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Yuchung Cheng c4dbd9e931 UPSTREAM: tcp: up initial rmem to 128KB and SYN rwin to around 64KB
Previously TCP initial receive buffer is ~87KB by default and
the initial receive window is ~29KB (20 MSS). This patch changes
the two numbers to 128KB and ~64KB (rounding down to the multiples
of MSS) respectively. The patch also simplifies the calculations s.t.
the two numbers are directly controlled by sysctl tcp_rmem[1]:

  1) Initial receiver buffer budget (sk_rcvbuf): while this should
     be configured via sysctl tcp_rmem[1], previously tcp_fixup_rcvbuf()
     always override and set a larger size when a new connection
     establishes.

  2) Initial receive window in SYN: previously it is set to 20
     packets if MSS <= 1460. The number 20 was based on the initial
     congestion window of 10: the receiver needs twice amount to
     avoid being limited by the receive window upon out-of-order
     delivery in the first window burst. But since this only
     applies if the receiving MSS <= 1460, connection using large MTU
     (e.g. to utilize receiver zero-copy) may be limited by the
     receive window.

With this patch TCP memory configuration is more straight-forward and
more properly sized to modern high-speed networks by default. Several
popular stacks have been announcing 64KB rwin in SYNs as well.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Wei Wang <weiwan@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit a337531b94)
Signed-off-by: Chenbo Feng <fengc@google.com>

This patch is backported from 4.20 to allow us to drop "ANDROID: net:
ipv4: tcp: add a sysctl to config the tcp_default_init_rwnd"

Bug: 118591209
Test: net_test sock_diag_test.py
Change-Id: I7c38947205001912891750870d103b7268b44828
2018-12-05 09:48:11 -08:00
arch ANDROID: cuttlefish_defconfig: Enable EAS related defines 2018-12-05 09:48:10 -08:00
block block: Clear kernel memory before copying to user 2018-11-27 16:13:05 +01:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: user - fix leaking uninitialized memory to userspace 2018-11-21 09:19:24 +01:00
Documentation Merge branch eas-dev into experimental/android-4.19 2018-12-05 09:48:08 -08:00
drivers Merge branch eas-dev into experimental/android-4.19 2018-12-05 09:48:08 -08:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs ceph: quota: fix null pointer dereference in quota check 2018-11-27 16:13:05 +01:00
include Merge branch eas-dev into experimental/android-4.19 2018-12-05 09:48:08 -08:00
init ANDROID: sched: fair/tune: Add schedtune with cgroups interface 2018-10-26 11:57:46 +01:00
ipc ipc/shm.c: use ERR_CAST() for shm_lock() error return 2018-10-05 16:32:04 -07:00
kernel BACKPORT: sched/fair: Fix cpu_util_wake() for 'execl' type workloads 2018-12-05 09:48:10 -08:00
lib lib/raid6: Fix arm64 test build 2018-11-27 16:13:05 +01:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm mm/swapfile.c: use kvzalloc for swap_info_struct allocation 2018-11-21 09:19:24 +01:00
net UPSTREAM: tcp: up initial rmem to 128KB and SYN rwin to around 64KB 2018-12-05 09:48:11 -08:00
samples samples: disable CONFIG_SAMPLES for UML 2018-10-11 02:15:46 +09:00
scripts ANDROID: Kbuild, LLVMLinux: allow overriding clang target triple 2018-12-05 09:47:58 -08:00
security apparmor: Fix uninitialized value in aa_split_fqname 2018-11-27 16:13:00 +01:00
sound ALSA: hda/ca0132 - Call pci_iounmap() instead of iounmap() 2018-11-27 16:13:09 +01:00
tools perf tools: Do not zero sample_id_all for group members 2018-11-27 16:13:06 +01:00
usr initramfs: move gen_initramfs_list.sh from scripts/ to usr/ 2018-08-22 23:21:44 +09:00
virt KVM: arm64: Fix caching of host MDCR_EL2 value 2018-11-13 11:08:47 -08:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
build.config.cuttlefish.aarch64 ANDROID: defconfig / build config for cuttlefish 2018-12-05 09:47:58 -08:00
build.config.cuttlefish.x86_64 ANDROID: defconfig / build config for cuttlefish 2018-12-05 09:47:58 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS MAINTAINERS: Add an entry for the code of conduct 2018-10-22 07:33:36 +01:00
Makefile ANDROID: Kbuild, LLVMLinux: allow overriding clang target triple 2018-12-05 09:47:58 -08:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.