At Wed, 21 Sep 2011 08:26:27 -0500, Pierre-Louis Bossart wrote:

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Default of 2MB of physically-contiguous memory can be too high for embedded solutions, make the size configurable.

Hm, maybe better to have an option for global limit of preallocation? The problem is not necessarily specific to snd-aloop.

Not sure I understand the comment. This code is essentially the same as the configuration option for HDAudio, and the parameter value defines the amount of preallocated memory, with a limit to 32MB.

I meant to have a kconfig option to limit the upper-bound of pre-alloc buffer sizes for all drivers. That is, a patch like below (untested)

Takashi

--- diff --git a/sound/core/Kconfig b/sound/core/Kconfig index 475455c..525ed28 100644 --- a/sound/core/Kconfig +++ b/sound/core/Kconfig @@ -204,6 +204,15 @@ config SND_PCM_XRUN_DEBUG sound clicking when system is loaded, it may help to determine the process or driver which causes the scheduling gaps.

+config SND_PCM_MAX_PREALLOC_SIZE + int "Maximum pre-allocated buffer size" + range 0 32768 + default 0 + depends on EMBEDDED + help + Specifies the default upper-limit of PCM pre-allocation + buffer sizes in kB. Zero means unlimited. + config SND_VMASTER bool

diff --git a/sound/core/pcm_memory.c b/sound/core/pcm_memory.c index 150cb7e..a09425c 100644 --- a/sound/core/pcm_memory.c +++ b/sound/core/pcm_memory.c @@ -270,6 +270,9 @@ int snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream, int type, struct device *data, size_t size, size_t max) { + if (CONFIG_SND_PCM_MAX_PREALLOC_SIZE && + max > CONFIG_PCM_SND_MAX_PREALLOC_SIZE * 1024) + max = CONFIG_SND_PCM_PREALLOC_SIZE * 1024; substream->dma_buffer.dev.type = type; substream->dma_buffer.dev.dev = data; return snd_pcm_lib_preallocate_pages1(substream, size, max);