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Filename Latest commit message Latest commit date
Babu Moger 215e562251 x86/resctrl: Fix memory bandwidth counter width for AMD
commit 2c18bd525c47f882f033b0a813ecd09c93e1ecdf upstream.

Memory bandwidth is calculated reading the monitoring counter
at two intervals and calculating the delta. It is the software’s
responsibility to read the count often enough to avoid having
the count roll over _twice_ between reads.

The current code hardcodes the bandwidth monitoring counter's width
to 24 bits for AMD. This is due to default base counter width which
is 24. Currently, AMD does not implement the CPUID 0xF.[ECX=1]:EAX
to adjust the counter width. But, the AMD hardware supports much
wider bandwidth counter with the default width of 44 bits.

Kernel reads these monitoring counters every 1 second and adjusts the
counter value for overflow. With 24 bits and scale value of 64 for AMD,
it can only measure up to 1GB/s without overflowing. For the rates
above 1GB/s this will fail to measure the bandwidth.

Fix the issue setting the default width to 44 bits by adjusting the
offset.

AMD future products will implement CPUID 0xF.[ECX=1]:EAX.

 [ bp: Let the line stick out and drop {}-brackets around a single
   statement. ]

Fixes: 4d05bf71f1 ("x86/resctrl: Introduce AMD QOS feature")
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/159129975546.62538.5656031125604254041.stgit@naples-babu.amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-09 09:37:57 +02:00
arch x86/resctrl: Fix memory bandwidth counter width for AMD 2020-07-09 09:37:57 +02:00
block block: update hctx map when use multiple maps 2020-06-30 15:37:06 -04:00
certs
crypto crypto: af_alg - fix use-after-free in af_alg_accept() due to bh_lock_sock() 2020-07-09 09:37:52 +02:00
Documentation dt-bindings: display: mediatek: control dpi pins mode to avoid leakage 2020-06-22 09:30:58 +02:00
drivers irqchip/gic: Atomically update affinity 2020-07-09 09:37:56 +02:00
fs cifs: Fix the target file was deleted when rename failed. 2020-07-09 09:37:55 +02:00
include crypto: af_alg - fix use-after-free in af_alg_accept() due to bh_lock_sock() 2020-07-09 09:37:52 +02:00
init x86: Fix early boot crash on gcc-10, third try 2020-05-20 08:20:34 +02:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel kgdb: Avoid suspicious RCU usage warning 2020-07-09 09:37:51 +02:00
lib test_objagg: Fix potential memory leak in error handling 2020-06-30 15:37:04 -04:00
LICENSES
mm mm, compaction: make capture control handling safe wrt interrupts 2020-07-09 09:37:57 +02:00
net rxrpc: Fix afs large storage transmission performance drop 2020-07-09 09:37:52 +02:00
samples samples/vfs: avoid warning in statx override 2020-07-09 09:37:54 +02:00
scripts recordmcount: support >64k sections 2020-06-30 15:37:05 -04:00
security selinux: fix double free 2020-06-24 17:50:48 +02:00
sound Revert "ALSA: usb-audio: Improve frames size computation" 2020-07-09 09:37:55 +02:00
tools selftests: tpm: Use /bin/sh instead of /bin/bash 2020-07-09 09:37:51 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: arm64: Save the host's PtrAuth keys in non-preemptible context 2020-06-17 16:40:38 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: Update drm/i915 bug filing URL 2020-02-28 17:22:19 +01:00
Makefile Linux 5.4.50 2020-06-30 16:21:55 -04:00
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.