| Age | Commit message (Collapse) | Author |
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If we fail to create our mmu notification, we report the error back and
currently store the error inside the i915_mm_struct. This not only causes
subsequent registerations of the same mm to fail (an issue if the first
was interrupted by a signal and needed to be restarted) but also causes
us to eventually try and free the error pointer.
[ 73.419599] BUG: unable to handle kernel NULL pointer dereference at 000000000000004c
[ 73.419831] IP: [<ffffffff8114af33>] mmu_notifier_unregister+0x23/0x130
[ 73.420065] PGD 8650c067 PUD 870bb067 PMD 0
[ 73.420319] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
[ 73.420580] CPU: 0 PID: 42 Comm: kworker/0:1 Tainted: G W 3.17.0-rc6+ #1561
[ 73.420837] Hardware name: Intel Corporation SandyBridge Platform/LosLunas CRB, BIOS ASNBCPT1.86C.0075.P00.1106281639 06/28/2011
[ 73.421405] Workqueue: events __i915_mm_struct_free__worker
[ 73.421724] task: ffff880088a81220 ti: ffff880088168000 task.ti: ffff880088168000
[ 73.422051] RIP: 0010:[<ffffffff8114af33>] [<ffffffff8114af33>] mmu_notifier_unregister+0x23/0x130
[ 73.422410] RSP: 0018:ffff88008816bd50 EFLAGS: 00010286
[ 73.422765] RAX: 0000000000000003 RBX: ffff880086485400 RCX: 0000000000000000
[ 73.423137] RDX: ffff88016d80ee90 RSI: ffff880086485400 RDI: 0000000000000044
[ 73.423513] RBP: ffff88008816bd70 R08: 0000000000000001 R09: 0000000000000000
[ 73.423895] R10: 0000000000000320 R11: 0000000000000001 R12: 0000000000000044
[ 73.424282] R13: ffff880166e5f008 R14: ffff88016d815200 R15: ffff880166e5f040
[ 73.424682] FS: 0000000000000000(0000) GS:ffff88016d800000(0000) knlGS:0000000000000000
[ 73.425099] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 73.425537] CR2: 000000000000004c CR3: 0000000087f5f000 CR4: 00000000000407f0
[ 73.426157] Stack:
[ 73.426597] ffff880088a81248 ffff880166e5f038 fffffffffffffffc ffff880166e5f008
[ 73.427096] ffff88008816bd98 ffffffff814a75f2 ffff880166e5f038 ffff8800880f8a28
[ 73.427603] ffff88016d812ac0 ffff88008816be00 ffffffff8106321a ffffffff810631af
[ 73.428119] Call Trace:
[ 73.428606] [<ffffffff814a75f2>] __i915_mm_struct_free__worker+0x42/0x80
[ 73.429116] [<ffffffff8106321a>] process_one_work+0x1ba/0x610
[ 73.429632] [<ffffffff810631af>] ? process_one_work+0x14f/0x610
[ 73.430153] [<ffffffff810636db>] worker_thread+0x6b/0x4a0
[ 73.430671] [<ffffffff8108d67d>] ? trace_hardirqs_on+0xd/0x10
[ 73.431501] [<ffffffff81063670>] ? process_one_work+0x610/0x610
[ 73.432030] [<ffffffff8106a206>] kthread+0xf6/0x110
[ 73.432561] [<ffffffff8106a110>] ? __kthread_parkme+0x80/0x80
[ 73.433100] [<ffffffff8169c22c>] ret_from_fork+0x7c/0xb0
[ 73.433644] [<ffffffff8106a110>] ? __kthread_parkme+0x80/0x80
[ 73.434194] Code: 0f 1f 84 00 00 00 00 00 66 66 66 66 90 8b 46 4c 85 c0 0f 8e 10 01 00 00 55 48 89 e5 41 55 41 54 53 48 89 f3 49 89 fc 48 83 ec 08 <48> 83 7f 08 00 0f 84 b1 00 00 00 48 c7 c7 40 e6 ac 82 e8 26 65
[ 73.435942] RIP [<ffffffff8114af33>] mmu_notifier_unregister+0x23/0x130
[ 73.437017] RSP <ffff88008816bd50>
[ 73.437704] CR2: 000000000000004c
Fixes regression from commit ad46cb533d586fdb256855437af876617c6cf609
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date: Thu Aug 7 14:20:40 2014 +0100
drm/i915: Prevent recursive deadlock on releasing a busy userptr
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=84207
Testcase: igt/gem_render_copy_redux
Testcase: igt/gem_userptr_blits/create-destroy-sync
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jacek Danecki <jacek.danecki@intel.com>
Cc: "Gong, Zhipeng" <zhipeng.gong@intel.com>
Cc: Jacek Danecki <jacek.danecki@intel.com>
Cc: "Ursulin, Tvrtko" <tvrtko.ursulin@intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
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Stop brewing our own pin map reservation function and use the
generic code.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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This reverts commit c76bb61a71083b2d90504cc6d0dda2047c5d63ca.
