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 you

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 cl

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 we

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 blo

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: > > > https://lore.kernel.org/linux-fsdevel/yrtnlperhf

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 pl

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 Jane

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 range,

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 of

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 cl

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 I