19.03.2021 19:30, Minchan Kim пишет: > On Fri, Mar 19, 2021 at 07:24:05PM +0300, Dmitry Osipenko wrote: >> 19.03.2021 18:50, Greg Kroah-Hartman пишет: >>>> Then initialization order won't be a problem. >>> I don't understand the problem here, what is wrong with the patch as-is? >> >> The cma->stat is NULL at the time when CMA is used on ARM because >> cma->stat is initialized at the subsys level. This is the problem, >> apparently. > > That's true. > >> >>> Also, watch out, if you only make the kobject dynamic, how are you going >>> to get backwards from the kobject to the values you want to send to >>> userspace in the show functions? >> >> Still there should be a wrapper around the kobj with a back reference to >> the cma entry. If you're suggesting that I should write a patch, then I >> may take a look at it later on. Although, I assume that Minchan could >> just correct this patch and re-push it to -next. > > This is ateempt to address it. Unless any objection, let me send it to > akpm. > > From 29a9fb4f300b754ebf55e6182ba84127658ef504 Mon Sep 17 00:00:00 2001 > From: Minchan Kim <minchan@xxxxxxxxxx> > Date: Fri, 22 Jan 2021 12:31:56 -0800 > Subject: [PATCH] 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@xxxxxxxxx/ > > Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx> > --- > Documentation/ABI/testing/sysfs-kernel-mm-cma | 25 ++++ > mm/Kconfig | 7 ++ > mm/Makefile | 1 + > mm/cma.c | 7 +- > mm/cma.h | 20 ++++ > mm/cma_sysfs.c | 107 ++++++++++++++++++ > 6 files changed, 165 insertions(+), 2 deletions(-) > 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..02b2bb60c296 > --- /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: > + > + alloc_pages_success > + alloc_pages_fail > + > +What: /sys/kernel/mm/cma/<cma-heap-name>/alloc_pages_success > +Date: Feb 2021 > +Contact: Minchan Kim <minchan@xxxxxxxxxx> > +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@xxxxxxxxxx> > +Description: > + the number of pages CMA API failed to allocate > diff --git a/mm/Kconfig b/mm/Kconfig > index 24c045b24b95..febb7e8e24de 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -513,6 +513,13 @@ config CMA_DEBUGFS > help > Turns on the DebugFS interface for CMA. > > +config CMA_SYSFS > + bool "CMA information through sysfs interface" > + depends on CMA && SYSFS > + help > + This option exposes some sysfs attributes to get information > + from CMA. > + > config CMA_AREAS > int "Maximum count of the CMA areas" > depends on CMA > diff --git a/mm/Makefile b/mm/Makefile > index 72227b24a616..56968b23ed7a 100644 > --- a/mm/Makefile > +++ b/mm/Makefile > @@ -109,6 +109,7 @@ obj-$(CONFIG_CMA) += cma.o > obj-$(CONFIG_MEMORY_BALLOON) += balloon_compaction.o > obj-$(CONFIG_PAGE_EXTENSION) += page_ext.o > obj-$(CONFIG_CMA_DEBUGFS) += cma_debug.o > +obj-$(CONFIG_CMA_SYSFS) += cma_sysfs.o > obj-$(CONFIG_USERFAULTFD) += userfaultfd.o > obj-$(CONFIG_IDLE_PAGE_TRACKING) += page_idle.o > obj-$(CONFIG_DEBUG_PAGE_REF) += debug_page_ref.o > diff --git a/mm/cma.c b/mm/cma.c > index 908f04775686..ac050359faae 100644 > --- a/mm/cma.c > +++ b/mm/cma.c > @@ -507,10 +507,13 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, > > pr_debug("%s(): returned %p\n", __func__, page); > out: > - if (page) > + if (page) { > count_vm_event(CMA_ALLOC_SUCCESS); > - else > + cma_sysfs_alloc_pages_count(cma, count); > + } else { > count_vm_event(CMA_ALLOC_FAIL); > + cma_sysfs_fail_pages_count(cma, count); > + } > > return page; > } > diff --git a/mm/cma.h b/mm/cma.h > index 42ae082cb067..70fd7633fe01 100644 > --- a/mm/cma.h > +++ b/mm/cma.h > @@ -3,6 +3,12 @@ > #define __MM_CMA_H__ > > #include <linux/debugfs.h> > +#include <linux/kobject.h> > + > +struct cma_kobject { > + struct cma *cma; > + struct kobject kobj; > +}; > > struct cma { > unsigned long base_pfn; > @@ -16,6 +22,13 @@ struct cma { > struct debugfs_u32_array dfs_bitmap; > #endif > char name[CMA_MAX_NAME]; > +#ifdef CONFIG_CMA_SYSFS > + /* the number of CMA page successful allocations */ > + atomic64_t nr_pages_succeeded; > + /* the number of CMA page allocation failures */ > + atomic64_t nr_pages_failed; > + struct cma_kobject *kobj; > +#endif > }; > > extern struct cma cma_areas[MAX_CMA_AREAS]; > @@ -26,4 +39,11 @@ static inline