linux/sound/core
Takashi Iwai d4cfb30fce ALSA: pcm: Set per-card upper limit of PCM buffer allocations
Currently, the available buffer allocation size for a PCM stream
depends on the preallocated size; when a buffer has been preallocated,
the max buffer size is set to that size, so that application won't
re-allocate too much memory.  OTOH, when no preallocation is done,
each substream may allocate arbitrary size of buffers as long as
snd_pcm_hardware.buffer_bytes_max allows -- which can be quite high,
HD-audio sets 1GB there.

It means that the system may consume a high amount of pages for PCM
buffers, and they are pinned and never swapped out.  This can lead to
OOM easily.

For avoiding such a situation, this patch adds the upper limit per
card.  Each snd_pcm_lib_malloc_pages() and _free_pages() calls are
tracked and it will return an error if the total amount of buffers
goes over the defined upper limit.  The default value is set to 32MB,
which should be really large enough for usual operations.

If larger buffers are needed for any specific usage, it can be
adjusted (also dynamically) via snd_pcm.max_alloc_per_card option.
Setting zero there means no chceck is performed, and again, unlimited
amount of buffers are allowed.

Link: https://lore.kernel.org/r/20200120124423.11862-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2020-01-21 07:11:55 +01:00
..
oss ALSA: oss: More constifications 2020-01-05 16:14:58 +01:00
seq Merge branch 'for-linus' into for-next 2020-01-20 11:44:51 +01:00
compress_offload.c ALSA: core: Constify snd_device_ops definitions 2020-01-03 09:23:51 +01:00
control_compat.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
control.c ALSA: control: potential uninitialized return value 2020-01-08 07:20:28 +01:00
ctljack.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
device.c ALSA: core: Treat snd_device_ops as const 2020-01-03 09:23:50 +01:00
hrtimer.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
hwdep_compat.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
hwdep.c ALSA: core: Constify snd_device_ops definitions 2020-01-03 09:23:51 +01:00
info_oss.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
info.c ALSA: info: More constifications 2020-01-05 16:14:57 +01:00
init.c ALSA: pcm: Set per-card upper limit of PCM buffer allocations 2020-01-21 07:11:55 +01:00
isadma.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
jack.c ALSA: jack: More constification 2020-01-05 16:14:57 +01:00
Kconfig ALSA: control: Add verification for kctl accesses 2020-01-04 09:37:59 +01:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
memalloc.c ALSA: memalloc: Add vmalloc buffer allocation support 2019-11-06 15:43:33 +01:00
memory.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
misc.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
pcm_compat.c ALSA: add new 32-bit layout for snd_pcm_mmap_status/control 2019-12-13 11:25:58 +01:00
pcm_dmaengine.c ASoC: pcm_dmaengine: Extract snd_dmaengine_pcm_refine_runtime_hwparams 2019-10-01 12:18:25 +01:00
pcm_drm_eld.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
pcm_iec958.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
pcm_lib.c ALSA: pcm: More constifications 2020-01-05 16:14:29 +01:00
pcm_local.h ALSA: pcm: Make snd_pcm_hw_constraints_init() and _complete() static 2020-01-16 17:29:33 +01:00
pcm_memory.c ALSA: pcm: Set per-card upper limit of PCM buffer allocations 2020-01-21 07:11:55 +01:00
pcm_misc.c ALSA: pcm: More constifications 2020-01-05 16:14:29 +01:00
pcm_native.c ALSA: pcm: Make snd_pcm_hw_constraints_init() and _complete() static 2020-01-16 17:29:33 +01:00
pcm_param_trace.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pcm_timer.c ALSA: timer: Constify snd_timer_hardware definitions 2020-01-03 09:24:07 +01:00
pcm_trace.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pcm.c ALSA: pcm: More constifications 2020-01-05 16:14:29 +01:00
rawmidi_compat.c ALSA: Avoid using timespec for struct snd_rawmidi_status 2019-12-11 22:06:16 +01:00
rawmidi.c ALSA: rawmidi: More constification 2020-01-05 16:14:58 +01:00
seq_device.c ALSA: core: Constify snd_device_ops definitions 2020-01-03 09:23:51 +01:00
sgbuf.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
sound_oss.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
sound.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
timer_compat.c ALSA: Avoid using timespec for struct snd_timer_tread 2019-12-13 11:25:57 +01:00
timer.c ALSA: timer: fix nsec/sec initialization confusion 2020-01-12 09:08:22 +01:00
vmaster.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 372 2019-06-05 17:37:10 +02:00