From: David Laight <David.Laight@ACULAB.COM>
To: "'Madhavan T. Venkataraman'" <madvenka@linux.microsoft.com>,
"Andy Lutomirski" <luto@kernel.org>
Cc: "kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
"linux-api@vger.kernel.org" <linux-api@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-integrity@vger.kernel.org"
<linux-integrity@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-security-module@vger.kernel.org"
<linux-security-module@vger.kernel.org>,
"oleg@redhat.com" <oleg@redhat.com>,
"x86@kernel.org" <x86@kernel.org>
Subject: RE: [PATCH v1 0/4] [RFC] Implement Trampoline File Descriptor
Date: Wed, 29 Jul 2020 08:36:33 +0000 [thread overview]
Message-ID: <a159f2e8417746fb88f31a97c6f366ba@AcuMS.aculab.com> (raw)
In-Reply-To: <59246260-e535-a9f1-d89e-4e953288b977@linux.microsoft.com>
From: Madhavan T. Venkataraman
> Sent: 28 July 2020 19:52
...
> trampfd faults are instruction faults that go through a different code path than
> the one that calls handle_mm_fault(). Perhaps, it is the handle_mm_fault() that
> is time consuming. Could you clarify?
Given that the expectation is a few instructions in userspace
(eg to pick up the original arguments for a nested call)
the (probable) thousands of clocks taken by entering the
kernel (especially with page table separation) is a massive
delta.
If entering the kernel were cheap no one would have added
the DSO functions for getting the time of day.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
WARNING: multiple messages have this Message-ID (diff)
From: David Laight <David.Laight@ACULAB.COM>
To: "'Madhavan T. Venkataraman'" <madvenka@linux.microsoft.com>,
"Andy Lutomirski" <luto@kernel.org>
Cc: "kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
"linux-api@vger.kernel.org" <linux-api@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"oleg@redhat.com" <oleg@redhat.com>,
"linux-security-module@vger.kernel.org"
<linux-security-module@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-integrity@vger.kernel.org"
<linux-integrity@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: RE: [PATCH v1 0/4] [RFC] Implement Trampoline File Descriptor
Date: Wed, 29 Jul 2020 08:36:33 +0000 [thread overview]
Message-ID: <a159f2e8417746fb88f31a97c6f366ba@AcuMS.aculab.com> (raw)
In-Reply-To: <59246260-e535-a9f1-d89e-4e953288b977@linux.microsoft.com>
From: Madhavan T. Venkataraman
> Sent: 28 July 2020 19:52
...
> trampfd faults are instruction faults that go through a different code path than
> the one that calls handle_mm_fault(). Perhaps, it is the handle_mm_fault() that
> is time consuming. Could you clarify?
Given that the expectation is a few instructions in userspace
(eg to pick up the original arguments for a nested call)
the (probable) thousands of clocks taken by entering the
kernel (especially with page table separation) is a massive
delta.
