Under memory pressure, tcp_sendmsg() can fail to queue a packet
while no packet is present in write queue. If we return -EAGAIN
with no packet in write queue, no ACK packet will ever come
to raise EPOLLOUT.
We need to allow one skb per TCP socket, and make sure that
tcp sockets can release their forward allocations under pressure.
This is a followup to commit 790ba4566c ("tcp: set SOCK_NOSPACE
under memory pressure")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Introduce an optimized version of sk_under_memory_pressure()
for TCP. Our intent is to use it in fast paths.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We plan to use sk_forced_wmem_schedule() in input path as well,
so make it non static and rename it.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sk_mem_reclaim_partial() goal is to ensure each socket has
one SK_MEM_QUANTUM forward allocation. This is needed both for
performance and better handling of memory pressure situations in
follow up patches.
SK_MEM_QUANTUM is currently a page, but might be reduced to 4096 bytes
as some arches have 64KB pages.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rollover can be enabled as flag or mode. Allocate state in both cases.
This solves a NULL pointer exception in fanout_demux_rollover on
referencing po->rollover if using mode rollover.
Also make sure that in rollover mode each silo is tried (contrary
to rollover flag, where the main socket is excluded after an initial
try_self).
Tested:
Passes tools/testing/net/psock_fanout.c, which tests both modes and
flag. My previous tests were limited to bench_rollover, which only
stresses the flag. The test now completes safely. it still gives an
error for mode rollover, because it does not expect the new headroom
(ROOM_NORMAL) requirement. I will send a separate patch to the test.
Fixes: 0648ab70af ("packet: rollover prepare: per-socket state")
Signed-off-by: Willem de Bruijn <willemb@google.com>
----
I should have run this test and caught this before submission, of
course. Apologies for the oversight.
Signed-off-by: David S. Miller <davem@davemloft.net>
First one in __skb_checksum_validate_complete() fixes the following
(and other callers)
make C=2 CF=-D__CHECK_ENDIAN__ net/ipv4/tcp_ipv4.o
CHECK net/ipv4/tcp_ipv4.c
include/linux/skbuff.h:3052:24: warning: incorrect type in return expression (different base types)
include/linux/skbuff.h:3052:24: expected restricted __sum16
include/linux/skbuff.h:3052:24: got int
Second is fixing gso_make_checksum() :
CHECK net/ipv4/gre_offload.c
include/linux/skbuff.h:3360:14: warning: incorrect type in assignment (different base types)
include/linux/skbuff.h:3360:14: expected unsigned short [unsigned] [usertype] csum
include/linux/skbuff.h:3360:14: got restricted __sum16
include/linux/skbuff.h:3365:16: warning: incorrect type in return expression (different base types)
include/linux/skbuff.h:3365:16: expected restricted __sum16
include/linux/skbuff.h:3365:16: got unsigned short [unsigned] [usertype] csum
Fixes: 5a21232983 ("net: Support for csum_bad in skbuff")
Fixes: 7e2b10c1e5 ("net: Support for multiple checksums with gso")
Signed-off-by: Eric Dumazet <edumazet@google.com>
CC: Tom Herbert <tom@herbertland.com>
Acked-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix verbose sparse errors :
make C=2 CF=-D__CHECK_ENDIAN__ net/ipv4/netfilter/ipt_SYNPROXY.o
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
make C=2 CF=-D__CHECK_ENDIAN__ net/ipv4/ipip.o
CHECK net/ipv4/ipip.c
net/ipv4/ipip.c:254:27: warning: incorrect type in assignment (different base types)
net/ipv4/ipip.c:254:27: expected restricted __be32 [addressable] [usertype] o_key
net/ipv4/ipip.c:254:27: got restricted __be16 [addressable] [usertype] i_flags
Fixes: 3b7b514f44 ("ipip: fix a regression in ioctl")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It can be useful to debug the PHY state machine, add dynamic debug
prints of the old and new PHY devices state under a friendly format.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Once we get a neighbour through looking up arp cache or creating a
new one in rocker_port_ipv4_resolve(), the neighbour's refcount is
already taken. But as we don't put the refcount again after it's
used, this makes the neighbour entry leaked.
Suggested-by: Eric Dumazet <edumazet@google.com>
Acked-by: Jiri Pirko <jiri@resnulli.us>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Acked-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
Tom Lendacky says:
====================
amd-xgbe: AMD XGBE driver updates 2015-05-12
The following series of patches includes functional updates and changes
to the driver.
- Add additional statistics to be collected and reported
- Use the netif_* functions for issuing some debug and informational
driver messages
- Rx path SKB allocation cleanup/simplification
- Remove stand-alone phylib driver and incorporate function into the nic
driver
- Simplify device tree support while maintaining backwards compatibility
- Fix the flow control negotiation logic to properly configure flow
control
- Remove the checking and setting of the device dma_mask field
This patch series is based on net-next.
