On 04.03.21 17:17, Minchan Kim wrote:
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 allocation attempts * 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/cma_alloc_pages_[attempts|fails] /sys/kernel/mm/cma/SENSOR/cma_alloc_pages_[attempts|fails] /sys/kernel/mm/cma/BLUETOOTH/cma_alloc_pages_[attempts|fails] The cma_stat was intentionally allocated by dynamic allocation to harmonize with kobject lifetime management. https://lore.kernel.org/linux-mm/YCOAmXqt6dZkCQYs@xxxxxxxxx/ Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx> Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx> --- From v3 - https://lore.kernel.org/linux-mm/20210303205053.2906924-1-minchan@xxxxxxxxxx/ * kmalloc_array - akpm * add why cma_stat was implemented by dynamic allocation - akpm * use !__GFP_NOWARN facility to print error - akpm From v2 - https://lore.kernel.org/linux-mm/20210208180142.2765456-1-minchan@xxxxxxxxxx/ * sysfs doc and description modification - jhubbard From v1 - https://lore.kernel.org/linux-mm/20210203155001.4121868-1-minchan@xxxxxxxxxx/ * fix sysfs build and refactoring - willy * rename and drop some attributes - jhubbard Documentation/ABI/testing/sysfs-kernel-mm-cma | 25 ++++ mm/Kconfig | 7 ++ mm/Makefile | 1 + mm/cma.c | 6 +- mm/cma.h | 18 +++ mm/cma_sysfs.c | 110 ++++++++++++++++++ 6 files changed, 166 insertions(+), 1 deletion(-) create mode 100644 Documentation/ABI/testing/sysfs-kernel-mm-cma create mode 100644 mm/cma_sysfs.c diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-cma b/Documentation/ABI/testing/sysfs-kernel-mm-cma new file mode 100644 index 000000000000..f518af819cee --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-mm-cma @@ -0,0 +1,25 @@ +What: /sys/kernel/mm/cma/ +Date: Feb 2021 +Contact: Minchan Kim <minchan@xxxxxxxxxx> +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: + + cma_alloc_pages_attempts + cma_alloc_pages_fails
Nit: why "cma_" again when we are already under "/cma/" ? I'd simply go with something like "total_alloc_attempts" "failed_alloc_attempts" But maybe this has been discussed already.
+ +What: /sys/kernel/mm/cma/<cma-heap-name>/cma_alloc_pages_attempts +Date: Feb 2021 +Contact: Minchan Kim <minchan@xxxxxxxxxx> +Description: + the number of pages CMA API tried to allocate + +What: /sys/kernel/mm/cma/<cma-heap-name>/cma_alloc_pages_fails +Date: Feb 2021 +Contact: Minchan Kim <minchan@xxxxxxxxxx> +Description: + the number of pages CMA API failed to allocate
This will be useful. -- Thanks, David / dhildenb
