From 15995a35247442aefa0ffe36a6dad51cb46b0918 Mon Sep 17 00:00:00 2001 From: Sourav Panda Date: Wed, 5 Jun 2024 22:27:51 +0000 Subject: mm: report per-page metadata information Today, we do not have any observability of per-page metadata and how much it takes away from the machine capacity. Thus, we want to describe the amount of memory that is going towards per-page metadata, which can vary depending on build configuration, machine architecture, and system use. This patch adds 2 fields to /proc/vmstat that can used as shown below: Accounting per-page metadata allocated by boot-allocator: /proc/vmstat:nr_memmap_boot * PAGE_SIZE Accounting per-page metadata allocated by buddy-allocator: /proc/vmstat:nr_memmap * PAGE_SIZE Accounting total Perpage metadata allocated on the machine: (/proc/vmstat:nr_memmap_boot + /proc/vmstat:nr_memmap) * PAGE_SIZE Utility for userspace: Observability: Describe the amount of memory overhead that is going to per-page metadata on the system at any given time since this overhead is not currently observable. Debugging: Tracking the changes or absolute value in struct pages can help detect anomalies as they can be correlated with other metrics in the machine (e.g., memtotal, number of huge pages, etc). page_ext overheads: Some kernel features such as page_owner page_table_check that use page_ext can be optionally enabled via kernel parameters. Having the total per-page metadata information helps users precisely measure impact. Furthermore, page-metadata metrics will reflect the amount of struct pages reliquished (or overhead reduced) when hugetlbfs pages are reserved which will vary depending on whether hugetlb vmemmap optimization is enabled or not. For background and results see: lore.kernel.org/all/20240220214558.3377482-1-souravpanda@google.com Link: https://lkml.kernel.org/r/20240605222751.1406125-1-souravpanda@google.com Signed-off-by: Sourav Panda Acked-by: David Rientjes Reviewed-by: Pasha Tatashin Cc: Alexey Dobriyan Cc: Bjorn Helgaas Cc: Chen Linxuan Cc: David Hildenbrand Cc: Greg Kroah-Hartman Cc: Ivan Babrou Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Kefeng Wang Cc: Kirill A. Shutemov Cc: Liam R. Howlett Cc: Mike Kravetz Cc: Mike Rapoport (IBM) Cc: Muchun Song Cc: "Rafael J. Wysocki" Cc: Randy Dunlap Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Tomas Mudrunka Cc: Vlastimil Babka Cc: Wei Xu Cc: Yang Yang Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- include/linux/vmstat.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/vmstat.h') diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h index 735eae6e272c..16b0cfa80502 100644 --- a/include/linux/vmstat.h +++ b/include/linux/vmstat.h @@ -624,4 +624,8 @@ static inline void lruvec_stat_sub_folio(struct folio *folio, { lruvec_stat_mod_folio(folio, idx, -folio_nr_pages(folio)); } + +void __meminit mod_node_early_perpage_metadata(int nid, long delta); +void __meminit store_early_perpage_metadata(void); + #endif /* _LINUX_VMSTAT_H */ -- cgit v1.2.3 From 78eb4ea25cd5fdbdae7eb9fdf87b99195ff67508 Mon Sep 17 00:00:00 2001 From: Joel Granados Date: Wed, 24 Jul 2024 20:59:29 +0200 Subject: sysctl: treewide: constify the ctl_table argument of proc_handlers MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit const qualify the struct ctl_table argument in the proc_handler function signatures. This is a prerequisite to moving the static ctl_table structs into .rodata data which will ensure that proc_handler function pointers cannot be modified. This patch has been generated by the following coccinelle script: ``` virtual patch @r1@ identifier ctl, write, buffer, lenp, ppos; identifier func !~ "appldata_(timer|interval)_handler|sched_(rt|rr)_handler|rds_tcp_skbuf_handler|proc_sctp_do_(hmac_alg|rto_min|rto_max|udp_port|alpha_beta|auth|probe_interval)"; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int write, void *buffer, size_t *lenp, loff_t *ppos); @r2@ identifier func, ctl, write, buffer, lenp, ppos; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int write, void *buffer, size_t *lenp, loff_t *ppos) { ... } @r3@ identifier func; @@ int func( - struct ctl_table * + const struct ctl_table * ,int , void *, size_t *, loff_t *); @r4@ identifier func, ctl; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int , void *, size_t *, loff_t *); @r5@ identifier func, write, buffer, lenp, ppos; @@ int func( - struct ctl_table * + const struct ctl_table * ,int write, void *buffer, size_t *lenp, loff_t *ppos); ``` * Code formatting was adjusted in xfs_sysctl.c to comply with code conventions. The xfs_stats_clear_proc_handler, xfs_panic_mask_proc_handler and xfs_deprecated_dointvec_minmax where adjusted. * The ctl_table argument in proc_watchdog_common was const qualified. This is called from a proc_handler itself and is calling back into another proc_handler, making it necessary to change it as part of the proc_handler migration. Co-developed-by: Thomas Weißschuh Signed-off-by: Thomas Weißschuh Co-developed-by: Joel Granados Signed-off-by: Joel Granados --- include/linux/vmstat.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux/vmstat.h') diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h index 16b0cfa80502..23cd17942036 100644 --- a/include/linux/vmstat.h +++ b/include/linux/vmstat.h @@ -17,7 +17,7 @@ extern int sysctl_stat_interval; #define DISABLE_NUMA_STAT 0 extern int sysctl_vm_numa_stat; DECLARE_STATIC_KEY_TRUE(vm_numa_stat_key); -int sysctl_vm_numa_stat_handler(struct ctl_table *table, int write, +int sysctl_vm_numa_stat_handler(const struct ctl_table *table, int write, void *buffer, size_t *length, loff_t *ppos); #endif @@ -301,7 +301,7 @@ void cpu_vm_stats_fold(int cpu); void refresh_zone_stat_thresholds(void); struct ctl_table; -int vmstat_refresh(struct ctl_table *, int write, void *buffer, size_t *lenp, +int vmstat_refresh(const struct ctl_table *, int write, void *buffer, size_t *lenp, loff_t *ppos); void drain_zonestat(struct zone *zone, struct per_cpu_zonestat *); -- cgit v1.2.3