Граф коммитов

110336 Коммитов

Автор SHA1 Сообщение Дата
Malcolm Turnbull 4856c84c13 ipvs: load balance IPv4 connections from a local process
This allows IPVS to load balance connections made by a local process.
For example a proxy server running locally.

External client --> pound:443 -> Local:443 --> IPVS:80 --> RealServer

Signed-off-by: Siim Põder <siim@p6drad-teel.net>
Signed-off-by: Malcolm Turnbull <malcolm@loadbalancer.org>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:13 +10:00
Julius Volz f94fd04140 IPVS: Allow adding IPv6 services from userspace
Allow adding IPv6 services through the genetlink interface and add checks
to see if the chosen scheduler is supported with IPv6 and whether the
supplied prefix length is sane. Make sure the service count exported via
the sockopt interface only counts IPv4 services.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:13 +10:00
Julius Volz 473b23d37b IPVS: Activate IPv6 Netfilter hooks
Register the previously defined or adapted netfilter hook functions for
IPv6 as PF_INET6 hooks.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:13 +10:00
Julius Volz cfc78c5a09 IPVS: Adjust various debug outputs to use new macros
Adjust various debug outputs to use the new *_BUF macro variants for
correct output of v4/v6 addresses.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:12 +10:00
Vince Busam 09571c7ae3 IPVS: Add function to determine if IPv6 address is local
Add __ip_vs_addr_is_local_v6() to find out if an IPv6 address belongs to a
local interface. Use this function to decide whether to set the
IP_VS_CONN_F_LOCALNODE flag for IPv6 destinations.

Signed-off-by: Vince Busam <vbusam@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:12 +10:00
Julius Volz a0eb662f9e IPVS: Turn off FTP application helper for IPv6
Immediately return from FTP application helper and do nothing when dealing
with IPv6 packets. IPv6 is not supported by this helper yet.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:11 +10:00
Julius Volz c6883f5873 IVPS: Disable sync daemon for IPv6 connections
Disable the sync daemon for IPv6 connections, works only with IPv4 for now.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:11 +10:00
Vince Busam 667a5f1816 IPVS: Convert procfs files for IPv6 entry output
Correctly output IPv6 connection/service/dest entries in procfs files.

Signed-off-by: Vince Busam <vbusam@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:10 +10:00
Julius Volz 7937df1564 IPVS: Convert real server lookup functions
Convert functions for looking up destinations (real servers) to support
IPv6 services/dests.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:10 +10:00
Julius Volz 2a3b791e6e IPVS: Add/adjust Netfilter hook functions and helpers for v6
Add Netfilter hook functions or modify existing ones, if possible, to
process IPv6 packets. Some support functions are also added/modified for
this. ip_vs_nat_icmp_v6() was already added in the patch that added the v6
xmit functions, as it is called from one of them.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:09 +10:00
Julius Volz cd17f9ed09 IPVS: Extend scheduling functions for IPv6 support
Convert ip_vs_schedule() and ip_vs_sched_persist() to support scheduling of
IPv6 connections.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:09 +10:00
Julius Volz b3cdd2a738 IPVS: Add and bind IPv6 xmit functions
Add xmit functions for IPv6. Also add the already needed __ip_vs_get_out_rt_v6()
to ip_vs_core.c. Bind the new xmit functions to v6 connections.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:08 +10:00
Julius Volz 38cdcc9a03 IPVS: Add IPv6 support to xmit() support functions
Add IPv6 support to IP_VS_XMIT() and to the xmit routing cache, introducing
a new function __ip_vs_get_out_rt_v6().

