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From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Martin Pohlack <mpohlack@amazon.com>
Cc: Keir Fraser <keir@xen.org>,
	Ian Campbell <ian.campbell@citrix.com>,
	andrew.cooper3@citrix.com,
	Ian Jackson <ian.jackson@eu.citrix.com>, Tim Deegan <tim@xen.org>,
	mpohlack@amazon.de, ross.lagerwall@citrix.com,
	Jan Beulich <jbeulich@suse.com>,
	jinsong.liu@alibaba-inc.com, xen-devel@lists.xenproject.org,
	xen-devel@lists.xen.org, sasha.levin@citrix.com
Subject: Re: [PATCH v3 21/23] xsplice: Add support for shadow variables
Date: Tue, 15 Mar 2016 14:02:26 -0400	[thread overview]
Message-ID: <20160315180226.GA25284@char.us.oracle.com> (raw)
In-Reply-To: <56DD307F.9090609@amazon.com>

On Mon, Mar 07, 2016 at 08:40:47AM +0100, Martin Pohlack wrote:
> On 12.02.2016 19:05, Konrad Rzeszutek Wilk wrote:
> > From: Ross Lagerwall <ross.lagerwall@citrix.com>
> > 
> > Shadow variables are a piece of infrastructure to be used by xsplice
> > modules. They are used to attach a new piece of data to an existing
> > structure in memory.
> > 
> > Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
> > ---
> >  xen/common/Makefile             |   1 +
> >  xen/common/xsplice_shadow.c     | 105 ++++++++++++++++++++++++++++++++++++++++
> >  xen/include/xen/xsplice_patch.h |  39 +++++++++++++++
> >  3 files changed, 145 insertions(+)
> >  create mode 100644 xen/common/xsplice_shadow.c
> >  create mode 100644 xen/include/xen/xsplice_patch.h
> > 
> > diff --git a/xen/common/Makefile b/xen/common/Makefile
> > index a8ceaff..f4d54ad 100644
> > --- a/xen/common/Makefile
> > +++ b/xen/common/Makefile
> > @@ -75,3 +75,4 @@ subdir-$(CONFIG_HAS_DEVICE_TREE) += libfdt
> >  
> >  obj-$(CONFIG_XSPLICE) += xsplice.o
> >  obj-$(CONFIG_XSPLICE) += xsplice_elf.o
> > +obj-$(CONFIG_XSPLICE) += xsplice_shadow.o
> > diff --git a/xen/common/xsplice_shadow.c b/xen/common/xsplice_shadow.c
> > new file mode 100644
> > index 0000000..619cdee
> > --- /dev/null
> > +++ b/xen/common/xsplice_shadow.c
> > @@ -0,0 +1,105 @@
> > +#include <xen/init.h>
> > +#include <xen/kernel.h>
> > +#include <xen/lib.h>
> > +#include <xen/list.h>
> > +#include <xen/spinlock.h>
> > +#include <xen/xsplice_patch.h>
> > +
> > +#define SHADOW_SLOTS 256
> 
> Using something very round here will give you lot's of hash collisions
> at the price of a very fast hash computation as compilers, linkers, and
> memory allocators tend to align starting addresses.  I would suggest to
> use a small prime here, e.g., 257 or 251, to have a first approximation
> of a simple hash function.

Hey!

I totally missed this comment. Let me spoll this up in my TODO to
change this to 257 for v5.

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  reply	other threads:[~2016-03-15 18:02 UTC|newest]

