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Kuniyuki Iwashima cf21b355cc af_unix: Optimise hash table layout. Commit `6dd4142fb5` ("Merge branch 'af_unix-per-netns-socket-hash'") and commit `51bae889fe` ("af_unix: Put pathname sockets in the global hash table.") changed a hash table layout. Before: unix_socket_table [0 - 255] : abstract & pathname sockets [256 - 511] : unnamed sockets After: per-netns table [0 - 255] : abstract & pathname sockets [256 - 511] : unnamed sockets bsd_socket_table [0 - 255] : pathname sockets (sk_bind_node) Now, while looking up sockets, we traverse the global table for the pathname sockets and the first half of each per-netns hash table for abstract sockets, where pathname sockets are also linked. Thus, the more pathname sockets we have, the longer we take to look up abstract sockets. This characteristic has been there before the layout change, but we can improve it now. This patch changes the per-netns hash table's layout so that sockets not requiring lookup reside in the first half and do not impact the lookup of abstract sockets. per-netns table [0 - 255] : pathname & unnamed sockets [256 - 511] : abstract sockets bsd_socket_table [0 - 255] : pathname sockets (sk_bind_node) We have run a test that bind()s 100,000 abstract/pathname sockets for each, bind()s an abstract socket 100,000 times and measures the time on __unix_find_socket_byname(). The result shows that the patch makes each lookup faster. Without this patch: $ sudo ./funclatency -p 2278 --microseconds __unix_find_socket_byname.isra.44 usec : count distribution 0 -> 1 : 0 \| \| 2 -> 3 : 0 \| \| 4 -> 7 : 0 \| \| 8 -> 15 : 126 \| \| 16 -> 31 : 1438 \|* \| 32 -> 63 : 4150 \|* \| 64 -> 127 : 9049 \|*** \| 128 -> 255 : 37704 \|*************************** \| 256 -> 511 : 47533 \|*************************************\| With this patch: $ sudo ./funclatency -p 3648 --microseconds __unix_find_socket_byname.isra.46 usec : count distribution 0 -> 1 : 109 \| \| 2 -> 3 : 318 \| \| 4 -> 7 : 725 \| \| 8 -> 15 : 2501 \| \| 16 -> 31 : 3061 \| \| 32 -> 63 : 4028 \|* \| 64 -> 127 : 9312 \|***** \| 128 -> 255 : 51372 \|************************************\| 256 -> 511 : 28574 \|******************** \| Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://lore.kernel.org/r/20220705233715.759-1-kuniyu@amazon.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>		2022-07-07 13:19:01 +02:00
arch	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2022-06-30 16:31:00 -07:00
block	block: remove WARN_ON() from bd_link_disk_holder	2022-06-23 07:48:05 -06:00
certs	Certs changes	2022-06-21 12:13:53 -05:00
crypto	Certs changes	2022-06-21 12:13:53 -05:00
Documentation	tls: rx: add sockopt for enabling optimistic decrypt with TLS 1.3	2022-07-06 12:56:35 +01:00
drivers	qed: Use bitmap_empty()	2022-07-06 19:55:14 -07:00
fs	vfs: fix copy_file_range() regression in cross-fs copies	2022-06-30 15:16:38 -07:00
include	tls: rx: add sockopt for enabling optimistic decrypt with TLS 1.3	2022-07-06 12:56:35 +01:00
init	gcc-12: disable '-Warray-bounds' universally for now	2022-06-09 10:11:12 -07:00
ipc	These changes update the ipc sysctls so that they are fundamentally	2022-06-03 15:54:57 -07:00
kernel	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2022-06-30 16:31:00 -07:00
lib	Build tool updates:	2022-06-19 09:54:16 -05:00
LICENSES	LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers	2021-12-16 14:33:10 +01:00
mm	Minor things, mainly - mailmap updates, MAINTAINERS updates, etc.	2022-06-26 14:00:55 -07:00
net	af_unix: Optimise hash table layout.	2022-07-07 13:19:01 +02:00
samples	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2022-06-23 12:33:24 -07:00
scripts	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2022-06-30 16:31:00 -07:00
security	selinux: free contexts previously transferred in selinux_add_opt()	2022-06-15 21:20:45 -04:00
sound	sound fixes for 5.19-rc4	2022-06-23 08:44:00 -05:00
tools	selftests: tls: add selftest variant for pad	2022-07-06 12:56:35 +01:00
usr	Not a lot of material this cycle. Many singleton patches against various	2022-05-27 11:22:03 -07:00
virt	KVM: x86: disable preemption around the call to kvm_arch_vcpu_{un\|}blocking	2022-06-09 10:52:20 -04:00
.clang-format	clang-format: Fix space after for_each macros	2022-05-20 19:27:16 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore	kbuild: split the second line of .mod into .usyms	2022-05-08 03:16:59 +09:00
.mailmap	mailmap: add entry for Christian Marangi	2022-06-16 19:11:32 -07:00
COPYING
CREDITS	MAINTAINERS: replace a Microchip AT91 maintainer	2022-02-09 11:30:01 +01:00
Kbuild
Kconfig
MAINTAINERS	eth: remove neterion/vxge	2022-07-05 15:26:31 -07:00
Makefile	Linux 5.19-rc4	2022-06-26 14:22:10 -07:00
README

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.