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:08 +10:00
Julius Volz 28364a59f3 IPVS: Extend functions for getting/creating connections
Extend functions for getting/creating connections and connection
templates for IPv6 support and fix the callers.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:08 +10:00
Julius Volz 0bbdd42b7e IPVS: Extend protocol DNAT/SNAT and state handlers
Extend protocol DNAT/SNAT and state handlers to work with IPv6. Also
change/introduce new checksumming helper functions for this.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:07 +10:00
Julius Volz 3b047d9d04 IPVS: Add protocol debug functions for IPv6
Add protocol (TCP, UDP, AH, ESP) debug functions for IPv6 packet debug
output.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:06 +10:00
Julius Volz 51ef348b14 IPVS: Add 'af' args to protocol handler functions
Add 'af' arguments to conn_schedule(), conn_in_get(), conn_out_get() and
csum_check() function pointers in struct ip_vs_protocol. Extend the
respective functions for TCP, UDP, AH and ESP and adjust the callers.

The changes in the callers need to be somewhat extensive, since they now
need to pass a filled out struct ip_vs_iphdr * to the modified functions
instead of a struct iphdr *.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:06 +10:00
Julius Volz b14198f6c1 IPVS: Add IPv6 support flag to schedulers
Add 'supports_ipv6' flag to struct ip_vs_scheduler to indicate whether a
scheduler supports IPv6. Set the flag to 1 in schedulers that work with
IPv6, 0 otherwise. This flag is checked in a later patch while trying to
add a service with a specific scheduler. Adjust debug in v6-supporting
schedulers to work with both address families.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:06 +10:00
Julius Volz 3c2e0505d2 IPVS: Add v6 support to ip_vs_service_get()
Add support for selecting services based on their address family to
ip_vs_service_get() and adjust the callers.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:05 +10:00
Julius Volz b18610de9e IPVS: Convert __ip_vs_svc_get() and __ip_vs_fwm_get()
Add support for getting services based on their address family to
__ip_vs_service_get(), __ip_vs_fwm_get() and the helper hash function
ip_vs_svc_hashkey(). Adjust the callers.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:05 +10:00
Julius Volz c860c6b147 IPVS: Add internal versions of sockopt interface structs
Add extended internal versions of struct ip_vs_service_user and struct
ip_vs_dest_user (the originals can't be modified as they are part
of the old sockopt interface). Adjust ip_vs_ctl.c to work with the new
data structures and add some minor AF-awareness.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:04 +10:00
Julius Volz c842a3ada9 IPVS: Add debug macros for v4 and v6 address output
Add some debugging macros that allow conditional output of either v4 or v6
addresses, depending on an 'af' parameter. This is done by creating a
temporary string buffer in an outer debug macro and writing addresses'
string representations into it from another macro which can only be used
when inside the outer one.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:04 +10:00
Julius Volz 64aae3cb9f IPVS: Add general v4/v6 helper functions / data structures
Add a struct ip_vs_iphdr for easier handling of common v4 and v6 header
fields in the same code path. ip_vs_fill_iphdr() helps to fill this struct
from an IPv4 or IPv6 header. Add further helper functions for copying and
comparing addresses.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:03 +10:00
Julius Volz e7ade46a53 IPVS: Change IPVS data structures to support IPv6 addresses
Introduce new 'af' fields into IPVS data structures for specifying an
entry's address family. Convert IP addresses to be of type union
nf_inet_addr.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:03 +10:00
Julius Volz fab0de02fb IPVS: Add CONFIG_IP_VS_IPV6 option for IPv6 support
Add boolean config option CONFIG_IP_VS_IPV6 for enabling experimental IPv6
support in IPVS. Only visible if IPv6 support is set to 'y' or both IPv6
and IPVS are modules.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:02 +10:00
Jeremy Kerr b65fe0356b powerpc/spufs: Fix race for a free SPU
We currently have a race for a free SPE. With one thread doing a
spu_yield(), and another doing a spu_activate():

thread 1				thread 2
spu_yield(oldctx)			spu_activate(ctx)
  __spu_deactivate(oldctx)
  spu_unschedule(oldctx, spu)
  spu->alloc_state = SPU_FREE
					spu = spu_get_idle(ctx)
					    - searches for a SPE in
					      state SPU_FREE, gets
					      the context just
					      freed by thread 1
					spu_schedule(ctx, spu)
					  spu->alloc_state = SPU_USED
spu_schedule(newctx, spu)
  - assumes spu is still free
  - tries to schedule context on
    already-used spu

This change introduces a 'free_spu' flag to spu_unschedule, to indicate
whether or not the function should free the spu after descheduling the
context. We only set this flag if we're not going to re-schedule
another context on this SPU.