It's apparently too broken so that Rodrigo submitted a patch to add a
config option for it. Given that the design is also ... suboptimal and
that I've only merged this to get lead engineers and managers off my
back for one second let's just revert this.
/me puts on combat gear again
It was worth a shot ...
References: http://mid.mail-archive.com/1411686380-1953-1-git-send-email-rodrigo.vivi@intel.com
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Daisy Sun <daisy.sun@intel.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
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sys_tz is already declared in include/linux/time.h
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jan Kara <jack@suse.cz>
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Export symbols from the PPMU driver needed to build the exynos bus
driver as a module.
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
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These functions are indended for use by drivers and should be available
also when the driver is built as a module.
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Ãrjan Eide <orjan.eide@arm.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
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Given following iptables ruleset:
-P FORWARD DROP
-A FORWARD -m sctp --dport 9 -j ACCEPT
-A FORWARD -p tcp --dport 80 -j ACCEPT
-A FORWARD -p tcp -m conntrack -m state ESTABLISHED,RELATED -j ACCEPT
One would assume that this allows SCTP on port 9 and TCP on port 80.
Unfortunately, if the SCTP conntrack module is not loaded, this allows
*all* SCTP communication, to pass though, i.e. -p sctp -j ACCEPT,
which we think is a security issue.
This is because on the first SCTP packet on port 9, we create a dummy
"generic l4" conntrack entry without any port information (since
conntrack doesn't know how to extract this information).
All subsequent packets that are unknown will then be in established
state since they will fallback to proto_generic and will match the
'generic' entry.
Our originally proposed version [1] completely disabled generic protocol
tracking, but Jozsef suggests to not track protocols for which a more
suitable helper is available, hence we now mitigate the issue for in
tree known ct protocol helpers only, so that at least NAT and direction
information will still be preserved for others.
[1] http://www.spinics.net/lists/netfilter-devel/msg33430.html
Joint work with Daniel Borkmann.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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The Kconfig symbol ARCH_HAS_OPP became redundant in v3.16: commit
049d595a4db3 ("PM / OPP: Make OPP invisible to users in Kconfig")
removed the only dependency that used it. Setting it had no effect
anymore.
So commit 78c5e0bb145d ("PM / OPP: Remove ARCH_HAS_OPP") removed it. For
some reason that commit did not remove all select statements for that
symbol. These statements are now useless. Remove one from devfreq too.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
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It is possible to turn off the card clock by setting
the frequency to zero via debugfs e.g.
echo 0 > /sys/kernel/debug/mmc0/clock
However that produces an incorrect warning that is
designed to warn if the frequency is below the minimum
operating frequency. So correct the warning.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
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We want to know in which cases the user explicitly sets the policy
options. In that case, we also want to dump back the info.
Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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mmc_gpiod_free_cd() is paired with mmc_gpiod_request_cd()
and both must reference the same device which is the
actual host controller device not the mmc_host class
device.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
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As of 528bc7808f4e ("mmc: atmel-mci: Release mmc resources on failure in probe"),
the atmci_probe() function calls atmci_cleanup_slot in the failure path.
This causes a new warning whenever the driver is built:
WARNING: drivers/mmc/host/built-in.o(.init.text+0xa04): Section mismatch in reference from the function atmci_probe() to the function .exit.text:atmci_cleanup_slot()
The function __init atmci_probe() references
a function __exit atmci_cleanup_slot().
Gcc correctly warns about this function getting dropped in the link stage
for the built-in case, which would cause undefined behavior when this error
path is hit. The solution is to simply drop the __exit annotation.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 528bc7808f4e ("mmc: atmel-mci: Release mmc resources on failure in probe")
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
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It is safe to call the pm sync calls in interrupt context in this driver.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>
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As written, the __init for ti_clk_get_div_table is in the middle of the return
type.
