kernel_optimize_test/sound
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
..
ac97 ALSA: ac97: Constify snd_ac97_bus_ops definitions 2020-01-03 09:24:11 +01:00
aoa ALSA: aoa: More constifications 2020-01-05 16:14:27 +01:00
arm ALSA: arm: More constification 2020-01-05 16:15:07 +01:00
atmel ALSA: atmel: Constify snd_ac97_bus_ops definitions 2020-01-03 09:24:12 +01:00
core ALSA: pcm: Set per-card upper limit of PCM buffer allocations 2020-01-21 07:11:55 +01:00
drivers ALSA: serial-u16550: More constification 2020-01-05 16:15:08 +01:00
firewire Merge branch 'for-linus' into for-next 2020-01-20 11:44:51 +01:00
hda ALSA: hda: Update kernel-doc function parameter descriptions 2020-01-14 07:40:37 +01:00
i2c ALSA: i2c: Constify snd_kcontrol_new items 2020-01-03 09:24:24 +01:00
isa ALSA: sc6000: More constification 2020-01-05 16:15:05 +01:00
mips ALSA: mips: Constify snd_device_ops definitions 2020-01-03 09:24:02 +01:00
oss
parisc ALSA: parisc: Constify snd_kcontrol_new items 2020-01-03 09:24:35 +01:00
pci Merge branch 'for-linus' into for-next 2020-01-20 11:44:51 +01:00
pcmcia ALSA: pdaudiocf: More constification 2020-01-05 16:15:13 +01:00
ppc ALSA: ppc: More constifications 2020-01-05 16:14:43 +01:00
sh ALSA: sh: Fix compile warning wrt const 2020-01-05 16:15:14 +01:00
soc Merge branch 'for-linus' into for-next 2020-01-20 11:44:51 +01:00
sparc ALSA: sparc: More constifications 2020-01-05 16:14:56 +01:00
spi ALSA: spi: More constification 2020-01-05 16:15:13 +01:00
synth ALSA: emux: More constifications 2020-01-05 16:14:46 +01:00
usb Merge branch 'for-linus' into for-next 2020-01-20 11:44:51 +01:00
x86 ALSA: x86: Drop superfluous ioctl PCM ops 2019-12-11 07:25:34 +01:00
xen ALSA: xen: Drop superfluous ioctl PCM ops 2019-12-11 07:25:35 +01:00
ac97_bus.c ALSA: ac97: Treat snd_ac97_bus_ops as const 2020-01-03 09:24:08 +01:00
Kconfig
last.c
Makefile
sound_core.c