Add a comment to document this behaviour.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
2008-09-05 10:52:03 +10:00
Jeremy Kerr 9f43e3914d powerpc/spufs: Fix multiple get_spu_context()
Commit 8d5636fbca introduced a reference
count on SPU contexts during find_victim, but this may cause a leak in
the reference count if we later find a better contender for a context to
unschedule.

Change the reference to after we've found our victim context, so we
don't do the extra get_spu_context().

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
2008-09-05 10:51:00 +10:00
Li Zefan 8561098ff1 V4L/DVB (8881): gspca: After 'while (retry--) {...}', retry will be -1 but not 0.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2008-09-04 18:27:51 -03:00
Hans de Goede 748c7f80ac V4L/DVB (8880): PATCH: Fix parents on some webcam drivers
While doing some testing using Luca Risolia's sonix driver I noticed that
the video device did not get ACL's set to allow access by locally logged in
users, nor does it show up as a video device in lshal, causing cheese to not
see it.

This turns out to be caused by all of Luca Risolia's drivers not setting
the parent member of the video_device struct. This patch fixes this.

Cc: Luca Risolia <luca.risolia@studio.unibo.it>
Signed-off-by: Hans de Goede <j.w.r.degoede@hhs.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2008-09-04 18:27:35 -03:00
Thierry MERLE c4e3fd940c V4L/DVB (8877): b2c2 and bt8xx: udelay to mdelay
b2c2-flexcop, dvb/bt8xx and video/bt8xx fails to build on ARM with:

__bad_udelay is specifically designed on ARM to fail when udelay is
called in a bad way.  arch/arm/include/asm/delay.h has this to say
about __bad_udelay:

/*
 * This function intentionally does not exist; if you see references to
 * it, it means that you're calling udelay() with an out of range value.
 *
 * With currently imposed limits, this means that we support a max delay
 * of 2000us. Further limits: HZ<=1000 and bogomips<=3355
 */
extern void __bad_udelay(void);

Solution is to replace udelay by a mdelay and udelay with value less than 2000

Signed-off-by: Thierry MERLE <thierry.merle@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2008-09-04 18:27:03 -03:00
Thierry MERLE db210426d4 V4L/DVB (8876): budget: udelay changed to mdelay
budget.ko fails to build on ARM with:

ERROR: "__bad_udelay" [drivers/media/dvb/ttpci/budget.ko] undefined!
make[1]: *** [__modpost] Error 1

__bad_udelay is specifically designed on ARM to fail when udelay is
called in a bad way.  arch/arm/include/asm/delay.h has this to say
about __bad_udelay:

/*
 * This function intentionally does not exist; if you see references to
 * it, it means that you're calling udelay() with an out of range value.
 *
 * With currently imposed limits, this means that we support a max delay
 * of 2000us. Further limits: HZ<=1000 and bogomips<=3355
 */
extern void __bad_udelay(void);

Solution is to replace udelay by a mdelay and udelay with value less than 2000

Acked-by: Oliver Endriss <o.endriss@gmx.de>
Signed-off-by: Thierry MERLE <thierry.merle@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2008-09-04 18:26:48 -03:00
Russell King 65846909d6 [ARM] omap: fix virtual vs physical address space confusions
mcbsp is confused as to what takes a physical or virtual address.
Fix the two instances where it gets it wrong.

Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-04 22:21:19 +01:00
Mauro Carvalho Chehab db0a2901a3 Merge branch 'fixes_stg' of ../git_old into fixes 2008-09-04 16:24:02 -03:00
Hans de Goede 4cce1655b2 V4L/DVB (8874): gspca: Adjust hstart for sn9c103/ov7630 and update usb-id's.
- Adjust hstart in ov7630 on sn9c103 initdata to shift bayer pattern, this is
 the same change as done for the other initdata tables in a previous patch.
- Assign usb-id's for the ov7630 + sn9c103 to gspca if gspca and sn9c102
  drivers are both enabled.