Changes in v2:
- Change from using the netif_msg_*/netdev_* combination for issuing
messages to the more concise netif_*
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
The underlying device support will set the device dma_mask pointer
if DMA is set up properly for the device. Remove the check for and
assignment of dma_mask when it is null. Instead, just error out if
the dma_set_mask_and_coherent function fails because dma_mask is null.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The flow control negotiation logic is flawed and does not properly
advertise and process auto-negotiation of the flow control settings.
Update the flow control support to properly set the flow control
auto-negotiation settings and process the results approrpriately.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Simplify the device tree support of the amd-xgbe driver by defining
the PHY-related resources within the ethernet device node. The support
provides backwards compatibility with the original way.
Update the driver version to 1.0.2.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The AMD XGBE device is intended to work with a specific integrated PHY
and that PHY is not meant to be a standalone PHY for use by other
devices. As such this patch removes the phylib driver and implements
the PHY support in the amd-xgbe driver (the majority of the logic from
the phylib driver is moved into the amd-xgbe driver).
Update the driver version to 1.0.1.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rework the SKB allocation so that all of the buffers of the first
descriptor are handled in the SKB allocation routine. After copying the
data in the header buffer (which can be just the header if split header
processing succeeded for header plus data if split header processing did
not succeed) into the SKB, check for remaining data in the receive
buffer. If there is data remaining in the receive buffer, add that as a
frag to the SKB. Once an SKB has been allocated, all other descriptors
are added as frags to the SKB.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for the network interface message level settings for
determining whether to issue some of the driver messages. Make
use of the netif_* interface where appropriate.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add additional/extended statistics beyond what is provided by the
hardware to be reported via ethtool. The new stats focus on the
calls into ndo_start_xmit and the napi_poll routine.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Joachim Eastwood says:
====================
convert stmmac glue layers into platform drivers
This patch set aims to convert the current dwmac glue layers into
proper platform drivers as request by Arnd[1]. These changes start
from patch 3 and onwards.
Overview:
Platform driver functions like probe and remove are exported from
the stmmac platform and then used in subsequent glue later
conversions. The conversion involes adding the platform driver
boiler plate code and adding it to the build system. The last patch
removes the driver from the stmmac platform code thus making it into
a library for common platform driver functions.
The two first patches adds glue layer for my platform. I chose to
first add old style glue layer and then convert it. The churn this
creates is just 3 lines.
I would be very nice if people could test this patch set on their
respective platform. My testing has been limited to compiling and
testing on my (LPC18xx) platform. Thanks!
Next I will look into cleaning up the stmmac platform code.
[1] http://marc.info/?l=linux-arm-kernel&m=143059524606459&w=2
====================
Tested-by: Chen-Yu Tsai <wens@csie.org>
Tested-by: Dinh Nguyen <dinguyen@opensource.altera.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The dwmac-generic replaces the driver inside the stmmac
platform code. This turns stmmac platform into a library
used by drivers for common platform driver functions.
Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Convert platform glue layer into a proper platform
driver and add it to the build system.
Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Convert platform glue layer into a proper platform
driver and add it to the build system.
Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Convert platform glue layer into a proper platform
driver and add it to the build system.
Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Convert platform glue layer into a proper platform
driver and add it to the build system.
Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Convert platform glue layer into a proper platform
driver and add it to the build system.
Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Convert platform glue layer into a proper platform
driver and add it to the build system.
Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Create a new driver around the generic device tree match strings
in the stmmac platform code. This driver is intended to be used
by all platforms that doesn't require any platform specific code
to function or is using platform data.
Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Prepare the stmmac platform code to support standalone drivers
by exporting the need functions and having of_match_device use
the match table reference already present in the driver struct.
This will allow us to reuse the platform driver functions from
this code easily in other stand alone platform drivers.
Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add device tree binding documentation for nxp,lpc1850-dwmac.
Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for Ethernet on NXP LPC18xx and LPC43xx using the
dwmac driver. This glue is required to setup phy interface
mode, MII or RMII, on the SoC.
Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Current code does not lock anything when calculating the TX and RX stats.
As a result, the RX and TX data reported by ifconfig are not accuracy in a
system with high network throughput and multiple CPUs (in my test,
RX/TX = 83% between 2 HyperV VM nodes which have 8 vCPUs and 40G Ethernet).
This patch fixed the above issue by using per_cpu stats.
netvsc_get_stats64() summarizes TX and RX data by iterating over all CPUs
to get their respective stats.
This v2 patch addressed David's comments on the cleanup path when
netdev_alloc_pcpu_stats() failed.
