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linux/Documentation/ABI/testing/sysfs-kernel-mm-cma

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mm: cma: support sysfs Since CMA is getting used more widely, it's more important to keep monitoring CMA statistics for system health since it's directly related to user experience. This patch introduces sysfs statistics for CMA, in order to provide some basic monitoring of the CMA allocator. * the number of CMA page successful allocations * the number of CMA page allocation failures These two values allow the user to calcuate the allocation failure rate for each CMA area. e.g.) /sys/kernel/mm/cma/WIFI/alloc_pages_[success|fail] /sys/kernel/mm/cma/SENSOR/alloc_pages_[success|fail] /sys/kernel/mm/cma/BLUETOOTH/alloc_pages_[success|fail] The cma_stat was intentionally allocated by dynamic allocation to harmonize with kobject lifetime management. https://lore.kernel.org/linux-mm/YCOAmXqt6dZkCQYs@kroah.com/ Link: https://lkml.kernel.org/r/20210324230759.2213957-1-minchan@kernel.org Link: https://lore.kernel.org/linux-mm/20210316100433.17665-1-colin.king@canonical.com/ Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Colin Ian King <colin.king@canonical.com> Tested-by: Dmitry Osipenko <digetx@gmail.com> Reviewed-by: Dmitry Osipenko <digetx@gmail.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Tested-by: Anders Roxell <anders.roxell@linaro.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: John Dias <joaodias@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Colin Ian King <colin.king@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-04 18:37:28 -07:00
What: /sys/kernel/mm/cma/
Date: Feb 2021
Contact: Minchan Kim <minchan@kernel.org>
Description:
/sys/kernel/mm/cma/ contains a subdirectory for each CMA
heap name (also sometimes called CMA areas).
Each CMA heap subdirectory (that is, each
/sys/kernel/mm/cma/<cma-heap-name> directory) contains the
following items:
alloc_pages_success
alloc_pages_fail
What: /sys/kernel/mm/cma/<cma-heap-name>/alloc_pages_success
Date: Feb 2021
Contact: Minchan Kim <minchan@kernel.org>
Description:
the number of pages CMA API succeeded to allocate
What: /sys/kernel/mm/cma/<cma-heap-name>/alloc_pages_fail
Date: Feb 2021
Contact: Minchan Kim <minchan@kernel.org>
Description:
the number of pages CMA API failed to allocate
mm/cma: add sysfs file 'release_pages_success' This adds the following new sysfs file tracking the number of successfully released pages from a given CMA heap area. This file will be available via CONFIG_CMA_SYSFS and help in determining active CMA pages available on the CMA heap area. This adds a new 'nr_pages_released' (CONFIG_CMA_SYSFS) into 'struct cma' which gets updated during cma_release(). /sys/kernel/mm/cma/<cma-heap-area>/release_pages_success After this change, an user will be able to find active CMA pages available in a given CMA heap area via the following method. Active pages = alloc_pages_success - release_pages_success That's valuable information for both software designers, and system admins as it allows them to tune the number of CMA pages available in the system. This increases user visibility for allocated CMA area and its utilization. Link: https://lkml.kernel.org/r/20240206045731.472759-1-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-02-06 10:27:31 +05:30
What: /sys/kernel/mm/cma/<cma-heap-name>/release_pages_success
Date: Feb 2024
Contact: Anshuman Khandual <anshuman.khandual@arm.com>
Description:
the number of pages CMA API succeeded to release
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