linux.git/arch/x86/kernel/itmt.c, branch v6.8

arch/x86: Remove now superfluous sentinel elem from ctl_table arrays

2023-10-10T22:22:02+00:00

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

Remove sentinel element from sld_sysctl and itmt_kern_table. This
removal is safe because register_sysctl_init and register_sysctl
implicitly use the array size in addition to checking for the sentinel.

Reviewed-by: Ingo Molnar 
Acked-by: Dave Hansen  # for x86
Signed-off-by: Joel Granados 
Signed-off-by: Luis Chamberlain

x86/sched/itmt: Give all SMT siblings of a core the same priority

2023-05-08T08:58:38+00:00

X86 does not have the SD_ASYM_PACKING flag in the SMT domain. The scheduler
knows how to handle SMT and non-SMT cores of different priority. There is
no reason for SMT siblings of a core to have different priorities.

Signed-off-by: Ricardo Neri 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Len Brown 
Tested-by: Zhang Rui 
Link: https://lore.kernel.org/r/20230406203148.19182-12-ricardo.neri-calderon@linux.intel.com

x86: Simplify one-level sysctl registration for itmt_kern_table

2023-03-22T18:47:21+00:00

There is no need to declare an extra tables to just create directory,
this can be easily be done with a prefix path with register_sysctl().

Simplify this registration.

Signed-off-by: Luis Chamberlain 
Signed-off-by: Dave Hansen 
Link: https://lore.kernel.org/all/20230310233248.3965389-3-mcgrof%40kernel.org

x86/sched: Decrease further the priorities of SMT siblings

2021-10-05T13:51:59+00:00

When scheduling, it is better to prefer a separate physical core rather
than the SMT sibling of a high priority core. The existing formula to
compute priorities takes such fact in consideration. There may exist,
however, combinations of priorities (i.e., maximum frequencies) in which
the priority of high-numbered SMT siblings of high-priority cores collides
with the priority of low-numbered SMT siblings of low-priority cores.

Consider for instance an SMT2 system with CPUs [0, 1] with priority 60 and
[2, 3] with priority 30(CPUs in brackets are SMT siblings. In such a case,
the resulting priorities would be [120, 60], [60, 30]. Thus, to ensure
that CPU2 has higher priority than CPU1, divide the raw priority by the
squared SMT iterator. The resulting priorities are [120, 30]. [60, 15].

Originally-by: Len Brown 
Signed-off-by: Len Brown 
Signed-off-by: Ricardo Neri 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/20210911011819.12184-2-ricardo.neri-calderon@linux.intel.com

sysctl: pass kernel pointers to ->proc_handler

2020-04-27T06:07:40+00:00

Instead of having all the sysctl handlers deal with user pointers, which
is rather hairy in terms of the BPF interaction, copy the input to and
from  userspace in common code.  This also means that the strings are
always NUL-terminated by the common code, making the API a little bit
safer.

As most handler just pass through the data to one of the common handlers
a lot of the changes are mechnical.

Signed-off-by: Christoph Hellwig 
Acked-by: Andrey Ignatov 
Signed-off-by: Al Viro

proc/sysctl: add shared variables for range check

2019-07-19T00:08:07+00:00

In the sysctl code the proc_dointvec_minmax() function is often used to
validate the user supplied value between an allowed range.  This
function uses the extra1 and extra2 members from struct ctl_table as
minimum and maximum allowed value.

On sysctl handler declaration, in every source file there are some
readonly variables containing just an integer which address is assigned
to the extra1 and extra2 members, so the sysctl range is enforced.

The special values 0, 1 and INT_MAX are very often used as range
boundary, leading duplication of variables like zero=0, one=1,
int_max=INT_MAX in different source files:

    $ git grep -E '\.extra[12].*&(zero|one|int_max)' |wc -l
    248

Add a const int array containing the most commonly used values, some
macros to refer more easily to the correct array member, and use them
instead of creating a local one for every object file.

This is the bloat-o-meter output comparing the old and new binary
compiled with the default Fedora config:

    # scripts/bloat-o-meter -d vmlinux.o.old vmlinux.o
    add/remove: 2/2 grow/shrink: 0/2 up/down: 24/-188 (-164)
    Data                                         old     new   delta
    sysctl_vals                                    -      12     +12
    __kstrtab_sysctl_vals                          -      12     +12
    max                                           14      10      -4
    int_max                                       16       -     -16
    one                                           68       -     -68
    zero                                         128      28    -100
    Total: Before=20583249, After=20583085, chg -0.00%

[mcroce@redhat.com: tipc: remove two unused variables]
  Link: http://lkml.kernel.org/r/20190530091952.4108-1-mcroce@redhat.com
[akpm@linux-foundation.org: fix net/ipv6/sysctl_net_ipv6.c]
[arnd@arndb.de: proc/sysctl: make firmware loader table conditional]
  Link: http://lkml.kernel.org/r/20190617130014.1713870-1-arnd@arndb.de
[akpm@linux-foundation.org: fix fs/eventpoll.c]
Link: http://lkml.kernel.org/r/20190430180111.10688-1-mcroce@redhat.com
Signed-off-by: Matteo Croce 
Signed-off-by: Arnd Bergmann 
Acked-by: Kees Cook 
Reviewed-by: Aaron Tomlin 
Cc: Matthew Wilcox 
Cc: Stephen Rothwell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441

2019-06-05T15:37:17+00:00

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation version 2 of the license

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 315 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Reviewed-by: Armijn Hemel 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.de
Signed-off-by: Greg Kroah-Hartman

x86/headers: Remove duplicate #includes

2017-12-12T10:32:24+00:00

These duplicate includes have been found with scripts/checkincludes.pl but
they have been removed manually to avoid removing false positives.

Signed-off-by: Pravin Shedge 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: ard.biesheuvel@linaro.org
Cc: boris.ostrovsky@oracle.com
Cc: geert@linux-m68k.org
Cc: jgross@suse.com
Cc: linux-efi@vger.kernel.org
Cc: luto@kernel.org
Cc: matt@codeblueprint.co.uk
Cc: thomas.lendacky@amd.com
Cc: tim.c.chen@linux.intel.com
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1513024951-9221-1-git-send-email-pravin.shedge4linux@gmail.com
Signed-off-by: Ingo Molnar

sched/x86: Remove unnecessary TBM3 check to update topology

2017-01-19T07:42:37+00:00

Scheduling to the max performance core is enabled by
default for Turbo Boost Maxt Technology 3.0 capable platforms.

Remove the useless sysctl_sched_itmt_enabled check to
update sched topology for adding the prioritized core scheduling
flag.

Signed-off-by: Tim Chen 
Cc: Peter Zijlstra 
Cc: Mike Galbraith 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Srinivas Pandruvada 
Cc: Thomas Gleixner 
Cc: bp@suse.de
Cc: jolsa@redhat.com
Cc: linux-acpi@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: rjw@rjwysocki.net
Link: http://lkml.kernel.org/r/1484778629-4404-1-git-send-email-tim.c.chen@linux.intel.com
Signed-off-by: Ingo Molnar

x86/sched: Use #include instead of #include

2016-11-28T08:43:49+00:00

asm/mutex.h is gone from the locking tree, which makes sched/core break the build.

Use linux/mutex.h instead, which is the canonical method.

Cc: Srinivas Pandruvada 
Cc: Rafael J. Wysocki 
Cc: Tim Chen 
Cc: peterz@infradead.org
Cc: jolsa@redhat.com
Cc: rjw@rjwysocki.net
Cc: bp@suse.de
Cc: Thomas Gleixner 
Signed-off-by: Ingo Molnar