The gcc documentation indicates that section attributes should be added to the
end of the function declaration:
extern void foobar (void) __attribute__ ((section ("bar")));
However gcc seems to be very permissive with where attributes can be placed.
clang on the other hand isn't so permissive, and fails if you put the section
definition in the middle of the return type:
drivers/clk/ti/divider.c:298:28: error: expected ';' after struct
static struct clk_div_table
^
;
drivers/clk/ti/divider.c:298:1: warning: 'static' ignored on this
declaration [-Wmissing-declarations]
static struct clk_div_table
^
drivers/clk/ti/divider.c:299:9: error: type specifier missing,
defaults to 'int' [-Werror,-Wimplicit-int]
__init *ti_clk_get_div_table(struct device_node *node)
~~~~~~ ^
drivers/clk/ti/divider.c:345:9: warning: incompatible pointer types
returning 'struct clk_div_table *' from a function with result type 'int *' [-Wincompatible-pointer-types]
return table;
^~~~~
drivers/clk/ti/divider.c:419:9: warning: incompatible pointer types
assigning to 'const struct clk_div_table *' from 'int *' [-Wincompatible-pointer-types]
*table = ti_clk_get_div_table(node);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~
3 warnings and 2 errors generated.
By convention, most of the kernel code puts section attributes between the
return type and function name. In the case where the return type is a pointer,
it's important to place the '*' on left of the __init.
This updated code works for both gcc and clang.
Signed-off-by: Behan Webster <behanw@converseincode.com>
Reviewed-by: Mark Charlebois <charlebm@gmail.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>
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I "forgot" to update the dtb and the kernel crashed:
|Unable to handle kernel NULL pointer dereference at virtual address 0000002e
|PC is at __clk_get_flags+0x4/0xc
|LR is at ti_dt_clockdomains_setup+0x70/0xe8
because I did not have the clock nodes. of_clk_get() returns an error
pointer which is not checked here.
Acked-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Tero Kristo <t-kristo@ti.com>
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of_clk_add_provider makes an internal copy of the parent_names property
while its called, thus it is no longer needed after this call and can
be freed.
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
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Previously, the TI clock driver initialized all the clocks hierarchically
under each separate clock provider node. Now, each clock that requires
IO access will instead check their parent node to find out which IO range
to use.
This patch allows the TI clock driver to use a few new features provided
by the generic of_clk_init, and also allows registration of clock nodes
outside the clock hierarchy (for example, any external clocks.)
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: Jyri Sarha <jsarha@ti.com>
Cc: Stefan Assmann <sassmann@kpanic.de>
Acked-by: Tony Lindgren <tony@atomide.com>
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We need to make sure that the saved skb exists when
resuming or suspending a CoC channel. This can happen if
initial credits is 0 when channel is connected.
Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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Stefan Wahren says:
====================
add Qualcomm QCA7000 ethernet driver
This patch series adds support for the Qualcomm QCA7000 Homeplug GreenPHY.
The QCA7000 is serial-to-powerline bridge with two interfaces: UART and SPI.
These patches handles only the last one, with an Ethernet over SPI protocol
driver.
This driver based on the Qualcomm code [1], but contains a lot of changes
since last year:
* devicetree support
* DebugFS support
* ethtool support
* better error handling
* performance improvements
* code cleanup
* some bugfixes
The code has been tested only on Freescale i.MX28 boards, but should work
on other platforms.
[1] - https://github.com/IoE/qca7000
Changes in V3:
- Use ether_addr_copy instead of memcpy
- Remove qcaspi_set_mac_address
- Improve DT parsing
- replace OF_GPIO dependancy with OF
- fix compile error caused by SET_ETHTOOL_OPS
- fix possible endless loop when spi read fails
- fix DT documentation
- fix coding style
- fix sparse warnings
Changes in V2:
- replace in DT the SPI intr GPIO with pure interrupt
- make legacy mode a boolean DT property and remove it as module parameter
- make burst length a module parameter instead of DT property
- make pluggable a module parameter instead of DT property
- improve DT documentation
- replace debugFS register dump with ethtool function
- replace debugFS stats with ethtool function
- implement function to get ring parameter via ethtool
- implement function to set TX ring count via ethtool
- fix TX ring state in debugFS
- optimize tx ring flush
- add byte limit for TX ring to avoid bufferbloat
- fix TX queue full and write buffer miss counter
- fix SPI clk speed module parameter
- fix possible packet loss
- fix possible race during transmit
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch adds the Ethernet over SPI driver for the
Qualcomm QCA7000 HomePlug GreenPHY.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch adds the Device tree bindings for the
Ethernet over SPI protocol driver of the Qualcomm
QCA7000 HomePlug GreenPHY.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Daniel Borkmann says:
====================
net: tcp: DCTCP congestion control algorithm
This patch series adds support for the DataCenter TCP (DCTCP) congestion
control algorithm. Please see individual patches for the details.