Signed-off-by: Simon Xiao <sixiao@microsoft.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix several sparse warnings like:
lib/test_bpf.c:1824:25: sparse: constant 4294967295 is so big it is long
lib/test_bpf.c:1878:25: sparse: constant 0x0000ffffffff0000 is so big it is long
Fixes: cffc642d93 ("test_bpf: add 173 new testcases for eBPF")
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
commit d2788d3488 ("net: sched: further simplify handle_ing")
removed the call to qdisc_enqueue_root().
However, after this removal we no longer set qdisc pkt length.
This breaks traffic policing on ingress.
This is the minimum fix: set qdisc pkt length before tc_classify.
Only setting the length does remove support for 'stab' on ingress, but
as Alexei pointed out:
"Though it was allowed to add qdisc_size_table to ingress, it's useless.
Nothing takes advantage of recomputed qdisc_pkt_len".
Jamal suggested to use qdisc_pkt_len_init(), but as Eric mentioned that
would result in qdisc_pkt_len_init to no longer get inlined due to the
additional 2nd call site.
ingress policing is rare and GRO doesn't really work that well with police
on ingress, as we see packets > mtu and drop skbs that -- without
aggregation -- would still have fitted the policier budget.
Thus to have reliable/smooth ingress policing GRO has to be turned off.
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Fixes: d2788d3488 ("net: sched: further simplify handle_ing")
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Unlock was missing on error path.
Fixes: 95f38411df ("netns: use a spin_lock to protect nsid management")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This also changes mii_bus.phy_mask to u32 for consistency.
Signed-off-by: Bert Vermeulen <bert@biot.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Couple of torture test cases related to the bug fixed in 0b59d8806a
("ARM: net: delegate filter to kernel interpreter when imm_offset()
return value can't fit into 12bits.").
I've added a helper to allocate and fill the insn space. Output on
x86_64 from my laptop:
test_bpf: #233 BPF_MAXINSNS: Maximum possible literals jited:0 7 PASS
test_bpf: #234 BPF_MAXINSNS: Single literal jited:0 8 PASS
test_bpf: #235 BPF_MAXINSNS: Run/add until end jited:0 11553 PASS
test_bpf: #236 BPF_MAXINSNS: Too many instructions PASS
test_bpf: #237 BPF_MAXINSNS: Very long jump jited:0 9 PASS
test_bpf: #238 BPF_MAXINSNS: Ctx heavy transformations jited:0 20329 20398 PASS
test_bpf: #239 BPF_MAXINSNS: Call heavy transformations jited:0 32178 32475 PASS
test_bpf: #240 BPF_MAXINSNS: Jump heavy test jited:0 10518 PASS
test_bpf: #233 BPF_MAXINSNS: Maximum possible literals jited:1 4 PASS
test_bpf: #234 BPF_MAXINSNS: Single literal jited:1 4 PASS
test_bpf: #235 BPF_MAXINSNS: Run/add until end jited:1 1625 PASS
test_bpf: #236 BPF_MAXINSNS: Too many instructions PASS
test_bpf: #237 BPF_MAXINSNS: Very long jump jited:1 8 PASS
test_bpf: #238 BPF_MAXINSNS: Ctx heavy transformations jited:1 3301 3174 PASS
test_bpf: #239 BPF_MAXINSNS: Call heavy transformations jited:1 24107 23491 PASS
test_bpf: #240 BPF_MAXINSNS: Jump heavy test jited:1 8651 PASS
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Nicolas Schichan <nschichan@freebox.fr>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now we allow storing more request socks per listener, we might
hit syncookie mode less often and hit following bug in our stack :
When we send a burst of syncookies, then exit this mode,
tcp_synq_no_recent_overflow() can return false if the ACK packets coming
from clients are coming three seconds after the end of syncookie
episode.
This is a way too strong requirement and conflicts with rest of
syncookie code which allows ACK to be aged up to 2 minutes.
Perfectly valid ACK packets are dropped just because clients might be
in a crowded wifi environment or on another planet.
So let's fix this, and also change tcp_synq_overflow() to not
dirty a cache line for every syncookie we send, as we are under attack.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Florian Westphal <fw@strlen.de>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The rx_dropped stat wasn't being reported when ip_tunnel_get_stats64 was
called. This was leading to some confusing results in my debug as I was
seeing rx_errors increment but no other value which pointed me toward the
type of error being seen.
This change corrects that by using netdev_stats_to_stats64 to copy all
available dev stats instead of just the few that were hand picked.
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Avoid two xchg calls whose return values were unused, causing a
warning on some architectures.
The relevant variable is a hint and read without mutual exclusion.
This fix makes all writers hold the receive_queue lock.
Suggested-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
None of those drivers uses last_rx for its own needs.
See 4dc89133f4 ("net: add a comment on
netdev->last_rx") for reference.