Thread overview: 86+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-12 18:05 [PATCH v3] xSplice v1 implementation and design Konrad Rzeszutek Wilk
2016-02-12 18:05 ` [PATCH v3 01/23] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op (v10) Konrad Rzeszutek Wilk
2016-02-12 20:11   ` Andrew Cooper
2016-02-12 20:40     ` Konrad Rzeszutek Wilk
2016-02-12 20:53       ` Andrew Cooper
2016-02-15  8:16       ` Jan Beulich
2016-02-19 19:36     ` Konrad Rzeszutek Wilk
2016-02-19 19:43       ` Andrew Cooper
2016-02-12 18:05 ` [PATCH v3 02/23] libxc: Implementation of XEN_XSPLICE_op in libxc (v5) Konrad Rzeszutek Wilk
2016-02-15 12:35   ` Wei Liu
2016-02-19 20:04     ` Konrad Rzeszutek Wilk
2016-02-12 18:05 ` [PATCH v3 03/23] xen-xsplice: Tool to manipulate xsplice payloads (v4) Konrad Rzeszutek Wilk
2016-02-15 12:59   ` Wei Liu
2016-02-19 20:46     ` Konrad Rzeszutek Wilk
2016-02-12 18:05 ` [PATCH v3 04/23] elf: Add relocation types to elfstructs.h Konrad Rzeszutek Wilk
2016-02-12 20:13   ` Andrew Cooper
2016-02-15  8:34   ` Jan Beulich
2016-02-19 21:05     ` Konrad Rzeszutek Wilk
2016-02-22 10:17       ` Jan Beulich
2016-02-22 15:19       ` Ross Lagerwall
2016-02-12 18:05 ` [PATCH v3 05/23] xsplice: Add helper elf routines (v4) Konrad Rzeszutek Wilk
2016-02-12 20:24   ` Andrew Cooper
2016-02-12 20:47     ` Konrad Rzeszutek Wilk
2016-02-12 20:52       ` Andrew Cooper
2016-02-12 18:05 ` [PATCH v3 06/23] xsplice: Implement payload loading (v4) Konrad Rzeszutek Wilk
2016-02-12 20:48   ` Andrew Cooper
2016-02-19 22:03     ` Konrad Rzeszutek Wilk
2016-02-12 18:05 ` [PATCH v3 07/23] xsplice: Implement support for applying/reverting/replacing patches. (v5) Konrad Rzeszutek Wilk
2016-02-16 19:11   ` Andrew Cooper
2016-02-17  8:58     ` Ross Lagerwall
2016-02-17 10:50     ` Jan Beulich
2016-02-19  9:30     ` Ross Lagerwall
2016-02-23 20:41     ` Konrad Rzeszutek Wilk
2016-02-23 20:53       ` Konrad Rzeszutek Wilk
2016-02-23 20:57       ` Konrad Rzeszutek Wilk
2016-02-23 21:10       ` Andrew Cooper
2016-02-24  9:31         ` Jan Beulich
2016-02-22 15:00   ` Ross Lagerwall
2016-02-22 17:06     ` Ross Lagerwall
2016-02-23 20:47       ` Konrad Rzeszutek Wilk
2016-02-23 20:43     ` Konrad Rzeszutek Wilk
2016-02-12 18:05 ` [PATCH v3 08/23] x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version'. (v2) Konrad Rzeszutek Wilk
2016-02-16 11:31   ` Ross Lagerwall
2016-02-12 18:05 ` [PATCH v3 09/23] xsplice: Add support for bug frames. (v4) Konrad Rzeszutek Wilk
2016-02-16 19:35   ` Andrew Cooper
2016-02-24 16:22     ` Konrad Rzeszutek Wilk
2016-02-24 16:30       ` Andrew Cooper
2016-02-24 16:26     ` Konrad Rzeszutek Wilk
2016-02-12 18:05 ` [PATCH v3 10/23] xsplice: Add support for exception tables. (v2) Konrad Rzeszutek Wilk
2016-02-12 18:05 ` [PATCH v3 11/23] xsplice: Add support for alternatives Konrad Rzeszutek Wilk
2016-02-16 19:41   ` Andrew Cooper
2016-02-12 18:05 ` [PATCH v3 12/23] xsm/xen_version: Add XSM for the xen_version hypercall (v8) Konrad Rzeszutek Wilk
2016-02-12 21:52   ` Daniel De Graaf
2016-02-12 18:05 ` [PATCH v3 13/23] XENVER_build_id: Provide ld-embedded build-ids (v10) Konrad Rzeszutek Wilk
2016-02-12 21:52   ` Daniel De Graaf
2016-02-16 20:09   ` Andrew Cooper
2016-02-16 20:22     ` Konrad Rzeszutek Wilk
2016-02-16 20:26       ` Andrew Cooper
2016-02-16 20:40         ` Konrad Rzeszutek Wilk
2016-02-24 18:52     ` Konrad Rzeszutek Wilk
2016-02-24 19:13       ` Andrew Cooper
2016-02-24 20:54         ` Konrad Rzeszutek Wilk
2016-02-12 18:05 ` [PATCH v3 14/23] libxl: info: Display build_id of the hypervisor Konrad Rzeszutek Wilk
2016-02-15 12:45   ` Wei Liu
2016-02-12 18:05 ` [PATCH v3 15/23] xsplice: Print build_id in keyhandler Konrad Rzeszutek Wilk
2016-02-16 20:13   ` Andrew Cooper
2016-02-12 18:05 ` [PATCH v3 16/23] xsplice: basic build-id dependency checking Konrad Rzeszutek Wilk
2016-02-12 18:05 ` [PATCH v3 17/23] xsplice: Print dependency and payloads build_id in the keyhandler Konrad Rzeszutek Wilk
2016-02-16 20:20   ` Andrew Cooper
2016-02-17 11:10     ` Jan Beulich
2016-02-24 21:54       ` Konrad Rzeszutek Wilk
2016-02-25  8:47         ` Jan Beulich
2016-02-12 18:05 ` [PATCH v3 18/23] xsplice: Prevent duplicate payloads to be loaded Konrad Rzeszutek Wilk
2016-02-12 18:05 ` [PATCH v3 19/23] xsplice, symbols: Implement symbol name resolution on address. (v2) Konrad Rzeszutek Wilk
2016-02-22 14:57   ` Ross Lagerwall
2016-02-12 18:05 ` [PATCH v3 20/23] x86, xsplice: Print payload's symbol name and module in backtraces Konrad Rzeszutek Wilk
2016-02-12 18:05 ` [PATCH v3 21/23] xsplice: Add support for shadow variables Konrad Rzeszutek Wilk
2016-03-07  7:40   ` Martin Pohlack
2016-03-15 18:02     ` Konrad Rzeszutek Wilk [this message]
2016-03-07 18:52   ` Martin Pohlack
2016-02-12 18:06 ` [PATCH v3 22/23] xsplice: Add hooks functions and other macros Konrad Rzeszutek Wilk
2016-02-12 18:06 ` [PATCH v3 23/23] xsplice, hello_world: Use the XSPLICE_[UN|]LOAD_HOOK hooks for two functions Konrad Rzeszutek Wilk
2016-02-12 21:57 ` [PATCH v3] xSplice v1 implementation and design Konrad Rzeszutek Wilk
2016-02-12 21:57   ` [PATCH v3 MISSING/23] xsplice: Design document (v7) Konrad Rzeszutek Wilk
2016-02-18 16:20     ` Jan Beulich
2016-02-19 18:36       ` Konrad Rzeszutek Wilk

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