The last patch adds DCTCP as a congestion control module, and previous
ones add needed infrastructure to extend the congestion control framework.
Joint work between Florian Westphal, Daniel Borkmann and Glenn Judd.
v3 -> v2:
- No changes anywhere, just a resend as requested by Dave
- Added Stephen's ACK
v1 -> v2:
- Rebased to latest net-next
- Addressed Eric's feedback, thanks!
- Update stale comment wrt. DCTCP ECN usage
- Don't call INET_ECN_xmit for every packet
- Add dctcp ss/inetdiag support to expose internal stats to userspace
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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This work adds the DataCenter TCP (DCTCP) congestion control
algorithm [1], which has been first published at SIGCOMM 2010 [2],
resp. follow-up analysis at SIGMETRICS 2011 [3] (and also, more
recently as an informational IETF draft available at [4]).
DCTCP is an enhancement to the TCP congestion control algorithm for
data center networks. Typical data center workloads are i.e.
i) partition/aggregate (queries; bursty, delay sensitive), ii) short
messages e.g. 50KB-1MB (for coordination and control state; delay
sensitive), and iii) large flows e.g. 1MB-100MB (data update;
throughput sensitive). DCTCP has therefore been designed for such
environments to provide/achieve the following three requirements:
* High burst tolerance (incast due to partition/aggregate)
* Low latency (short flows, queries)
* High throughput (continuous data updates, large file
transfers) with commodity, shallow buffered switches
The basic idea of its design consists of two fundamentals: i) on the
switch side, packets are being marked when its internal queue
length > threshold K (K is chosen so that a large enough headroom
for marked traffic is still available in the switch queue); ii) the
sender/host side maintains a moving average of the fraction of marked
packets, so each RTT, F is being updated as follows:
F := X / Y, where X is # of marked ACKs, Y is total # of ACKs
alpha := (1 - g) * alpha + g * F, where g is a smoothing constant
The resulting alpha (iow: probability that switch queue is congested)
is then being used in order to adaptively decrease the congestion
window W:
W := (1 - (alpha / 2)) * W
The means for receiving marked packets resp. marking them on switch
side in DCTCP is the use of ECN.
RFC3168 describes a mechanism for using Explicit Congestion Notification
from the switch for early detection of congestion, rather than waiting
for segment loss to occur.
However, this method only detects the presence of congestion, not
the *extent*. In the presence of mild congestion, it reduces the TCP
congestion window too aggressively and unnecessarily affects the
throughput of long flows [4].
DCTCP, as mentioned, enhances Explicit Congestion Notification (ECN)
processing to estimate the fraction of bytes that encounter congestion,
rather than simply detecting that some congestion has occurred. DCTCP
then scales the TCP congestion window based on this estimate [4],
thus it can derive multibit feedback from the information present in
the single-bit sequence of marks in its control law. And thus act in
*proportion* to the extent of congestion, not its *presence*.
Switches therefore set the Congestion Experienced (CE) codepoint in
packets when internal queue lengths exceed threshold K. Resulting,
DCTCP delivers the same or better throughput than normal TCP, while
using 90% less buffer space.
It was found in [2] that DCTCP enables the applications to handle 10x
the current background traffic, without impacting foreground traffic.
Moreover, a 10x increase in foreground traffic did not cause any
timeouts, and thus largely eliminates TCP incast collapse problems.
The algorithm itself has already seen deployments in large production
data centers since then.
We did a long-term stress-test and analysis in a data center, short
summary of our TCP incast tests with iperf compared to cubic:
This test measured DCTCP throughput and latency and compared it with
CUBIC throughput and latency for an incast scenario. In this test, 19
senders sent at maximum rate to a single receiver. The receiver simply
ran iperf -s.
