From: Dave Chinner <david@fromorbit.com>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Dan Williams <dan.j.williams@intel.com>,
Vishal Verma <vishal.l.verma@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
Matthew Wilcox <willy@infradead.org>,
Arnd Bergmann <arnd@arndb.de>,
Russell King <linux@armlinux.org.uk>,
linux-cxl@vger.kernel.org, nvdimm@lists.linux.dev,
linux-xfs@vger.kernel.org
Subject: Re: [RFC PATCH v2 7/8] Introduce dcache_is_aliasing() across all architectures
Date: Thu, 1 Feb 2024 07:42:47 +1100 [thread overview]
Message-ID: <Zbqwx12WfXvZ6kk2@dread.disaster.area> (raw)
In-Reply-To: <d30a890a-f64e-4082-8d8e-864bfb3c3800@efficios.com>
On Wed, Jan 31, 2024 at 09:58:21AM -0500, Mathieu Desnoyers wrote:
> On 2024-01-30 21:48, Dave Chinner wrote:
> > On Tue, Jan 30, 2024 at 11:52:54AM -0500, Mathieu Desnoyers wrote:
> > > Introduce a generic way to query whether the dcache is virtually aliased
> > > on all architectures. Its purpose is to ensure that subsystems which
> > > are incompatible with virtually aliased data caches (e.g. FS_DAX) can
> > > reliably query this.
> > >
> > > For dcache aliasing, there are three scenarios dependending on the
> > > architecture. Here is a breakdown based on my understanding:
> > >
> > > A) The dcache is always aliasing:
> > >
> > > * arc
> > > * csky
> > > * m68k (note: shared memory mappings are incoherent ? SHMLBA is missing there.)
> > > * sh
> > > * parisc
> >
> > /me wonders why the dentry cache aliasing has problems on these
> > systems.
> >
> > Oh, dcache != fs/dcache.c (the VFS dentry cache).
> >
> > Can you please rename this function appropriately so us dumb
> > filesystem people don't confuse cpu data cache configurations with
> > the VFS dentry cache aliasing when we read this code? Something like
> > cpu_dcache_is_aliased(), perhaps?
>
> Good point, will do. I'm planning go rename as follows for v3 to
> eliminate confusion with dentry cache (and with "page cache" in
> general):
>
> ARCH_HAS_CACHE_ALIASING -> ARCH_HAS_CPU_CACHE_ALIASING
> dcache_is_aliasing() -> cpu_dcache_is_aliasing()
>
> I noticed that you suggested "aliased" rather than "aliasing",
> but I followed what arm64 did for icache_is_aliasing(). Do you
> have a strong preference one way or another ?
Not really.
-Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2024-01-31 20:42 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-30 16:52 [RFC PATCH v2 0/8] Introduce dcache_is_aliasing() to fix DAX regression Mathieu Desnoyers
2024-01-30 16:52 ` [RFC PATCH v2 1/8] dax: Introduce dax_is_supported() Mathieu Desnoyers
2024-01-31 2:38 ` Dave Chinner
2024-01-30 16:52 ` [RFC PATCH v2 2/8] erofs: Use dax_is_supported() Mathieu Desnoyers
2024-01-30 16:52 ` [RFC PATCH v2 3/8] ext2: " Mathieu Desnoyers
2024-01-30 21:40 ` Jan Kara
2024-01-30 16:52 ` [RFC PATCH v2 4/8] ext4: " Mathieu Desnoyers
2024-01-30 16:52 ` [RFC PATCH v2 5/8] fuse: " Mathieu Desnoyers
2024-01-30 16:52 ` [RFC PATCH v2 6/8] xfs: " Mathieu Desnoyers
2024-01-30 16:52 ` [RFC PATCH v2 7/8] Introduce dcache_is_aliasing() across all architectures Mathieu Desnoyers
2024-01-31 2:48 ` Dave Chinner
2024-01-31 14:58 ` Mathieu Desnoyers
2024-01-31 20:42 ` Dave Chinner [this message]
2024-01-30 16:52 ` [RFC PATCH v2 8/8] dax: Fix incorrect list of dcache aliasing architectures Mathieu Desnoyers
2024-01-31 2:54 ` Dave Chinner
2024-01-31 3:13 ` Dan Williams
2024-01-31 15:14 ` Mathieu Desnoyers
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Zbqwx12WfXvZ6kk2@dread.disaster.area \
--to=david@fromorbit.com \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=dan.j.williams@intel.com \
--cc=dave.jiang@intel.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-cxl@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-xfs@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=mathieu.desnoyers@efficios.com \
--cc=nvdimm@lists.linux.dev \
--cc=torvalds@linux-foundation.org \
--cc=vishal.l.verma@intel.com \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).