mm: deduplicate cacheline padding code

There are three users (mmzone.h, memcontrol.h, page_counter.h) using
similar code for forcing cacheline padding between fields of different
structures.  Dedup that code.

Link: https://lkml.kernel.org/r/20220826230642.566725-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Suggested-by: Feng Tang <feng.tang@intel.com>
Reviewed-by: Feng Tang <feng.tang@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Shakeel Butt 2022-08-26 23:06:42 +00:00 committed by Andrew Morton
parent 974f4367dd
commit e6ad640bc4
4 changed files with 22 additions and 41 deletions

View file

@ -85,4 +85,17 @@
#define cache_line_size() L1_CACHE_BYTES
#endif
/*
* Helper to add padding within a struct to ensure data fall into separate
* cachelines.
*/
#if defined(CONFIG_SMP)
struct cacheline_padding {
char x[0];
} ____cacheline_internodealigned_in_smp;
#define CACHELINE_PADDING(name) struct cacheline_padding name
#else
#define CACHELINE_PADDING(name)
#endif
#endif /* __LINUX_CACHE_H */

View file

@ -185,15 +185,6 @@ struct mem_cgroup_thresholds {
struct mem_cgroup_threshold_ary *spare;
};
#if defined(CONFIG_SMP)
struct memcg_padding {
char x[0];
} ____cacheline_internodealigned_in_smp;
#define MEMCG_PADDING(name) struct memcg_padding name
#else
#define MEMCG_PADDING(name)
#endif
/*
* Remember four most recent foreign writebacks with dirty pages in this
* cgroup. Inode sharing is expected to be uncommon and, even if we miss
@ -304,7 +295,7 @@ struct mem_cgroup {
spinlock_t move_lock;
unsigned long move_lock_flags;
MEMCG_PADDING(_pad1_);
CACHELINE_PADDING(_pad1_);
/* memory.stat */
struct memcg_vmstats vmstats;
@ -326,7 +317,7 @@ struct mem_cgroup {
struct list_head objcg_list;
#endif
MEMCG_PADDING(_pad2_);
CACHELINE_PADDING(_pad2_);
/*
* set > 0 if pages under this cgroup are moving to other cgroup.

View file

@ -121,20 +121,6 @@ static inline bool free_area_empty(struct free_area *area, int migratetype)
struct pglist_data;
/*
* Add a wild amount of padding here to ensure data fall into separate
* cachelines. There are very few zone structures in the machine, so space
* consumption is not a concern here.
*/
#if defined(CONFIG_SMP)
struct zone_padding {
char x[0];
} ____cacheline_internodealigned_in_smp;
#define ZONE_PADDING(name) struct zone_padding name;
#else
#define ZONE_PADDING(name)
#endif
#ifdef CONFIG_NUMA
enum numa_stat_item {
NUMA_HIT, /* allocated in intended node */
@ -837,7 +823,7 @@ struct zone {
int initialized;
/* Write-intensive fields used from the page allocator */
ZONE_PADDING(_pad1_)
CACHELINE_PADDING(_pad1_);
/* free areas of different sizes */
struct free_area free_area[MAX_ORDER];
@ -849,7 +835,7 @@ struct zone {
spinlock_t lock;
/* Write-intensive fields used by compaction and vmstats. */
ZONE_PADDING(_pad2_)
CACHELINE_PADDING(_pad2_);
/*
* When free pages are below this point, additional steps are taken
@ -886,7 +872,7 @@ struct zone {
bool contiguous;
ZONE_PADDING(_pad3_)
CACHELINE_PADDING(_pad3_);
/* Zone statistics */
atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
atomic_long_t vm_numa_event[NR_VM_NUMA_EVENT_ITEMS];
@ -1196,7 +1182,7 @@ typedef struct pglist_data {
#endif /* CONFIG_NUMA */
/* Write-intensive fields used by page reclaim */
ZONE_PADDING(_pad1_)
CACHELINE_PADDING(_pad1_);
#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
/*
@ -1241,7 +1227,7 @@ typedef struct pglist_data {
struct lru_gen_mm_walk mm_walk;
#endif
ZONE_PADDING(_pad2_)
CACHELINE_PADDING(_pad2_);
/* Per-node vmstats */
struct per_cpu_nodestat __percpu *per_cpu_nodestats;

View file

@ -7,22 +7,13 @@
#include <linux/kernel.h>
#include <asm/page.h>
#if defined(CONFIG_SMP)
struct pc_padding {
char x[0];
} ____cacheline_internodealigned_in_smp;
#define PC_PADDING(name) struct pc_padding name
#else
#define PC_PADDING(name)
#endif
struct page_counter {
/*
* Make sure 'usage' does not share cacheline with any other field. The
* memcg->memory.usage is a hot member of struct mem_cgroup.
*/
atomic_long_t usage;
PC_PADDING(_pad1_);
CACHELINE_PADDING(_pad1_);
/* effective memory.min and memory.min usage tracking */
unsigned long emin;
@ -38,7 +29,7 @@ struct page_counter {
unsigned long failcnt;
/* Keep all the read most fields in a separete cacheline. */
PC_PADDING(_pad2_);
CACHELINE_PADDING(_pad2_);
unsigned long min;
unsigned long low;