16, 2021 at 11:40:28AM -0700, Dan Williams wrote: > > > > That was my gut feeling. If everyone feels 100% comfortable with > > > > zeroingas the mechanism

Re: [PATCH 0/3] dax: clear poison on the fly along pwrite

2021-09-17 Thread Dan Williams
On Fri, Sep 17, 2021 at 5:57 AM Christoph Hellwig wrote: > > On Thu, Sep 16, 2021 at 11:40:28AM -0700, Dan Williams wrote: > > > That was my gut feeling. If everyone feels 100% comfortable with > > > zeroingas the mechanism to clear poisoning I'll cave in. The most > > > important bit is that

Re: [PATCH 0/3] dax: clear poison on the fly along pwrite

2021-09-17 Thread Darrick J. Wong
On Fri, Sep 17, 2021 at 01:53:33PM +0100, Christoph Hellwig wrote: > On Thu, Sep 16, 2021 at 11:40:28AM -0700, Dan Williams wrote: > > > That was my gut feeling. If everyone feels 100% comfortable with > > > zeroingas the mechanism to clear poisoning I'll cave in. The most > > > important bit is

Re: [PATCH 0/3] dax: clear poison on the fly along pwrite

2021-09-17 Thread Christoph Hellwig
On Thu, Sep 16, 2021 at 11:40:28AM -0700, Dan Williams wrote: > > That was my gut feeling. If everyone feels 100% comfortable with > > zeroingas the mechanism to clear poisoning I'll cave in. The most > > important bit is that we do that through a dedicated DAX path instead > > of abusing the

Re: [PATCH 0/3] dax: clear poison on the fly along pwrite

2021-09-16 Thread Dan Williams
On Thu, Sep 16, 2021 at 12:12 AM Christoph Hellwig wrote: > > On Wed, Sep 15, 2021 at 01:27:47PM -0700, Dan Williams wrote: > > > Yeah, Christoph suggested that we make the clearing operation explicit > > > in a related thread a few weeks ago: > > >

Re: [PATCH 0/3] dax: clear poison on the fly along pwrite

2021-09-16 Thread Christoph Hellwig
On Wed, Sep 15, 2021 at 01:27:47PM -0700, Dan Williams wrote: > > Yeah, Christoph suggested that we make the clearing operation explicit > > in a related thread a few weeks ago: > > https://lore.kernel.org/linux-fsdevel/yrtnlperhfmz2...@infradead.org/ > > That seemed to be tied to a proposal to

Re: [PATCH 0/3] dax: clear poison on the fly along pwrite

2021-09-15 Thread Darrick J. Wong
On Wed, Sep 15, 2021 at 01:27:47PM -0700, Dan Williams wrote: > On Wed, Sep 15, 2021 at 9:15 AM Darrick J. Wong wrote: > > > > On Wed, Sep 15, 2021 at 12:22:05AM -0700, Jane Chu wrote: > > > Hi, Dan, > > > > > > On 9/14/2021 9:44 PM, Dan Williams wrote: > > > > On Tue, Sep 14, 2021 at 4:32 PM

Re: [PATCH 0/3] dax: clear poison on the fly along pwrite

2021-09-15 Thread Dan Williams
On Wed, Sep 15, 2021 at 9:15 AM Darrick J. Wong wrote: > > On Wed, Sep 15, 2021 at 12:22:05AM -0700, Jane Chu wrote: > > Hi, Dan, > > > > On 9/14/2021 9:44 PM, Dan Williams wrote: > > > On Tue, Sep 14, 2021 at 4:32 PM Jane Chu wrote: > > > > > > > > If pwrite(2) encounters poison in a pmem

Re: [PATCH 0/3] dax: clear poison on the fly along pwrite

2021-09-15 Thread Darrick J. Wong
On Wed, Sep 15, 2021 at 12:22:05AM -0700, Jane Chu wrote: > Hi, Dan, > > On 9/14/2021 9:44 PM, Dan Williams wrote: > > On Tue, Sep 14, 2021 at 4:32 PM Jane Chu wrote: > > > > > > If pwrite(2) encounters poison in a pmem range, it fails with EIO. > > > This is unecessary if hardware is capable

Re: [PATCH 0/3] dax: clear poison on the fly along pwrite

2021-09-15 Thread Jane Chu
Hi, Dan, On 9/14/2021 9:44 PM, Dan Williams wrote: On Tue, Sep 14, 2021 at 4:32 PM Jane Chu wrote: If pwrite(2) encounters poison in a pmem range, it fails with EIO. This is unecessary if hardware is capable of clearing the poison. Though not all dax backend hardware has the capability of

Re: [PATCH 0/3] dax: clear poison on the fly along pwrite

2021-09-14 Thread Dan Williams
On Tue, Sep 14, 2021 at 4:32 PM Jane Chu wrote: > > If pwrite(2) encounters poison in a pmem range, it fails with EIO. > This is unecessary if hardware is capable of clearing the poison. > > Though not all dax backend hardware has the capability of clearing > poison on the fly, but dax backed by

[PATCH 0/3] dax: clear poison on the fly along pwrite

2021-09-14 Thread Jane Chu
If pwrite(2) encounters poison in a pmem range, it fails with EIO. This is unecessary if hardware is capable of clearing the poison. Though not all dax backend hardware has the capability of clearing poison on the fly, but dax backed by Intel DCPMEM has such capability, and it's desirable to,