If entering the kernel were cheap no one would have added
the DSO functions for getting the time of day.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
_______________________________________________
linux-arm-kernel mailing list
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-07-29 8:36 UTC|newest]
Thread overview: 146+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <aefc85852ea518982e74b233e11e16d2e707bc32>
2020-07-28 13:10 ` [PATCH v1 0/4] [RFC] Implement Trampoline File Descriptor madvenka
2020-07-28 13:10 ` madvenka
2020-07-28 13:10 ` [PATCH v1 1/4] [RFC] fs/trampfd: Implement the trampoline file descriptor API madvenka
2020-07-28 13:10 ` madvenka
2020-07-28 14:50 ` Oleg Nesterov
2020-07-28 14:50 ` Oleg Nesterov
2020-07-28 14:58 ` Madhavan T. Venkataraman
2020-07-28 14:58 ` Madhavan T. Venkataraman
2020-07-28 16:06 ` Oleg Nesterov
2020-07-28 16:06 ` Oleg Nesterov
2020-07-28 19:48 ` kernel test robot
2020-07-29 2:33 ` kernel test robot
2020-07-28 13:10 ` [PATCH v1 2/4] [RFC] x86/trampfd: Provide support for the trampoline file descriptor madvenka
2020-07-28 13:10 ` madvenka
2020-07-28 18:38 ` kernel test robot
2020-07-30 9:06 ` Greg KH
2020-07-30 9:06 ` Greg KH
2020-07-30 14:25 ` Madhavan T. Venkataraman
2020-07-30 14:25 ` Madhavan T. Venkataraman
2020-07-28 13:10 ` [PATCH v1 3/4] [RFC] arm64/trampfd: " madvenka
2020-07-28 13:10 ` madvenka
2020-07-28 13:10 ` [PATCH v1 4/4] [RFC] arm/trampfd: " madvenka
2020-07-28 13:10 ` madvenka
2020-07-28 15:13 ` [PATCH v1 0/4] [RFC] Implement Trampoline File Descriptor David Laight
2020-07-28 15:13 ` David Laight
2020-07-28 15:13 ` David Laight
2020-07-28 16:32 ` Madhavan T. Venkataraman
2020-07-28 16:32 ` Madhavan T. Venkataraman
2020-07-28 16:32 ` Madhavan T. Venkataraman
2020-07-28 17:16 ` Andy Lutomirski
2020-07-28 17:16 ` Andy Lutomirski
2020-07-28 17:16 ` Andy Lutomirski
2020-07-28 17:39 ` Madhavan T. Venkataraman
2020-07-29 5:16 ` Andy Lutomirski
2020-07-29 5:16 ` Andy Lutomirski
2020-07-29 5:16 ` Andy Lutomirski
2020-07-28 18:52 ` Madhavan T. Venkataraman
2020-07-28 18:52 ` Madhavan T. Venkataraman
2020-07-28 18:52 ` Madhavan T. Venkataraman
2020-07-29 8:36 ` David Laight [this message]
2020-07-29 8:36 ` David Laight
2020-07-29 8:36 ` David Laight
2020-07-29 17:55 ` Madhavan T. Venkataraman
2020-07-29 17:55 ` Madhavan T. Venkataraman
2020-07-29 17:55 ` Madhavan T. Venkataraman
2020-07-28 16:05 ` Casey Schaufler
2020-07-28 16:05 ` Casey Schaufler
2020-07-28 16:49 ` Madhavan T. Venkataraman
2020-07-28 16:49 ` Madhavan T. Venkataraman
2020-07-28 17:05 ` James Morris
2020-07-28 17:05 ` James Morris
2020-07-28 17:08 ` Madhavan T. Venkataraman
2020-07-28 17:08 ` Madhavan T. Venkataraman
2020-07-28 17:31 ` Andy Lutomirski
2020-07-28 17:31 ` Andy Lutomirski
2020-07-28 17:31 ` Andy Lutomirski
2020-07-28 19:01 ` Madhavan T. Venkataraman
2020-07-28 19:01 ` Madhavan T. Venkataraman
2020-07-29 13:29 ` Florian Weimer
2020-07-29 13:29 ` Florian Weimer
2020-07-29 13:29 ` Florian Weimer
2020-07-30 13:09 ` David Laight
2020-07-30 13:09 ` David Laight
2020-08-02 11:56 ` Pavel Machek
2020-08-02 11:56 ` Pavel Machek
2020-08-03 8:08 ` David Laight
