From: Dan Williams <dan.j.williams@intel.com>
To: Jeff Moyer <jmoyer@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
Oscar Salvador <osalvador@suse.de>, Qian Cai <cai@lca.pw>,
Andrew Morton <akpm@linux-foundation.org>,
Linux MM <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-nvdimm <linux-nvdimm@lists.01.org>
Subject: Re: [PATCH -next] mm/hotplug: skip bad PFNs from pfn_to_online_page()
Date: Fri, 14 Jun 2019 10:14:06 -0700 [thread overview]
Message-ID: <CAPcyv4iADcyPP4su4tMnyMp8_uiBu8BYCSOjOgck8hE0ZPzLmg@mail.gmail.com> (raw)
In-Reply-To: <x49ef3wytzz.fsf@segfault.boston.devel.redhat.com>
On Fri, Jun 14, 2019 at 10:09 AM Jeff Moyer <jmoyer@redhat.com> wrote:
>
> "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes:
>
> > On 6/14/19 10:06 PM, Dan Williams wrote:
> >> On Fri, Jun 14, 2019 at 9:26 AM Aneesh Kumar K.V
> >> <aneesh.kumar@linux.ibm.com> wrote:
> >
> >>> Why not let the arch
> >>> arch decide the SUBSECTION_SHIFT and default to one subsection per
> >>> section if arch is not enabled to work with subsection.
> >>
> >> Because that keeps the implementation from ever reaching a point where
> >> a namespace might be able to be moved from one arch to another. If we
> >> can squash these arch differences then we can have a common tool to
> >> initialize namespaces outside of the kernel. The one wrinkle is
> >> device-dax that wants to enforce the mapping size,
> >
> > The fsdax have a much bigger issue right? The file system block size
> > is the same as PAGE_SIZE and we can't make it portable across archs
> > that support different PAGE_SIZE?
>
> File system blocks are not tied to page size. They can't be *bigger*
> than the page size currently, but they can be smaller.
>
> Still, I don't see that as an arugment against trying to make the
> namespaces work across architectures. Consider a user who only has
> sector mode namespaces. We'd like that to work if at all possible.
Even with fsdax namespaces I don't see the concern. Yes, DAX might be
disabled if the filesystem on the namespace has a block size that is
smaller than the current system PAGE_SIZE, but the filesystem will
still work. I.e. it's fine to put a 512 byte block size filesystem on
a system that has a 4K PAGE_SIZE, you only lose DAX operations, not
your data access.
next prev parent reply other threads:[~2019-06-14 17:14 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-12 19:15 [PATCH -next] mm/hotplug: skip bad PFNs from pfn_to_online_page() Qian Cai
2019-06-12 19:37 ` Dan Williams
2019-06-12 19:38 ` Dan Williams
2019-06-12 21:47 ` Qian Cai
2019-06-12 21:52 ` Dan Williams
2019-06-12 23:13 ` Dan Williams
2019-06-13 0:06 ` Dan Williams
2019-06-14 8:58 ` Aneesh Kumar K.V
2019-06-14 14:59 ` Qian Cai
2019-06-14 18:03 ` Dan Williams
2019-06-14 18:57 ` Dan Williams
2019-06-14 19:40 ` Qian Cai
2019-06-14 19:48 ` Dan Williams
2019-06-14 20:43 ` Qian Cai
2019-06-16 15:42 ` Dan Williams
2019-06-17 2:25 ` Qian Cai
2019-06-14 15:35 ` Oscar Salvador
2019-06-14 16:18 ` Aneesh Kumar K.V
2019-06-14 16:22 ` Dan Williams
2019-06-14 16:26 ` Aneesh Kumar K.V
2019-06-14 16:36 ` Dan Williams
2019-06-14 16:50 ` Aneesh Kumar K.V
2019-06-14 16:55 ` Aneesh Kumar K.V
2019-06-14 17:08 ` Jeff Moyer
2019-06-14 17:14 ` Dan Williams [this message]
2019-06-14 17:40 ` Aneesh Kumar K.V
2019-06-16 3:49 ` Aneesh Kumar K.V
2019-06-17 17:21 ` Dan Williams
2019-06-13 18:42 ` Qian Cai
2019-06-14 1:17 ` Dan Williams
2019-06-14 1:29 ` Qian Cai
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