The senders ran iperf -c <receiver> -t 30. All senders started
simultaneously (using local clocks synchronized by ntp).
This test was repeated multiple times. Below shows the results from a
single test. Other tests are similar. (DCTCP results were extremely
consistent, CUBIC results show some variance induced by the TCP timeouts
that CUBIC encountered.)
For this test, we report statistics on the number of TCP timeouts,
flow throughput, and traffic latency.
1) Timeouts (total over all flows, and per flow summaries):
CUBIC DCTCP
Total 3227 25
Mean 169.842 1.316
Median 183 1
Max 207 5
Min 123 0
Stddev 28.991 1.600
Timeout data is taken by measuring the net change in netstat -s
"other TCP timeouts" reported. As a result, the timeout measurements
above are not restricted to the test traffic, and we believe that it
is likely that all of the "DCTCP timeouts" are actually timeouts for
non-test traffic. We report them nevertheless. CUBIC will also include
some non-test timeouts, but they are drawfed by bona fide test traffic
timeouts for CUBIC. Clearly DCTCP does an excellent job of preventing
TCP timeouts. DCTCP reduces timeouts by at least two orders of
magnitude and may well have eliminated them in this scenario.
2) Throughput (per flow in Mbps):
CUBIC DCTCP
Mean 521.684 521.895
Median 464 523
Max 776 527
Min 403 519
Stddev 105.891 2.601
Fairness 0.962 0.999
Throughput data was simply the average throughput for each flow
reported by iperf. By avoiding TCP timeouts, DCTCP is able to
achieve much better per-flow results. In CUBIC, many flows
experience TCP timeouts which makes flow throughput unpredictable and
unfair. DCTCP, on the other hand, provides very clean predictable
throughput without incurring TCP timeouts. Thus, the standard deviation
of CUBIC throughput is dramatically higher than the standard deviation
of DCTCP throughput.
Mean throughput is nearly identical because even though cubic flows
suffer TCP timeouts, other flows will step in and fill the unused
bandwidth. Note that this test is something of a best case scenario
for incast under CUBIC: it allows other flows to fill in for flows
experiencing a timeout. Under situations where the receiver is issuing
requests and then waiting for all flows to complete, flows cannot fill
in for timed out flows and throughput will drop dramatically.
3) Latency (in ms):
CUBIC DCTCP
Mean 4.0088 0.04219
Median 4.055 0.0395
Max 4.2 0.085
Min 3.32 0.028
Stddev 0.1666 0.01064
Latency for each protocol was computed by running "ping -i 0.2
<receiver>" from a single sender to the receiver during the incast
test. For DCTCP, "ping -Q 0x6 -i 0.2 <receiver>" was used to ensure
that traffic traversed the DCTCP queue and was not dropped when the
queue size was greater than the marking threshold. The summary
statistics above are over all ping metrics measured between the single
sender, receiver pair.
The latency results for this test show a dramatic difference between
CUBIC and DCTCP. CUBIC intentionally overflows the switch buffer
which incurs the maximum queue latency (more buffer memory will lead
to high latency.) DCTCP, on the other hand, deliberately attempts to
keep queue occupancy low. The result is a two orders of magnitude
reduction of latency with DCTCP - even with a switch with relatively
little RAM. Switches with larger amounts of RAM will incur increasing
amounts of latency for CUBIC, but not for DCTCP.
4) Convergence and stability test:
This test measured the time that DCTCP took to fairly redistribute
bandwidth when a new flow commences. It also measured DCTCP's ability
to remain stable at a fair bandwidth distribution. DCTCP is compared
with CUBIC for this test.
At the commencement of this test, a single flow is sending at maximum
rate (near 10 Gbps) to a single receiver. One second after that first
flow commences, a new flow from a distinct server begins sending to
the same receiver as the first flow. After the second flow has sent
data for 10 seconds, the second flow is terminated. The first flow
sends for an additional second. Ideally, the bandwidth would be evenly
shared as soon as the second flow starts, and recover as soon as it
stops.
The results of this test are shown below. Note that the flow bandwidth
for the two flows was measured near the same time, but not
simultaneously.
DCTCP performs nearly perfectly within the measurement limitations
of this test: bandwidth is quickly distributed fairly between the two
flows, remains stable throughout the duration of the test, and
recovers quickly. CUBIC, in contrast, is slow to divide the bandwidth
fairly, and has trouble remaining stable.
