From: Matthew Wilcox <willy@infradead.org>
To: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Nathaniel McCallum <nathaniel@profian.com>,
Reinette Chatre <reinette.chatre@intel.com>,
linux-sgx@vger.kernel.org, linux-mips@vger.kernel.org,
linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org,
dri-devel@lists.freedesktop.org, codalist@coda.cs.cmu.edu,
linux-unionfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH RFC] mm: Add f_ops->populate()
Date: Sun, 6 Mar 2022 03:52:12 +0000 [thread overview]
Message-ID: <YiQv7JEBPzgYUTTa@casper.infradead.org> (raw)
In-Reply-To: <YiQop71ABWm7hbMy@iki.fi>
On Sun, Mar 06, 2022 at 05:21:11AM +0200, Jarkko Sakkinen wrote:
> On Sun, Mar 06, 2022 at 02:57:55AM +0000, Matthew Wilcox wrote:
> > On Sun, Mar 06, 2022 at 04:15:33AM +0200, Jarkko Sakkinen wrote:
> > > Sometimes you might want to use MAP_POPULATE to ask a device driver to
> > > initialize the device memory in some specific manner. SGX driver can use
> > > this to request more memory by issuing ENCLS[EAUG] x86 opcode for each
> > > page in the address range.
> > >
> > > Add f_ops->populate() with the same parameters as f_ops->mmap() and make
> > > it conditionally called inside call_mmap(). Update call sites
> > > accodingly.
> >
> > Your device driver has a ->mmap operation. Why does it need another
> > one? More explanation required here.
>
> f_ops->mmap() would require an additional parameter, which results
> heavy refactoring.
>
> struct file_operations has 1125 references in the kernel tree, so I
> decided to check this way around first.
Are you saying that your device driver behaves differently if
MAP_POPULATE is set versus if it isn't? That seems hideously broken.
next prev parent reply other threads:[~2022-03-06 3:52 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-06 2:15 [PATCH RFC] mm: Add f_ops->populate() Jarkko Sakkinen
2022-03-06 2:57 ` Matthew Wilcox
2022-03-06 3:21 ` Jarkko Sakkinen
2022-03-06 3:52 ` Matthew Wilcox [this message]
2022-03-06 4:11 ` Jarkko Sakkinen
2022-03-06 4:19 ` Matthew Wilcox
2022-03-06 4:25 ` Jarkko Sakkinen
2022-03-06 4:36 ` Matthew Wilcox
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