Signed-off-by: Hans de Goede <j.w.r.degoede@hhs.nl>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2008-09-04 16:22:57 -03:00
Hans de Goede 0fc23d2069 V4L/DVB (8873): gspca: Bad image offset with rev012a of spca561 and adjust exposure.
-Make raw bayer header size change from 20 to 16 affect rev072a only, my 2
 rev012a cams both have a header size of 20
-While testing this I also tested the new exposure setting (good work on
 finding the register JF), and after quite a bit of testing have found out the
 exact meaning of the register, this patch modifies setexposure to control
 the exposure over a much wider range.

Signed-off-by: Hans de Goede <j.w.r.degoede@hhs.nl>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2008-09-04 16:22:57 -03:00
Jean-Francois Moine b77c0046a6 V4L/DVB (8872): gspca: Bad image format and offset with rev072a of spca561.
- have 2 pixfmt tables
- offset of Bayer frames at 16 instead of 20.

Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2008-09-04 16:22:56 -03:00
Hans de Goede bf2a2202f7 V4L/DVB (8870): gspca: Fix dark room problem with sonixb.
When using the sonixb driver in a dark room and given that the autoexposure
algorithm starts with a setting most suitable for daylight, the picture
produced by the cam may actually be 100% black leading to a avg_lum value of 0,
so an avg_lum value of 0 does not always signal an exposure settings change
(which it normally does). This patch adds a check for the really black image
case and stops dropping all frames as invalid in this case.

Signed-off-by: Hans de Goede <j.w.r.degoede@hhs.nl>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2008-09-04 16:22:56 -03:00
Hans de Goede a94a508691 V4L/DVB (8869): gspca: Move the Sonix webcams with TAS5110C1B from sn9c102 to gspca.
This patch makes gspca claim the USB-ID for sn9c101/2 cams with a TAS5110C1B
sensor even if both gspca and sn9c102 are enabled, as these cams are much
better supported under gspca (and extensively tested with gspca).
It also removes an usb-id from sn9c102 for one more unsupported bridge
sensor combo.

Signed-off-by: Hans de Goede <j.w.r.degoede@hhs.nl>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2008-09-04 16:22:55 -03:00
Hans de Goede 9362773624 V4L/DVB (8868): gspca: Support for vga modes with sif sensors in sonixb.
- Add documentation for some known registers
- Add support for vga modes (320x240, 160x120) for sif sensors
- Remove F_RAW sensor flag raw mode should work on any sensor as its a bridge
   only thing and keeping the flag was becoming awkward.
- Fixup ov6650 and pas106 auto exposure window settings

Signed-off-by: Hans de Goede <j.w.r.degoede@hhs.nl>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2008-09-04 16:20:12 -03:00
Al Viro b380b0d4f7 forgotten refcount on sysctl root table
We should've set refcount on the root sysctl table; otherwise we'll blow
up the first time we get down to zero dynamically registered sysctl
tables.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-04 11:06:21 -07:00
Andi Kleen 5ed459102d Merge branch 'wmi-fix' into release-2.6.27 2008-09-04 14:41:02 +02:00
Russ Dill 7d964c352b acer-wmi: remove debugfs entries upon unloading
The exit function neglects to remove debugfs entries, leading to a BUG
on reload.

