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)
next prev parent reply other threads:[~2020-07-29 8:36 UTC|newest] Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <aefc85852ea518982e74b233e11e16d2e707bc32> 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 14:50 ` Oleg Nesterov 2020-07-28 14:58 ` Madhavan T. Venkataraman 2020-07-28 16:06 ` Oleg Nesterov 2020-07-28 13:10 ` [PATCH v1 2/4] [RFC] x86/trampfd: Provide support for the trampoline file descriptor madvenka 2020-07-30 9:06 ` Greg KH 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 ` [PATCH v1 4/4] [RFC] arm/trampfd: " madvenka 2020-07-28 15:13 ` [PATCH v1 0/4] [RFC] Implement Trampoline File Descriptor David Laight 2020-07-28 16:32 ` Madhavan T. Venkataraman 2020-07-28 17:16 ` Andy Lutomirski 2020-07-28 18:52 ` Madhavan T. Venkataraman 2020-07-29 8:36 ` David Laight [this message] 2020-07-29 17:55 ` Madhavan T. Venkataraman [not found] ` <81d744c0-923e-35ad-6063-8b186f6a153c@linux.microsoft.com> 2020-07-29 5:16 ` Andy Lutomirski 2020-07-28 16:05 ` Casey Schaufler 2020-07-28 16:49 ` Madhavan T. Venkataraman 2020-07-28 17:05 ` James Morris 2020-07-28 17:08 ` Madhavan T. Venkataraman 2020-07-28 17:31 ` Andy Lutomirski 2020-07-28 19:01 ` Madhavan T. Venkataraman 2020-07-29 13:29 ` Florian Weimer 2020-07-30 13:09 ` David Laight 2020-08-02 11:56 ` Pavel Machek 2020-08-03 8:08 ` David Laight 2020-08-03 15:57 ` Madhavan T. Venkataraman 2020-07-30 14:42 ` Madhavan T. Venkataraman [not found] ` <6540b4b7-3f70-adbf-c922-43886599713a@linux.microsoft.com> 2020-07-30 20:54 ` Andy Lutomirski 2020-07-31 17:13 ` Madhavan T. Venkataraman 2020-07-31 18:31 ` Mark Rutland 2020-08-03 8:27 ` David Laight 2020-08-03 16:03 ` Madhavan T. Venkataraman 2020-08-03 16:57 ` David Laight 2020-08-03 17:00 ` Madhavan T. Venkataraman 2020-08-03 17:58 ` Madhavan T. Venkataraman 2020-08-04 13:55 ` Mark Rutland 2020-08-04 14:33 ` David Laight 2020-08-04 14:44 ` David Laight 2020-08-04 14:48 ` Madhavan T. Venkataraman 2020-08-04 15:46 ` Madhavan T. Venkataraman 2020-08-02 13:57 ` Florian Weimer 2020-08-02 18:54 ` Madhavan T. Venkataraman 2020-08-02 20:00 ` Andy Lutomirski 2020-08-02 22:58 ` Madhavan T. Venkataraman 2020-08-03 18:36 ` Madhavan T. Venkataraman 2020-08-10 17:34 ` Madhavan T. Venkataraman 2020-08-11 21:12 ` Madhavan T. Venkataraman 2020-08-03 8:23 ` David Laight 2020-08-03 15:59 ` Madhavan T. Venkataraman 2020-07-31 18:09 ` Mark Rutland 2020-07-31 20:08 ` Madhavan T. Venkataraman 2020-08-03 16:57 ` Madhavan T. Venkataraman 2020-08-04 14:30 ` Mark Rutland 2020-08-06 17:26 ` Madhavan T. Venkataraman 2020-08-08 22:17 ` Pavel Machek 2020-08-11 12:41 ` Madhavan T. Venkataraman 2020-08-11 13:08 ` Pavel Machek 2020-08-11 15:54 ` Madhavan T. Venkataraman 2020-08-12 10:06 ` Mark Rutland 2020-08-12 18:47 ` Madhavan T. Venkataraman 2020-08-19 18:53 ` Mickaël Salaün 2020-09-01 15:42 ` Mark Rutland
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=a159f2e8417746fb88f31a97c6f366ba@AcuMS.aculab.com \ --to=david.laight@aculab.com \ --cc=kernel-hardening@lists.openwall.com \ --cc=linux-api@vger.kernel.org \ --cc=linux-arm-kernel@lists.infradead.org \ --cc=linux-fsdevel@vger.kernel.org \ --cc=linux-integrity@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-security-module@vger.kernel.org \ --cc=luto@kernel.org \ --cc=madvenka@linux.microsoft.com \ --cc=oleg@redhat.com \ --cc=x86@kernel.org \ --subject='RE: [PATCH v1 0/4] [RFC] Implement Trampoline File Descriptor' \ /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
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 NNTP newsgroup(s).