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Zhangfei Gao <zhangfei.gao@linaro.org>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: Wingman Kwok <w-kwok2@ti.com>
Cc: Murali Karicheri <m-karicheri2@ti.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Florian Fainelli says:
====================
net: phy: broken turn-around support
This is an attempt at solving the broken turn-around problem in a way that
is not specific to the mdio-gpio driver, since it affects different kinds of
platforms.
We cannot make that localized to PHY device drivers because probing the PHY
device which has a broken turn-around can fail as early as in get_phy_id(),
therefore we need a bit of help from Device Tree/platform_data.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Update mdiobb_read() to read whether the PHY has a broken turn-around,
and if it does, ignore it to make the read succeeed.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Some Ethernet PHY devices/switches may not properly release the MDIO bus
during turn-around time, and fail to drive it low, which can be seen by
some controllers as a read failure, while the data clocked in is still
correct.
Add a boolean property "broken-turn-around" which is parsed by the
generic MDIO bus probing code and will set the corresponding bit in the
MDIO bus phy_ignore_ta_mask bitmask for MDIO bus drivers to utilize that
information.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Some PHY devices/switches will not release the turn-around line as they
should do at the end of a MDIO transaction. To help with such
situations, allow MDIO bus drivers to be made aware of such
restrictions.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After commit eeb1bd5c40 ("net: Add a struct net parameter to
sock_create_kern"), we should use sock_create_kern() to create kernel
socket as the interface doesn't reference count struct net any more.
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix compile error in net/sched/cls_flower.c
net/sched/cls_flower.c: In function ‘fl_set_key’:
net/sched/cls_flower.c:240:3: error: implicit declaration of
function ‘tcf_change_indev’ [-Werror=implicit-function-declaration]
err = tcf_change_indev(net, tb[TCA_FLOWER_INDEV]);
Introduced in 77b9900ef5
Fixes: 77b9900ef5 ("tc: introduce Flower classifier")
Signed-off-by: Brian Haley <brian.haley@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Jon Maloy says:
====================
tipc: some link layer improvements
We continue eliminating redundant complexity at the link layer, and
add a couple of improvements to the packet sending functionality.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, the packet sequence number is updated and added to each
packet at the moment a packet is added to the link backlog queue.
This is wasteful, since it forces the code to traverse the send
packet list packet by packet when adding them to the backlog queue.
It would be better to just splice the whole packet list into the
backlog queue when that is the right action to do.
In this commit, we do this change. Also, since the sequence numbers
cannot now be assigned to the packets at the moment they are added
the backlog queue, we do instead calculate and add them at the moment
of transmission, when the backlog queue has to be traversed anyway.
We do this in the function tipc_link_push_packet().
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The link congestion algorithm used until now implies two problems.
- It is too generous towards lower-level messages in situations of high
load by giving "absolute" bandwidth guarantees to the different
priority levels. LOW traffic is guaranteed 10%, MEDIUM is guaranted
20%, HIGH is guaranteed 30%, and CRITICAL is guaranteed 40% of the
available bandwidth. But, in the absence of higher level traffic, the
ratio between two distinct levels becomes unreasonable. E.g. if there
is only LOW and MEDIUM traffic on a system, the former is guaranteed
1/3 of the bandwidth, and the latter 2/3. This again means that if
there is e.g. one LOW user and 10 MEDIUM users, the former will have
33.3% of the bandwidth, and the others will have to compete for the
remainder, i.e. each will end up with 6.7% of the capacity.
- Packets of type MSG_BUNDLER are created at SYSTEM importance level,
but only after the packets bundled into it have passed the congestion
test for their own respective levels. Since bundled packets don't
result in incrementing the level counter for their own importance,
only occasionally for the SYSTEM level counter, they do in practice
obtain SYSTEM level importance. Hence, the current implementation
provides a gap in the congestion algorithm that in the worst case
may lead to a link reset.
We now refine the congestion algorithm as follows:
- A message is accepted to the link backlog only if its own level
counter, and all superior level counters, permit it.
- The importance of a created bundle packet is set according to its
contents. A bundle packet created from messges at levels LOW to
CRITICAL is given importance level CRITICAL, while a bundle created
from a SYSTEM level message is given importance SYSTEM. In the latter
case only subsequent SYSTEM level messages are allowed to be bundled
into it.
This solves the first problem described above, by making the bandwidth
guarantee relative to the total number of users at all levels; only
the upper limit for each level remains absolute. In the example
described above, the single LOW user would use 1/11th of the bandwidth,
the same as each of the ten MEDIUM users, but he still has the same
guarantee against starvation as the latter ones.
The fix also solves the second problem. If the CRITICAL level is filled
up by bundle packets of that level, no lower level packets will be
accepted any more.
Suggested-by: Gergely Kiss <gergely.kiss@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