2020-08-03 8:08 ` David Laight
2020-08-03 15:57 ` Madhavan T. Venkataraman
2020-08-03 15:57 ` Madhavan T. Venkataraman
2020-07-30 14:24 ` Madhavan T. Venkataraman
2020-07-30 20:54 ` Andy Lutomirski
2020-07-30 20:54 ` Andy Lutomirski
2020-07-30 20:54 ` Andy Lutomirski
2020-07-31 17:13 ` Madhavan T. Venkataraman
2020-07-31 17:13 ` Madhavan T. Venkataraman
2020-07-31 18:31 ` Mark Rutland
2020-07-31 18:31 ` Mark Rutland
2020-08-03 8:27 ` David Laight
2020-08-03 8:27 ` David Laight
2020-08-03 16:03 ` Madhavan T. Venkataraman
2020-08-03 16:03 ` Madhavan T. Venkataraman
2020-08-03 16:57 ` David Laight
2020-08-03 16:57 ` David Laight
2020-08-03 17:00 ` Madhavan T. Venkataraman
2020-08-03 17:00 ` Madhavan T. Venkataraman
2020-08-03 17:58 ` Madhavan T. Venkataraman
2020-08-03 17:58 ` Madhavan T. Venkataraman
2020-08-04 13:55 ` Mark Rutland
2020-08-04 13:55 ` Mark Rutland
2020-08-04 14:33 ` David Laight
2020-08-04 14:33 ` David Laight
2020-08-04 14:44 ` David Laight
2020-08-04 14:44 ` David Laight
2020-08-04 14:48 ` Madhavan T. Venkataraman
2020-08-04 14:48 ` Madhavan T. Venkataraman
2020-08-04 15:46 ` Madhavan T. Venkataraman
2020-08-04 15:46 ` Madhavan T. Venkataraman
2020-08-02 13:57 ` Florian Weimer
2020-08-02 13:57 ` Florian Weimer
2020-08-02 13:57 ` Florian Weimer
2020-07-30 14:42 ` Madhavan T. Venkataraman
2020-07-30 14:42 ` Madhavan T. Venkataraman
2020-08-02 18:54 ` Madhavan T. Venkataraman
2020-08-02 18:54 ` Madhavan T. Venkataraman
2020-08-02 20:00 ` Andy Lutomirski
2020-08-02 20:00 ` Andy Lutomirski
2020-08-02 20:00 ` Andy Lutomirski
2020-08-02 22:58 ` Madhavan T. Venkataraman
2020-08-02 22:58 ` Madhavan T. Venkataraman
2020-08-03 18:36 ` Madhavan T. Venkataraman
2020-08-03 18:36 ` Madhavan T. Venkataraman
2020-08-10 17:20 ` Madhavan T. Venkataraman
2020-08-10 17:34 ` Madhavan T. Venkataraman
2020-08-10 17:34 ` Madhavan T. Venkataraman
2020-08-11 21:12 ` Madhavan T. Venkataraman
2020-08-11 21:12 ` Madhavan T. Venkataraman
2020-08-03 8:23 ` David Laight
2020-08-03 8:23 ` David Laight
2020-08-03 15:59 ` Madhavan T. Venkataraman
2020-08-03 15:59 ` Madhavan T. Venkataraman
2020-07-31 18:09 ` Mark Rutland
2020-07-31 18:09 ` Mark Rutland
2020-07-31 20:08 ` Madhavan T. Venkataraman
2020-07-31 20:08 ` Madhavan T. Venkataraman
2020-08-03 16:57 ` Madhavan T. Venkataraman
2020-08-03 16:57 ` Madhavan T. Venkataraman
2020-08-04 14:30 ` Mark Rutland
2020-08-04 14:30 ` Mark Rutland
2020-08-06 17:26 ` Madhavan T. Venkataraman
2020-08-06 17:26 ` Madhavan T. Venkataraman
2020-08-08 22:17 ` Pavel Machek
2020-08-08 22:17 ` Pavel Machek
2020-08-11 12:41 ` Madhavan T. Venkataraman
2020-08-11 12:41 ` Madhavan T. Venkataraman
2020-08-11 13:08 ` Pavel Machek
2020-08-11 13:08 ` Pavel Machek
2020-08-11 15:54 ` Madhavan T. Venkataraman
2020-08-11 15:54 ` Madhavan T. Venkataraman
2020-08-12 10:06 ` Mark Rutland
2020-08-12 10:06 ` Mark Rutland
2020-08-12 18:47 ` Madhavan T. Venkataraman
2020-08-12 18:47 ` Madhavan T. Venkataraman
2020-08-19 18:53 ` Mickaël Salaün
2020-08-19 18:53 ` Mickaël Salaün
2020-09-01 15:42 ` Mark Rutland
2020-09-01 15:42 ` Mark Rutland
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