unsigned long cma_bitmap_maxno(struct cma *cma) > return cma->count >> cma->order_per_bit; > } > > +#ifdef CONFIG_CMA_SYSFS > +void cma_sysfs_alloc_pages_count(struct cma *cma, size_t count); > +void cma_sysfs_fail_pages_count(struct cma *cma, size_t count); > +#else > +static inline void cma_sysfs_alloc_pages_count(struct cma *cma, size_t count) {}; > +static inline void cma_sysfs_fail_pages_count(struct cma *cma, size_t count) {}; > +#endif > #endif > diff --git a/mm/cma_sysfs.c b/mm/cma_sysfs.c > new file mode 100644 > index 000000000000..ca093e9e9f64 > --- /dev/null > +++ b/mm/cma_sysfs.c > @@ -0,0 +1,107 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * CMA SysFS Interface > + * > + * Copyright (c) 2021 Minchan Kim <minchan@xxxxxxxxxx> > + */ > + > +#include <linux/cma.h> > +#include <linux/kernel.h> > +#include <linux/slab.h> > + > +#include "cma.h" > + > +void cma_sysfs_alloc_pages_count(struct cma *cma, size_t count) > +{ > + atomic64_add(count, &cma->nr_pages_succeeded); > +} > + > +void cma_sysfs_fail_pages_count(struct cma *cma, size_t count) > +{ > + atomic64_add(count, &cma->nr_pages_failed); > +} > + > +#define CMA_ATTR_RO(_name) \ > + static struct kobj_attribute _name##_attr = __ATTR_RO(_name) > + > +static ssize_t alloc_pages_success_show(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) The indentations are still wrong. CHECK: Alignment should match open parenthesis #321: FILE: mm/cma_sysfs.c:28: +static ssize_t alloc_pages_success_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) > +{ > + struct cma_kobject *cma_kobj = container_of(kobj, struct cma_kobject, kobj); > + struct cma *cma = cma_kobj->cma; > + > + return sysfs_emit(buf, "%llu\n", atomic64_read(&cma->nr_pages_succeeded)); > +} > +CMA_ATTR_RO(alloc_pages_success); > + > +static ssize_t alloc_pages_fail_show(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) CHECK: Alignment should match open parenthesis #331: FILE: mm/cma_sysfs.c:38: +static ssize_t alloc_pages_fail_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) > +{ > + struct cma_kobject *cma_kobj = container_of(kobj, struct cma_kobject, kobj); > + struct cma *cma = cma_kobj->cma; > + > + return sysfs_emit(buf, "%llu\n", atomic64_read(&cma->nr_pages_failed)); > +} > +CMA_ATTR_RO(alloc_pages_fail); > + > +static void cma_kobj_release(struct kobject *kobj) > +{ > + struct cma_kobject *cma_kobj = container_of(kobj, struct cma_kobject, kobj); > + > + kfree(cma_kobj); > +} > + > +static struct attribute *cma_attrs[] = { > + &alloc_pages_success_attr.attr, > + &alloc_pages_fail_attr.attr, > + NULL, > +}; > +ATTRIBUTE_GROUPS(cma); > + > +static struct cma_kobject *cma_kobjs; > +static struct kobject *cma_kobj_root; > + > +static struct kobj_type cma_ktype = { > + .release = cma_kobj_release, > + .sysfs_ops = &kobj_sysfs_ops, > + .default_groups = cma_groups > +}; > + > +static int __init cma_sysfs_init(void) > +{ > + int i = 0; > + struct cma *cma; > + > + cma_kobj_root = kobject_create_and_add("cma", mm_kobj); > + if (!cma_kobj_root) > + return -ENOMEM; > + > + cma_kobjs = kcalloc(cma_area_count, sizeof(struct cma_kobject), > + GFP_KERNEL); CHECK: Alignment should match open parenthesis #373: FILE: mm/cma_sysfs.c:80: + cma_kobjs = kcalloc(cma_area_count, sizeof(struct cma_kobject), + GFP_KERNEL); > + if (ZERO_OR_NULL_PTR(cma_kobjs)) > + goto out; > + > + do { > + cma = &cma_areas[i]; > + cma->kobj = &cma_kobjs[i]; Does cma really need are pointer to cma_kobj? > + cma->kobj->cma = cma; > + if (kobject_init_and_add(&cma->kobj->kobj, &cma_ktype, > + cma_kobj_root, "%s", cma->name)) { CHECK: Alignment should match open parenthesis #382: FILE: mm/cma_sysfs.c:89: + if (kobject_init_and_add(&cma->kobj->kobj, &cma_ktype, + cma_kobj_root, "%s", cma->name)) { > + kobject_put(&cma->kobj->kobj); > + goto out; > + } > + } while (++i < cma_area_count); > + > + return 0; > +out: > + while (--i >= 0) { > + cma = &cma_areas[i]; > + kobject_put(&cma->kobj->kobj); Should the cma->kobj be set to NULL by cma_kobj_release() if cma->kobj is really needed? > + } > + > + kfree(cma_kobjs); > + kobject_put(cma_kobj_root); > + > + return -ENOMEM; > +} > +subsys_initcall(cma_sysfs_init); > Tested-by: Dmitry Osipenko <digetx@xxxxxxxxx>
