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 08:36:50 -0700 [thread overview]
Message-ID: <a6b8728d-7382-9316-412d-dd48b5e7c41a@intel.com> (raw)
In-Reply-To: <20200416165900.68bd4dba@p-imbrenda>
On 4/16/20 7:59 AM, Claudio Imbrenda wrote:
> On Thu, 16 Apr 2020 07:20:48 -0700
> Dave Hansen <dave.hansen@intel.com> wrote:
>> 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.
...
>> Where is the arch_make_page_accessible() in this case on the ramfs
>> page?
>
> it's in the fault handler for the exception the CPU will get when
> attempting to write the data to the protected page
Ahh, so this is *just* intended to precede I/O done on the page, when a
non-host entity is touching the memory?
That seems inconsistent with the process_vm_readv/writev() paths which
set FOLL_PIN on their pin_remote_user_pages() requests, but don't do I/O
to the memory.
next prev parent reply other threads:[~2020-04-16 15:36 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
2020-04-16 14:59 ` Claudio Imbrenda
2020-04-16 15:36 ` Dave Hansen [this message]
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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