CUBIC DCTCP
Seconds Flow 1 Flow 2 Seconds Flow 1 Flow 2
0 9.93 0 0 9.92 0
0.5 9.87 0 0.5 9.86 0
1 8.73 2.25 1 6.46 4.88
1.5 7.29 2.8 1.5 4.9 4.99
2 6.96 3.1 2 4.92 4.94
2.5 6.67 3.34 2.5 4.93 5
3 6.39 3.57 3 4.92 4.99
3.5 6.24 3.75 3.5 4.94 4.74
4 6 3.94 4 5.34 4.71
4.5 5.88 4.09 4.5 4.99 4.97
5 5.27 4.98 5 4.83 5.01
5.5 4.93 5.04 5.5 4.89 4.99
6 4.9 4.99 6 4.92 5.04
6.5 4.93 5.1 6.5 4.91 4.97
7 4.28 5.8 7 4.97 4.97
7.5 4.62 4.91 7.5 4.99 4.82
8 5.05 4.45 8 5.16 4.76
8.5 5.93 4.09 8.5 4.94 4.98
9 5.73 4.2 9 4.92 5.02
9.5 5.62 4.32 9.5 4.87 5.03
10 6.12 3.2 10 4.91 5.01
10.5 6.91 3.11 10.5 4.87 5.04
11 8.48 0 11 8.49 4.94
11.5 9.87 0 11.5 9.9 0
SYN/ACK ECT test:
This test demonstrates the importance of ECT on SYN and SYN-ACK packets
by measuring the connection probability in the presence of competing
flows for a DCTCP connection attempt *without* ECT in the SYN packet.
The test was repeated five times for each number of competing flows.
Competing Flows 1 | 2 | 4 | 8 | 16
------------------------------
Mean Connection Probability 1 | 0.67 | 0.45 | 0.28 | 0
Median Connection Probability 1 | 0.65 | 0.45 | 0.25 | 0
As the number of competing flows moves beyond 1, the connection
probability drops rapidly.
Enabling DCTCP with this patch requires the following steps:
DCTCP must be running both on the sender and receiver side in your
data center, i.e.:
sysctl -w net.ipv4.tcp_congestion_control=dctcp
Also, ECN functionality must be enabled on all switches in your
data center for DCTCP to work. The default ECN marking threshold (K)
heuristic on the switch for DCTCP is e.g., 20 packets (30KB) at
1Gbps, and 65 packets (~100KB) at 10Gbps (K > 1/7 * C * RTT, [4]).
In above tests, for each switch port, traffic was segregated into two
queues. For any packet with a DSCP of 0x01 - or equivalently a TOS of
0x04 - the packet was placed into the DCTCP queue. All other packets
were placed into the default drop-tail queue. For the DCTCP queue,
RED/ECN marking was enabled, here, with a marking threshold of 75 KB.
More details however, we refer you to the paper [2] under section 3).
There are no code changes required to applications running in user
space. DCTCP has been implemented in full *isolation* of the rest of
the TCP code as its own congestion control module, so that it can run
without a need to expose code to the core of the TCP stack, and thus
nothing changes for non-DCTCP users.
Changes in the CA framework code are minimal, and DCTCP algorithm
operates on mechanisms that are already available in most Silicon.
The gain (dctcp_shift_g) is currently a fixed constant (1/16) from
the paper, but we leave the option that it can be chosen carefully
to a different value by the user.
In case DCTCP is being used and ECN support on peer site is off,
DCTCP falls back after 3WHS to operate in normal TCP Reno mode.
ss {-4,-6} -t -i diag interface:
... dctcp wscale:7,7 rto:203 rtt:2.349/0.026 mss:1448 cwnd:2054
ssthresh:1102 ce_state 0 alpha 15 ab_ecn 0 ab_tot 735584
send 10129.2Mbps pacing_rate 20254.1Mbps unacked:1822 retrans:0/15
reordering:101 rcv_space:29200
... dctcp-reno wscale:7,7 rto:201 rtt:0.711/1.327 ato:40 mss:1448
cwnd:10 ssthresh:1102 fallback_mode send 162.9Mbps pacing_rate
325.5Mbps rcv_rtt:1.5 rcv_space:29200
More information about DCTCP can be found in [1-4].
