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Kai Vehmanen a61c7d88d3 ALSA: memalloc: use __GFP_RETRY_MAYFAIL for DMA mem allocs
Use __GFP_RETRY_MAYFAIL instead of __GFP__NORETRY in
snd_dma_dev_alloc(), snd_dma_wc_alloc() and friends, to allocate pages
for device memory. The MAYFAIL flag retains the semantics of not
triggering the OOM killer, but lowers the risk of alloc failure.

MAYFAIL flag was added in commit dcda9b0471 ("mm, tree wide: replace
__GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic").

This change addresses recurring failures with SOF audio driver in test
cases where a system suspend-resume stress test is run, combined with an
active high memory-load use-case. The failure typically shows up as:

[ 379.480229] sof-audio-pci-intel-tgl 0000:00:1f.3: booting DSP firmware
[ 379.484803] sof-audio-pci-intel-tgl 0000:00:1f.3: error: memory alloc failed: -12
[ 379.484810] sof-audio-pci-intel-tgl 0000:00:1f.3: error: dma prepare for ICCMAX stream failed

Multiple fixes to reduce the memory usage of DSP boot have been
identified in SOF driver, but even with those fixes, debug on affected
systems has shown that even a single page alloc may fail with
__GFP_NORETRY. When this occurs, system is under significant load on
physical memory, but a lot of reclaimable pages are available, so the
system has not run out of memory. With __GFP_RETRY_MAYFAIL, the errors
are not hit in these stress tests.

The alloc failure is severe as audio capability is completely lost if
alloc failure is hit at system resume.

An alternative solution was considered where the resources for DSP boot
would be kept allocated until driver is unbound. This would avoid the
allocation failure, but consume memory that is only needed temporarily
at probe and resume time. It seems better to not hang on to the memory,
but rather work a bit harder for allocating the pages at resume.

BugLink: https://github.com/thesofproject/linux/issues/3844
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20220923153501.3326041-1-kai.vehmanen@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2022-09-26 08:23:37 +02:00
Documentation Merge branch 'for-linus' into for-next 2022-09-22 13:54:20 +02:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
arch arm64 fixes for -rc5 2022-09-11 07:48:21 -04:00
block block-6.0-2022-09-09 2022-09-09 15:03:08 -04:00
certs Kbuild updates for v5.20 2022-08-10 10:40:41 -07:00
crypto crypto: blake2b: effectively disable frame size warning 2022-08-10 17:59:11 -07:00
drivers IOMMU Fixes for Linux v6.0-rc4 2022-09-11 07:32:26 -04:00
fs Driver core fixes for 6.0-rc5 2022-09-09 15:08:40 -04:00
include ALSA: hda/hdmi: Use only dynamic PCM device allocation 2022-09-22 13:58:16 +02:00
init arm64 fixes for -rc3 2022-08-26 11:32:53 -07:00
io_uring io_uring-6.0-2022-09-09 2022-09-09 14:57:18 -04:00
ipc Updates to various subsystems which I help look after. lib, ocfs2, 2022-08-07 10:03:24 -07:00
kernel dma-mapping fixes for Linux 6.0 2022-09-10 12:18:19 -04:00
lib This push fixes a boot performance regression due to an unnecessary 2022-08-31 09:47:06 -07:00
mm mm: pagewalk: Fix race between unmap and page walker 2022-09-03 10:13:13 -07:00
net sch_sfb: Also store skb len before calling child enqueue 2022-09-08 11:12:58 +02:00
samples Tracing updates for 5.20 / 6.0 2022-08-05 09:41:12 -07:00
scripts Kbuild fixes for v6.0 (2nd) 2022-09-11 15:16:47 -04:00
security Landlock fix for v6.0-rc4 2022-09-02 15:24:08 -07:00
sound ALSA: memalloc: use __GFP_RETRY_MAYFAIL for DMA mem allocs 2022-09-26 08:23:37 +02:00
tools linux-kselftest-kunit-fixes-6.0-rc5 2022-09-09 14:13:36 -04:00
usr Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
virt KVM: Drop unnecessary initialization of "ops" in kvm_ioctl_create_device() 2022-08-19 04:05:43 -04:00
.clang-format PCI/DOE: Add DOE mailbox support functions 2022-07-19 15:38:04 -07:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore kbuild: split the second line of *.mod into *.usyms 2022-05-08 03:16:59 +09:00
.mailmap .mailmap: update Luca Ceresoli's e-mail address 2022-08-28 14:02:46 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS drm for 5.20/6.0 2022-08-03 19:52:08 -07:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS v6.0 second rc pull request 2022-09-09 14:46:44 -04:00
Makefile Linux 6.0-rc5 2022-09-11 16:22:01 -04:00
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.