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Randall Stewart b8d60729de tcp: Congestion control cleanup.
NOTE: HEADS UP read the note below if your kernel config is not including GENERIC!!

This patch does a bit of cleanup on TCP congestion control modules. There were some rather
interesting surprises that one could get i.e. where you use a socket option to change
from one CC (say cc_cubic) to another CC (say cc_vegas) and you could in theory get
a memory failure and end up on cc_newreno. This is not what one would expect. The
new code fixes this by requiring a cc_data_sz() function so we can malloc with M_WAITOK
and pass in to the init function preallocated memory. The CC init is expected in this
case *not* to fail but if it does and a module does break the
"no fail with memory given" contract we do fall back to the CC that was in place at the time.

This also fixes up a set of common newreno utilities that can be shared amongst other
CC modules instead of the other CC modules reaching into newreno and executing
what they think is a "common and understood" function. Lets put these functions in
cc.c and that way we have a common place that is easily findable by future developers or
bug fixers. This also allows newreno to evolve and grow support for its features i.e. ABE
and HYSTART++ without having to dance through hoops for other CC modules, instead
both newreno and the other modules just call into the common functions if they desire
that behavior or roll there own if that makes more sense.

Note: This commit changes the kernel configuration!! If you are not using GENERIC in
some form you must add a CC module option (one of CC_NEWRENO, CC_VEGAS, CC_CUBIC,
CC_CDG, CC_CHD, CC_DCTCP, CC_HTCP, CC_HD). You can have more than one defined
as well if you desire. Note that if you create a kernel configuration that does not
define a congestion control module and includes INET or INET6 the kernel compile will
break. Also you need to define a default, generic adds 'options CC_DEFAULT=\"newreno\"
but you can specify any string that represents the name of the CC module (same names
that show up in the CC module list under net.inet.tcp.cc). If you fail to add the
options CC_DEFAULT in your kernel configuration the kernel build will also break.

Reviewed by: Michael Tuexen
Sponsored by: Netflix Inc.
RELNOTES:YES
Differential Revision: https://reviews.freebsd.org/D32693
2021-11-11 06:28:18 -05:00
.cirrus-ci Cirrus-CI: add some timing info on pkg install failure 2021-08-04 15:02:00 -04:00
.github [skip ci] fix syntax in CODEOWNERS 2021-07-22 10:58:54 -06:00
bin echo(1): Replace errexit() with err(3) 2021-11-09 22:12:19 +01:00
cddl zfs: merge openzfs/zfs@ec64fdb93 (master) into main 2021-10-21 15:06:06 +02:00
contrib Awk: Add error file 2021-11-06 16:24:36 -06:00
crypto ssh: enable FIDO/U2F keys 2021-11-04 13:01:44 -04:00
etc awk: Move to using two sets of tests 2021-11-05 08:53:36 -06:00
gnu libdialog: Bump shared library version to 10. 2021-10-27 09:30:24 -07:00
include Add sched_getcpu() 2021-11-10 21:18:54 +02:00
kerberos5 pkgbase: Create a FreeBSD-kerberos package 2021-09-07 10:23:14 +02:00
lib x86: provide userspace implementation of sched_getcpu() where possible 2021-11-10 21:18:54 +02:00
libexec rtld: style adjustments 2021-11-06 06:40:18 +02:00
release release: Remove unused variables in azure Makefile 2021-11-04 16:42:38 +08:00
rescue Retire synchronous PPP kernel driver sppp(4). 2021-10-22 11:41:36 -07:00
sbin ifconfig(8): Don't set network interface capabilities when there is no change. 2021-11-10 15:50:52 +01:00
secure ssh: enable FIDO/U2F keys 2021-11-04 13:01:44 -04:00
share tcp: Congestion control cleanup. 2021-11-11 06:28:18 -05:00
stand efi(8): Fix a typo in a source code comment 2021-11-07 14:07:24 +01:00
sys tcp: Congestion control cleanup. 2021-11-11 06:28:18 -05:00
targets Retire obsolete iscsi_initiator(4) 2021-10-26 16:17:35 -04:00
tests pf tests: Test PR259689 2021-11-10 11:27:22 +01:00
tools stress2: Added two test scenarios for future gunion(8) 2021-11-11 10:11:49 +01:00
usr.bin sockstat(1): Update Synopsis section 2021-11-10 15:22:06 -05:00
usr.sbin service(8): Bump date after commit 66d795ec19 . 2021-11-09 22:33:04 +01:00
.arcconfig Remove history.immutable from .arcconfig 2021-04-13 12:36:25 +01:00
.arclint arc lint: ignore /tests/ in chmod 2017-12-19 03:38:06 +00:00
.cirrus.yml Cirrus-CI: add a manually triggered arm64 task 2021-09-14 15:12:55 -04:00
.clang-format clang-format: Add bitset loop macros 2021-09-21 12:08:01 -04:00
.gitattributes Add a basic clang-format configuration file 2019-06-07 15:23:52 +00:00
.gitignore gitignore: Add .clangd and .ccls-cache 2021-06-04 16:56:08 +08:00
COPYRIGHT copyrights: Happy New Year 2021 2020-12-31 10:29:44 -05:00
LOCKS LOCKS: update current locks 2018-06-09 03:08:04 +00:00
MAINTAINERS [skip ci] volunteer to maintain POSIX AIO 2021-05-30 17:21:12 -06:00
Makefile Revert "Fix native-xtools build" 2021-08-03 10:00:28 -07:00
Makefile.inc1 Remove arm/linux from sysent toplevel target 2021-11-10 21:18:53 +02:00
Makefile.libcompat ncurses: fix libcompat (lib32 for example) building 2021-10-04 14:16:32 +02:00
Makefile.sys.inc AUTO_OBJ: For all top-level targets enforce using an OBJDIR. 2017-12-05 21:29:47 +00:00
ObsoleteFiles.inc libdialog: Bump shared library version to 10. 2021-10-27 09:30:24 -07:00
README.md Whitespace cleanup 2021-03-12 19:57:58 +08:00
RELNOTES Add notes about vt beeping 2021-11-04 09:15:38 -06:00
UPDATING tcp: Congestion control cleanup. 2021-11-11 06:28:18 -05:00

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