From: Oliver <oohall@gmail.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: "linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>
Subject: Re: [PATCH 2/4] ndctl/namespace: Check for seed namespaces earlier
Date: Wed, 28 Nov 2018 00:27:11 +1100 [thread overview]
Message-ID: <CAOSf1CH1yGws3c0aOJZCLvsUxf5mvqtkQpe3CY7KS7UdKjMjuQ@mail.gmail.com> (raw)
In-Reply-To: <CAPcyv4idzcVa8XnA1G8DjEux=RRvCi_wF8hBk=4jmg1JFuRdDA@mail.gmail.com>
On Mon, Nov 26, 2018 at 7:12 AM Dan Williams <dan.j.williams@intel.com> wrote:
>
> On Mon, Nov 19, 2018 at 12:11 AM Oliver O'Halloran <oohall@gmail.com> wrote:
> >
> > When creating an fsdax or devdax namespace we need to verify that the
> > seed namespaces exist. This patch reworks the validation so that it's
> > done earlier to simplify the subsequent patches in the series.
> >
> > No functional changes.
>
> It does appear to have a functional change. do_setup_pfn() supports
> the case of statically allocated namespaces in NDCTL_NS_MODE_MEMORY
> mode.
Hmm, ok. Up until now I had assumed that as far as ndctl was concerned
NS_MODE_MEMORY was synonymous with a pfn namespace.
> This is what one gets by default with "legacy" pmem defined as
> E820-type-12 memory. In that case the kernel assumes that the
> resulting memmap is always small enough to be allocated from DRAM and
> there is no need to use a dynamic pfn device. So, if I'm not
> mistaken, the deletion of do_setup_pfn() loses that special case
> handling.
>From what I see, the main difference is that ndctl would fail
validation when fsdax mode is specified and there's no pfn namespace
support in the kernel. I agree that's not great, but I'm not sure what
we should be doing here. The current behaviour will silently ignore -a
if "-m fsdax -M mem" is specified in the reconfigure case, which
doesn't seem great either.
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next prev parent reply other threads:[~2018-11-27 13:27 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-19 8:00 [PATCH 1/4] libndctl: Use the supported_alignment attribute Oliver O'Halloran
2018-11-19 8:00 ` [PATCH 2/4] ndctl/namespace: Check for seed namespaces earlier Oliver O'Halloran
2018-11-25 20:12 ` Dan Williams
2018-11-27 13:27 ` Oliver [this message]
2019-01-08 2:59 ` Dan Williams
2019-01-08 11:00 ` Oliver
2018-11-19 8:00 ` [PATCH 3/4] ndctl/namespace: Use seed alignment as the default Oliver O'Halloran
2018-11-25 20:14 ` Dan Williams
2018-11-19 8:00 ` [PATCH 4/4] ndctl/namespace: Validate alignment from the {pfn|dax} seed Oliver O'Halloran
2018-11-25 20:18 ` Dan Williams
2018-11-25 20:06 ` [PATCH 1/4] libndctl: Use the supported_alignment attribute Dan Williams
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