On Fri, Mar 05, 2021 at 06:34:22PM +0100, David Hildenbrand wrote: > 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/" ? Originally, there was desire to add cma_alloc_attempts as well as cma_alloc_pages_attempts. > > I'd simply go with something like > > "total_alloc_attempts" > "failed_alloc_attempts" If we really want to remove the cma prefix, maybe, alloc_pages_attempts alloc_pages_fails If someone want to count cma_alloc itself, Then alloc_success alloc_fail Does that make sense?
