AuxXxilium/linux_dsm_epyc7002
1
0
Fork 0
mirror of https://github.com/AuxXxilium/linux_dsm_epyc7002.git synced 2025-01-15 11:46:52 +07:00
Code Issues Actions Packages Projects Releases Wiki Activity
841,218 Commits 1 Branch 0 Tags 2 GiB
C 97.7%
Assembly 1.2%
Shell 0.3%
Makefile 0.3%
Python 0.2%
Other 0.1%
0b9ccc0a9b
Go to file
Peter Zijlstra 0b9ccc0a9b x86/percpu: Differentiate this_cpu_{}() and __this_cpu_{}() 
Nadav Amit reported that commit:

  b59167ac7b ("x86/percpu: Fix this_cpu_read()")

added a bunch of constraints to all sorts of code; and while some of
that was correct and desired, some of that seems superfluous.

The thing is, the this_cpu_*() operations are defined IRQ-safe, this
means the values are subject to change from IRQs, and thus must be
reloaded.

Also, the generic form:

  local_irq_save()
  __this_cpu_read()
  local_irq_restore()

would not allow the re-use of previous values; if by nothing else,
then the barrier()s implied by local_irq_*().

Which raises the point that percpu_from_op() and the others also need
that volatile.

OTOH __this_cpu_*() operations are not IRQ-safe and assume external
preempt/IRQ disabling and could thus be allowed more room for
optimization.

This makes the this_cpu_*() vs __this_cpu_*() behaviour more
consistent with other architectures.

  $ ./compare.sh defconfig-build defconfig-build1 vmlinux.o
  x86_pmu_cancel_txn                                         80         71   -9,+0
  __text_poke                                               919        964   +45,+0
  do_user_addr_fault                                       1082       1058   -24,+0
  __do_page_fault                                          1194       1178   -16,+0
  do_exit                                                  2995       3027   -43,+75
  process_one_work                                         1008        989   -67,+48
  finish_task_switch                                        524        505   -19,+0
  __schedule_bug                                            103         98   -59,+54
  __schedule_bug                                            103         98   -59,+54
  __sched_setscheduler                                     2015       2030   +15,+0
  freeze_processes                                          203        230   +31,-4
  rcu_gp_kthread_wake                                       106         99   -7,+0
  rcu_core                                                 1841       1834   -7,+0
  call_timer_fn                                             298        286   -12,+0
  can_stop_idle_tick                                        146        139   -31,+24
  perf_pending_event                                        253        239   -14,+0
  shmem_alloc_page                                          209        213   +4,+0
  __alloc_pages_slowpath                                   3284       3269   -15,+0
  umount_tree                                               671        694   +23,+0
  advance_transaction                                       803        798   -5,+0
  con_put_char                                               71         51   -20,+0
  xhci_urb_enqueue                                         1302       1295   -7,+0
  xhci_urb_enqueue                                         1302       1295   -7,+0
  tcp_sacktag_write_queue                                  2130       2075   -55,+0
  tcp_try_undo_loss                                         229        208   -21,+0
  tcp_v4_inbound_md5_hash                                   438        411   -31,+4
  tcp_v4_inbound_md5_hash                                   438        411   -31,+4
  tcp_v6_inbound_md5_hash                                   469        411   -33,-25
  tcp_v6_inbound_md5_hash                                   469        411   -33,-25
  restricted_pointer                                        434        420   -14,+0
  irq_exit                                                  162        154   -8,+0
  get_perf_callchain                                        638        624   -14,+0
  rt_mutex_trylock                                          169        156   -13,+0
  avc_has_extended_perms                                   1092       1089   -3,+0
  avc_has_perm_noaudit                                      309        306   -3,+0
  __perf_sw_event                                           138        122   -16,+0
  perf_swevent_get_recursion_context                        116        102   -14,+0
  __local_bh_enable_ip                                       93         72   -21,+0
  xfrm_input                                               4175       4161   -14,+0
  avc_has_perm                                              446        443   -3,+0
  vm_events_fold_cpu                                         57         56   -1,+0
  vfree                                                      68         61   -7,+0
  freeze_processes                                          203        230   +31,-4
  _local_bh_enable                                           44         30   -14,+0
  ip_do_fragment                                           1982       1944   -38,+0
  do_exit                                                  2995       3027   -43,+75
  __do_softirq                                              742        724   -18,+0
  cpu_init                                                 1510       1489   -21,+0
  account_system_time                                        80         79   -1,+0
                                               total   12985281   12984819   -742,+280

Reported-by: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20181206112433.GB13675@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-06-17 12:43:40 +02:00
arch x86/percpu: Differentiate this_cpu_{}() and __this_cpu_{}() 2019-06-17 12:43:40 +02:00
block blk-mq: remove WARN_ON(!q->elevator) from blk_mq_sched_free_requests 2019-06-13 03:05:58 -06:00
certs treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
crypto SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
Documentation x86/atomic: Fix smp_mb__{before,after}_atomic() 2019-06-17 12:09:59 +02:00
drivers locking/lockdep: Rename lockdep_assert_held_exclusive() -> lockdep_assert_held_write() 2019-06-17 12:09:24 +02:00
fs locking/lockdep: Rename lockdep_assert_held_exclusive() -> lockdep_assert_held_write() 2019-06-17 12:09:24 +02:00
include locking/rwsem: Make rwsem->owner an atomic_long_t 2019-06-17 12:28:06 +02:00
init Linux 5.2-rc5 2019-06-17 12:06:34 +02:00
ipc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
kernel locking/rwsem: Guard against making count negative 2019-06-17 12:28:11 +02:00
lib locking/rwsem: Make owner available even if !CONFIG_RWSEM_SPIN_ON_OWNER 2019-06-17 12:27:54 +02:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-06-16 07:28:14 -10:00
net SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
samples SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
scripts scripts/decode_stacktrace.sh: prefix addr2line with $CROSS_COMPILE 2019-06-13 17:34:56 -10:00
security locking/lockdep: Rename lockdep_assert_held_exclusive() -> lockdep_assert_held_write() 2019-06-17 12:09:24 +02:00
sound sound fixes for 5.2-rc5 2019-06-14 05:37:06 -10:00
tools mm/devm_memremap_pages: fix final page put race 2019-06-13 17:34:56 -10:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
.clang-format Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-04-17 11:26:25 -07:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore .gitignore: exclude .get_maintainer.ignore and .gitattributes 2019-05-18 11:49:54 +09:00
.mailmap A reasonably busy cycle for docs, including: 2019-05-08 12:42:50 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Farewell Martin Schwidefsky 2019-05-31 10:14:11 +02:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2019-06-08 12:48:49 -07:00
Makefile Linux 5.2-rc5 2019-06-16 08:49:45 -10:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.