This adds the following new sysfs file tracking the number of successfully released pages from a given CMA heap area. Also like before - this will be available via CONFIG_CMA_SYSFS, and help in determining active CMA pages available on the system. /sys/kernel/mm/cma/<cma-heap-area>/release_pages_success It adds an element 'nr_pages_released' (with CONFIG_CMA_SYSFS config) into 'struct cma' which gets updated during cma_release(). Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: linux-mm@xxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> --- This patch applies on v6.8-rc3 Some earlier relevant discussions regarding arm64 MTE dynamic tag storage in this regard can be found here. https://lore.kernel.org/all/ZbpKyNVHfhf1-AAv@raptor/ Documentation/ABI/testing/sysfs-kernel-mm-cma | 6 ++++++ mm/cma.c | 1 + mm/cma.h | 5 +++++ mm/cma_sysfs.c | 15 +++++++++++++++ 4 files changed, 27 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-cma b/Documentation/ABI/testing/sysfs-kernel-mm-cma index 02b2bb60c296..dfd755201142 100644 --- a/Documentation/ABI/testing/sysfs-kernel-mm-cma +++ b/Documentation/ABI/testing/sysfs-kernel-mm-cma @@ -23,3 +23,9 @@ Date: Feb 2021 Contact: Minchan Kim <minchan@xxxxxxxxxx> Description: the number of pages CMA API failed to allocate + +What: /sys/kernel/mm/cma/<cma-heap-name>/release_pages_success +Date: Feb 2024 +Contact: Anshuman Khandual <anshuman.khandual@xxxxxxx> +Description: + the number of pages CMA API succeeded to release diff --git a/mm/cma.c b/mm/cma.c index 2627f4ba481f..4f95266eba1d 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -559,6 +559,7 @@ bool cma_release(struct cma *cma, const struct page *pages, free_contig_range(pfn, count); cma_clear_bitmap(cma, pfn, count); + cma_sysfs_account_release_pages(cma, count); trace_cma_release(cma->name, pfn, pages, count); return true; diff --git a/mm/cma.h b/mm/cma.h index 88a0595670b7..ad61cc6dd439 100644 --- a/mm/cma.h +++ b/mm/cma.h @@ -27,6 +27,8 @@ struct cma { atomic64_t nr_pages_succeeded; /* the number of CMA page allocation failures */ atomic64_t nr_pages_failed; + /* the number of CMA page released */ + atomic64_t nr_pages_released; /* kobject requires dynamic object */ struct cma_kobject *cma_kobj; #endif @@ -44,10 +46,13 @@ static inline unsigned long cma_bitmap_maxno(struct cma *cma) #ifdef CONFIG_CMA_SYSFS void cma_sysfs_account_success_pages(struct cma *cma, unsigned long nr_pages); void cma_sysfs_account_fail_pages(struct cma *cma, unsigned long nr_pages); +void cma_sysfs_account_release_pages(struct cma *cma, unsigned long nr_pages); #else static inline void cma_sysfs_account_success_pages(struct cma *cma, unsigned long nr_pages) {}; static inline void cma_sysfs_account_fail_pages(struct cma *cma, unsigned long nr_pages) {}; +static inline void cma_sysfs_account_release_pages(struct cma *cma, + unsigned long nr_pages) {}; #endif #endif diff --git a/mm/cma_sysfs.c b/mm/cma_sysfs.c index 56347d15b7e8..f50db3973171 100644 --- a/mm/cma_sysfs.c +++ b/mm/cma_sysfs.c @@ -24,6 +24,11 @@ void cma_sysfs_account_fail_pages(struct cma *cma, unsigned long nr_pages) atomic64_add(nr_pages, &cma->nr_pages_failed); } +void cma_sysfs_account_release_pages(struct cma *cma, unsigned long nr_pages) +{ + atomic64_add(nr_pages, &cma->nr_pages_released); +} + static inline struct cma *cma_from_kobj(struct kobject *kobj) { return container_of(kobj, struct cma_kobject, kobj)->cma; @@ -48,6 +53,15 @@ static ssize_t alloc_pages_fail_show(struct kobject *kobj, } CMA_ATTR_RO(alloc_pages_fail); +static ssize_t release_pages_success_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + struct cma *cma = cma_from_kobj(kobj); + + return sysfs_emit(buf, "%llu\n", atomic64_read(&cma->nr_pages_released)); +} +CMA_ATTR_RO(release_pages_success); + static void cma_kobj_release(struct kobject *kobj) { struct cma *cma = cma_from_kobj(kobj); @@ -60,6 +74,7 @@ static void cma_kobj_release(struct kobject *kobj) static struct attribute *cma_attrs[] = { &alloc_pages_success_attr.attr, &alloc_pages_fail_attr.attr, + &release_pages_success_attr.attr, NULL, }; ATTRIBUTE_GROUPS(cma); -- 2.25.1
