From: Dave Hansen <dave.hansen@intel.com>
To: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>,
linux-next@vger.kernel.org, akpm@linux-foundation.org,
jack@suse.cz, kirill@shutemov.name, "Edgecombe,
Rick P" <rick.p.edgecombe@intel.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
borntraeger@de.ibm.com, david@redhat.com, aarcange@redhat.com,
linux-mm@kvack.org, frankja@linux.ibm.com, sfr@canb.auug.org.au,
jhubbard@nvidia.com, linux-kernel@vger.kernel.org,
linux-s390@vger.kernel.org, Will Deacon <will@kernel.org>,
"Williams, Dan J" <dan.j.williams@intel.com>
Subject: Re: [PATCH v4 2/2] mm/gup/writeback: add callbacks for inaccessible pages
Date: Thu, 16 Apr 2020 07:20:48 -0700 [thread overview]
Message-ID: <de56aa8e-9035-4b68-33cb-15682d073e26@intel.com> (raw)
In-Reply-To: <20200416141547.29be5ea0@p-imbrenda>
On 4/16/20 5:15 AM, Claudio Imbrenda wrote:
>> I assumed that this was all anonymous-only so it's always dirty before
>> writeback starts.
> it could also be mmapped
Let's say you have a mmap()'d ramfs file. Another process calls which
doesn't have it mapped calls sys_write() and writes to the file.
This means that host host has to write to the physical page and must do
arch_make_page_accessible() in the sys_write() path somewhere.
There is a get_user_pages() in that path, but it's on the _source_
buffer, not the ramfs page because the ramfs page is not mapped.
There's also no __test_set_page_writeback() because you can't write back
ramfs.
Where is the arch_make_page_accessible() in this case on the ramfs page?
next prev parent reply other threads:[~2020-04-16 14:20 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-06 13:25 [PATCH v4 0/2] add callbacks for inaccessible pages Claudio Imbrenda
2020-03-06 13:25 ` [PATCH v4 1/2] mm/gup: fixup for 9947ea2c1e608e32 "mm/gup: track FOLL_PIN pages" Claudio Imbrenda
2020-03-06 13:25 ` [PATCH v4 2/2] mm/gup/writeback: add callbacks for inaccessible pages Claudio Imbrenda
2020-04-13 20:22 ` Dave Hansen
2020-04-14 16:03 ` Claudio Imbrenda
2020-04-14 18:50 ` Dave Hansen
2020-04-15 9:26 ` Claudio Imbrenda
2020-04-15 11:39 ` Janosch Frank
2020-04-15 21:52 ` Dave Hansen
2020-04-15 22:17 ` Peter Zijlstra
2020-04-15 23:34 ` Dave Hansen
2020-04-16 12:15 ` Claudio Imbrenda
2020-04-16 14:20 ` Dave Hansen [this message]
2020-04-16 14:59 ` Claudio Imbrenda
2020-04-16 15:36 ` Dave Hansen
2020-04-16 16:34 ` Claudio Imbrenda
2020-04-16 19:02 ` Dave Hansen
2020-04-21 21:31 ` Dave Hansen
2020-04-28 19:43 ` Dave Hansen
2020-04-28 20:02 ` Christian Borntraeger
2020-04-28 23:39 ` Claudio Imbrenda
2020-04-29 0:42 ` Dave Hansen
2020-04-16 11:51 ` Claudio Imbrenda
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