[1] http://simula.stanford.edu/~alizade/Site/DCTCP.html
[2] http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp-final.pdf
[3] http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp_analysis-full.pdf
[4] http://tools.ietf.org/html/draft-bensley-tcpm-dctcp-00
Joint work with Florian Westphal and Glenn Judd.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Glenn Judd <glenn.judd@morganstanley.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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DataCenter TCP (DCTCP) determines cwnd growth based on ECN information
and ACK properties, e.g. ACK that updates window is treated differently
than DUPACK.
Also DCTCP needs information whether ACK was delayed ACK. Furthermore,
DCTCP also implements a CE state machine that keeps track of CE markings
of incoming packets.
Therefore, extend the congestion control framework to provide these
event types, so that DCTCP can be properly implemented as a normal
congestion algorithm module outside of the core stack.
Joint work with Daniel Borkmann and Glenn Judd.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Glenn Judd <glenn.judd@morganstanley.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The congestion control ops "cwnd_event" currently supports
CA_EVENT_FAST_ACK and CA_EVENT_SLOW_ACK events (among others).
Both FAST and SLOW_ACK are only used by Westwood congestion
control algorithm.
This removes both flags from cwnd_event and adds a new
in_ack_event callback for this. The goal is to be able to
provide more detailed information about ACKs, such as whether
ECE flag was set, or whether the ACK resulted in a window
update.
It is required for DataCenter TCP (DCTCP) congestion control
algorithm as it makes a different choice depending on ECE being
set or not.
Joint work with Daniel Borkmann and Glenn Judd.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Glenn Judd <glenn.judd@morganstanley.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch adds a flag to TCP congestion algorithms that allows
for requesting to mark IPv4/IPv6 sockets with transport as ECN
capable, that is, ECT(0), when required by a congestion algorithm.
It is currently used and needed in DataCenter TCP (DCTCP), as it
requires both peers to assert ECT on all IP packets sent - it
uses ECN feedback (i.e. CE, Congestion Encountered information)
from switches inside the data center to derive feedback to the
end hosts.
Therefore, simply add a new flag to icsk_ca_ops. Note that DCTCP's
algorithm/behaviour slightly diverges from RFC3168, therefore this
is only (!) enabled iff the assigned congestion control ops module
has requested this. By that, we can tightly couple this logic really
only to the provided congestion control ops.
Joint work with Florian Westphal and Glenn Judd.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Glenn Judd <glenn.judd@morganstanley.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Split assignment and initialization from one into two functions.
This is required by followup patches that add Datacenter TCP
(DCTCP) congestion control algorithm - we need to be able to
determine if the connection is moderated by DCTCP before the
3WHS has finished.
As we walk the available congestion control list during the
assignment, we are always guaranteed to have Reno present as
it's fixed compiled-in. Therefore, since we're doing the
early assignment, we don't have a real use for the Reno alias
tcp_init_congestion_ops anymore and can thus remove it.
Actual usage of the congestion control operations are being
made after the 3WHS has finished, in some cases however we
can access get_info() via diag if implemented, therefore we
need to zero out the private area for those modules.
Joint work with Daniel Borkmann and Glenn Judd.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Glenn Judd <glenn.judd@morganstanley.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This completes the cls_rsvp conversion to RCU safe
copy, update semantics.
As a result all cases of tcf_exts_change occur on
empty lists now.
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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While doing high throughput test on a BQL enabled NIC,
I found a very high cost in ndo_start_xmit() when accessing BQL data.
It turned out the problem was caused by compiler trying to be
smart, but involving a bad MESI transaction :
0.05 │ mov 0xc0(%rax),%edi // LOAD dql->num_queued
0.48 │ mov %edx,0xc8(%rax) // STORE dql->last_obj_cnt = count
58.23 │ add %edx,%edi
0.58 │ cmp %edi,0xc4(%rax)
0.76 │ mov %edi,0xc0(%rax) // STORE dql->num_queued += count
0.72 │ js bd8
I got an incredible 10 % gain [1] by making sure cpu do not attempt
to get the cache line in Shared mode, but directly requests for
ownership.
New code :
mov %edx,0xc8(%rax) // STORE dql->last_obj_cnt = count
add %edx,0xc0(%rax) // RMW dql->num_queued += count
mov 0xc4(%rax),%ecx // LOAD dql->adj_limit
mov 0xc0(%rax),%edx // LOAD dql->num_queued
cmp %edx,%ecx
The TX completion was running from another cpu, with high interrupts
rate.
