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Filename Latest commit message Latest commit date
Valentin Schneider 407ec382ba sched/topology: Make sched_init_numa() use a set for the deduplicating sort
commit 620a6dc40754dc218f5b6389b5d335e9a107fd29 upstream.

The deduplicating sort in sched_init_numa() assumes that the first line in
the distance table contains all unique values in the entire table. I've
been trying to pen what this exactly means for the topology, but it's not
straightforward. For instance, topology.c uses this example:

  node   0   1   2   3
    0:  10  20  20  30
    1:  20  10  20  20
    2:  20  20  10  20
    3:  30  20  20  10

  0 ----- 1
  |     / |
  |   /   |
  | /     |
  2 ----- 3

Which works out just fine. However, if we swap nodes 0 and 1:

  1 ----- 0
  |     / |
  |   /   |
  | /     |
  2 ----- 3

we get this distance table:

  node   0  1  2  3
    0:  10 20 20 20
    1:  20 10 20 30
    2:  20 20 10 20
    3:  20 30 20 10

Which breaks the deduplicating sort (non-representative first line). In
this case this would just be a renumbering exercise, but it so happens that
we can have a deduplicating sort that goes through the whole table in O(n²)
at the extra cost of a temporary memory allocation (i.e. any form of set).

The ACPI spec (SLIT) mentions distances are encoded on 8 bits. Following
this, implement the set as a 256-bits bitmap. Should this not be
satisfactory (i.e. we want to support 32-bit values), then we'll have to go
for some other sparse set implementation.

This has the added benefit of letting us allocate just the right amount of
memory for sched_domains_numa_distance[], rather than an arbitrary
(nr_node_ids + 1).

Note: DT binding equivalent (distance-map) decodes distances as 32-bit
values.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210122123943.1217-2-valentin.schneider@arm.com
Signed-off-by: dann frazier <dann.frazier@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-08 19:07:48 +01:00
arch x86/fpu: Correct pkru/xstate inconsistency 2022-03-02 11:41:03 +01:00
block block: Fix fsync always failed if once failed 2022-03-08 19:07:47 +01:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:47:29 +02:00
crypto crypto: pcrypt - Delay write to padata->info 2021-11-17 09:48:40 +01:00
Documentation bpf: Add kconfig knob for disabling unpriv bpf by default 2022-02-16 12:52:49 +01:00
drivers xen/netfront: destroy queues before real_num_tx_queues is zeroed 2022-03-08 19:07:47 +01:00
fs cifs: fix double free race when mount fails in cifs_get_root() 2022-03-08 19:07:45 +01:00
include sched/topology: Make sched_init_numa() use a set for the deduplicating sort 2022-03-08 19:07:48 +01:00
init bpf: Add kconfig knob for disabling unpriv bpf by default 2022-02-16 12:52:49 +01:00
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-12-01 09:23:35 +01:00
kernel sched/topology: Make sched_init_numa() use a set for the deduplicating sort 2022-03-08 19:07:48 +01:00
lib lib/iov_iter: initialize "flags" in new pipe_buffer 2022-02-23 11:59:59 +01:00
LICENSES
mm memblock: use kfree() to release kmalloced memblock regions 2022-03-02 11:41:18 +01:00
net net/smc: fix unexpected SMC_CLC_DECL_ERR_REGRMB error cause by server 2022-03-08 19:07:47 +01:00
samples samples/kretprobes: Fix return value if register_kretprobe() failed 2021-11-17 09:48:39 +01:00
scripts kconfig: fix failing to generate auto.conf 2022-02-23 12:00:01 +01:00
security ima: Do not print policy rule with inactive LSM labels 2022-02-16 12:52:47 +01:00
sound ASoC: ops: Shift tested values in snd_soc_put_volsw() by +min 2022-03-08 19:07:46 +01:00
tools perf data: Fix double free in perf_session__delete() 2022-03-02 11:41:05 +01:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: do not shrink halt_poll_ns below grow_start 2021-10-09 14:39:50 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.182 2022-03-02 11:41:18 +01:00
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.