[akpm@linux-foundation.org: cleanups]
Signed-off-by: Russ Dill <Russ.Dill@gmail.com>
Acked-by: Carlos Corbacho <carlos@strangeworlds.co.uk>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2008-09-04 14:40:48 +02:00
Andi Kleen 4fd23436f1 Merge branches 'smbus' and 'fujitsu-fix' into release-2.6.27 2008-09-04 14:33:03 +02:00
Zhao Yakui 266feefeb9 ACPI: Avoid bogus timeout about SMbus check
In the function of wait_transaction_complete when the timeout happens,
OS will try to check the status of SMbus again. If the status is what OS
expected, it will be regarded as the bogus timeout. Otherwise it will be
treated as ETIME.

http://bugzilla.kernel.org/show_bug.cgi?id=10483

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
tested-by    : Oldřich Jedlička < <oldium.pro@seznam.cz>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2008-09-04 14:32:28 +02:00
Jonathan Woithe d8196a93b1 fujitsu-laptop: fix regression for P8010 in 2.6.27-rc
The following patch (based on a patch from Stephen Gildea) fixes a
regression with the LCD brightness keys on Fujitsu P8010 laptops which was
observed with the 2.6.27-rc series (basically they stopped working due to
changes within the fujitsu-laptop and video modules).  Please apply to
2.6.27-rc and acpi git.

A more complete solution for this laptop will be included in an upcoming
patch, hopefully for 2.6.28.  In the meantime this restores most
functionality for P8010 users.

Signed-off-by: Stephen Gildea <stepheng+fujitsu-laptop@gildea.com>
Signed-off-by: Jonathan Woithe <jwoithe@physics.adelaide.edu.au>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2008-09-04 14:31:08 +02:00
Andi Kleen 54cd3148a1 ACPI: Make Len Brown the ACPI maintainer again
Len is back!

Signed-off-by: Andi Kleen <ak@linux.intel.com>
2008-09-04 13:30:07 +02:00
Huang Weiyi 8b540fdcb7 [ARM] remove unused #include <version.h>
The driver(s) below do not use LINUX_VERSION_CODE nor KERNEL_VERSION.
  arch/arm/plat-mxc/clock.c

This patch removes the said #include <version.h>.

Signed-off-by: Huang Weiyi <weiyi.huang@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-04 10:47:14 +01:00
Russell King c3df1a2685 [ARM] omap: fix build error in ohci-omap.c
drivers/usb/host/ohci-omap.c: In function 'ohci_omap_init':
drivers/usb/host/ohci-omap.c:228: error: 'start_hnp' undeclared (first use in this function)

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-04 09:45:47 +01:00
Linus Torvalds 5f17cfce57 PCI: fix pbus_size_mem() resource alignment for CardBus controllers
Commit 884525655d ("PCI: clean up resource
alignment management") changed the resource handling to mark how a
resource was aligned on a per-resource basis.

Thus, instead of looking at the resource number to determine whether it
was a bridge resource or a regular resource (they have different
alignment rules), we should just ask the resource for its alignment
directly.

The reason this broke only cardbus resources was that for the other
types of resources, the old way of deciding alignment actually still
happened to work.  But CardBus bridge resources had been changed by
commit 934b7024f0 ("Fix cardbus resource
allocation") to look more like regular resources than PCI bridge
resources from an alignment handling standpoint.

Reported-and-tested-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-04 01:33:59 -07:00
Gerrit Renker a3cbdde8e9 dccp ccid-3: Preventing Oscillations
This implements [RFC 3448, 4.5], which performs congestion avoidance behaviour
by reducing the transmit rate as the queueing delay (measured in terms of
long-term RTT) increases.

Oscillation can be turned on/off via a module option (do_osc_prev) and via sysfs
(using mode 0644), the default is off.

Overflow analysis:
------------------
 * oscillation prevention is done after update_x(), so that t_ipi <= 64000;
 * hence the multiplication "t_ipi * sqrt(R_sample)" needs 64 bits;
 * done using u64 for sqrt_sample and explicit typecast of t_ipi;
 * the divisor, R_sqmean, is non-zero because oscillation prevention is first
   called when receiving the second feedback packet, and tfrc_scaled_rtt() > 0.

A detailed discussion of the algorithm (with plots) is on
http://www.erg.abdn.ac.uk/users/gerrit/dccp/notes/ccid3/sender_notes/oscillation_prevention/

The algorithm has negative side effects:
  * when allowing to decrease t_ipi (leads to a large RTT) and
  * when using it during slow-start;
both uses are therefore disabled.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2008-09-04 07:45:43 +02:00