Note that I am using barrier() as a soft hint, as mb() here could be
too heavy cost.
[1] This was a netperf TCP_STREAM with TSO disabled, but GSO enabled.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch fixes this sparse warning:
drivers/staging/rtl8192u/ieee80211/ieee80211_crypt_ccmp.c:60:6: warning:
symbol 'ieee80211_ccmp_aes_encrypt' was not declared. Should it be static?
Signed-off-by: Aybuke Ozdemir <aybuke.147@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Fix the following checkpatch.pl warning:
WARNING: Missing a blank line after declarations
Signed-off-by: Georgiana Chelu <georgiana.chelu93@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch removes a variable which has never been used. The following
Coccinelle semantic patch was used to make this transformation:
@@
type T;
identifier i;
constant C;
@@
- T i;
<... when != i
- i = C;
...>
Signed-off-by: Mahati Chamarthy <mahati.chamarthy@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The following patch fixes the checkpatch.pl error:
ERROR: trailing whitespace
Signed-off-by: Esra Altintas <es.altintas@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This fixes the checkpatch.pl error:
ERROR: space prohibited before that close parenthesis ')'
Signed-off-by: Roxana Blaj <roxanagabriela10@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This fixes the checkpatch.pl warning:
WARNING: space prohibited before semicolon
Signed-off-by: Roxana Blaj <roxanagabriela10@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This fixes the checkpatch.pl error:
ERROR: space required after that close brace '}'
Signed-off-by: Roxana Blaj <roxanagabriela10@gmail.com>
Acked-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This fixes "void function return statements are not generally useful"
checkpatch.pl warning slicoss.c
Signed-off-by: Dilek Uzulmez <dilekuzulmez@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This fixes the checkpatch.pl error:
ERROR: space required before the open parenthesis '('
Signed-off-by: Roxana Blaj <roxanagabriela10@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch removes an initialized variable which has never been used.
The following Coccinelle semantic patch was used to make this transformation:
@e@
identifier i;
position p;
type T;
@@
extern T i@p;
@@
type T;
identifier i;
constant C;
position p != e.p;
@@
- T i@p;
<+... when != i
- i = C;
...+>
The braces around if and else which become unnecessary after the transformation
were also removed.
Signed-off-by: Mahati Chamarthy <mahati.chamarthy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Fixes "Missing a blank line after declarations" checkpatch.pl warning in
ethernet-rgmii.c
Signed-off-by: Melike Yurtoglu <aysemelikeyurtoglu@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch fixes "else is not generally useful after a break or return"
checkpatch.pl warning ethernet-util.h
Signed-off-by: Dilek Uzulmez <dilekuzulmez@gmail.com>
Acked-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The following patch fixes the checpatch.pl warning:
WARNING: line over 80 characters
Signed-off-by: Esra Altintas <es.altintas@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch fixes "braces {} are not necessary for single statement
blocks" checkpatch.pl warning in netlink_k.c
Signed-off-by: Gulsah Kose <gulsah.1004@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch fixes "else is not generally useful after a break or return"
checkpatch.pl warning in netlink_k.c
Signed-off-by: Gulsah Kose <gulsah.1004@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch fixes "else is not generally useful after a break or return"
checkpatch.pl warning in gdm_usb.c
Signed-off-by: Gulsah Kose <gulsah.1004@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch fixes checkpatch.pl error in file ft1000_hw.c
ERROR: space required after that ';' (ctx:VxV)
Signed-off-by: Aybuke Ozdemir <aybuke.147@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch fixes "Use #include <linux/uaccess.h> instead of
<asm/uaccess.h" checkpatch.pl warning in ft1000_dnld.c
Signed-off-by: Gulsah Kose <gulsah.1004@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch fixes "else is not generally useful after a break or return"
checkpatch.pl warning in ft1000_dnld.c
Signed-off-by: Gulsah Kose <gulsah.1004@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This fixes the checkpatch.pl warning:
WARNING: macros should not use a trailing semicolon.
Signed-off-by: Aybuke Ozdemir <aybuke.147@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch merges three lines into one, removing unecessary
if check.
Signed-off-by: Tapasweni Pathak <tapaswenipathak@gmail.com>
Reviewed-by: Himangi Saraogi <himangi774@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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