d4cfb30fce
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> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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.