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Filename Latest commit message Latest commit date
Ilya Ponetayev ea2628dd58 sch_cake: don't try to reallocate or unshare skb unconditionally
[ Upstream commit 9208d2863ac689a563b92f2161d8d1e7127d0add ]

cake_handle_diffserv() tries to linearize mac and network header parts of
skb and to make it writable unconditionally. In some cases it leads to full
skb reallocation, which reduces throughput and increases CPU load. Some
measurements of IPv4 forward + NAPT on MIPS router with 580 MHz single-core
CPU was conducted. It appears that on kernel 4.9 skb_try_make_writable()
reallocates skb, if skb was allocated in ethernet driver via so-called
'build skb' method from page cache (it was discovered by strange increase
of kmalloc-2048 slab at first).

Obtain DSCP value via read-only skb_header_pointer() call, and leave
linearization only for DSCP bleaching or ECN CE setting. And, as an
additional optimisation, skip diffserv parsing entirely if it is not needed
by the current configuration.

Fixes: c87b4ecdbe ("sch_cake: Make sure we can write the IP header before changing DSCP bits")
Signed-off-by: Ilya Ponetayev <i.ponetaev@ndmsystems.com>
[ fix a few style issues, reflow commit message ]
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-30 15:36:46 -04:00
arch kretprobe: Prevent triggering kretprobe from within kprobe_flush_task 2020-06-24 17:50:52 +02:00
block block/bio-integrity: don't free 'buf' if bio_integrity_add_page() failed 2020-06-30 15:36:43 -04:00
certs
crypto crypto: algboss - don't wait during notifier callback 2020-06-24 17:50:51 +02:00
Documentation dt-bindings: display: mediatek: control dpi pins mode to avoid leakage 2020-06-22 09:30:58 +02:00
drivers net: phy: Check harder for errors in get_phy_id() 2020-06-30 15:36:46 -04:00
fs f2fs: avoid utf8_strncasecmp() with unstable name 2020-06-24 17:50:50 +02:00
include sctp: Don't advertise IPv4 addresses if ipv6only is set on the socket 2020-06-30 15:36:45 -04:00
init x86: Fix early boot crash on gcc-10, third try 2020-05-20 08:20:34 +02:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel kretprobe: Prevent triggering kretprobe from within kprobe_flush_task 2020-06-24 17:50:52 +02:00
lib lib/zlib: remove outdated and incorrect pre-increment optimization 2020-06-24 17:50:39 +02:00
LICENSES
mm mm: call cond_resched() from deferred_init_memmap() 2020-06-22 09:31:14 +02:00
net sch_cake: don't try to reallocate or unshare skb unconditionally 2020-06-30 15:36:46 -04:00
samples samples: bpf: Fix build error 2020-06-03 08:21:15 +02:00
scripts scripts: headers_install: Exit with error on config leak 2020-06-24 17:50:33 +02:00
security selinux: fix double free 2020-06-24 17:50:48 +02:00
sound ASoC: rt5645: Add platform-data for Asus T101HA 2020-06-24 17:50:42 +02:00
tools perf stat: Fix NULL pointer dereference 2020-06-24 17:50:45 +02:00
usr
virt KVM: arm64: Save the host's PtrAuth keys in non-preemptible context 2020-06-17 16:40:38 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.49 2020-06-24 17:50:53 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.