From: Jianyue Wu Replace seq_printf/seq_buf_printf with lightweight helpers to avoid printf parsing in memcg stats output. Key changes: - Add memcg_seq_put_name_val() for seq_file "name value\n" formatting - Add memcg_seq_buf_put_name_val() for seq_buf "name value\n" formatting - Update __memory_events_show(), swap_events_show(), memory_stat_format(), memory_numa_stat_show(), and related helpers - Introduce local variables to improve readability and reduce line length Performance: - 1M reads of memory.stat+memory.numa_stat - Before: real 0m9.663s, user 0m4.840s, sys 0m4.823s - After: real 0m9.051s, user 0m4.775s, sys 0m4.275s (~11.4% sys drop) Tests: - Script: for ((i=1; i<=1000000; i++)); do : > /dev/null < /sys/fs/cgroup/memory.stat : > /dev/null < /sys/fs/cgroup/memory.numa_stat done Signed-off-by: Jianyue Wu --- Changes in v2: - Fixed indentation issues - Added local variables in helper functions to improve code readability and avoid overly long parameter lines v1: Initial submission mm/memcontrol-v1.c | 120 ++++++++++++++++++++++++++++----------------- mm/memcontrol-v1.h | 34 +++++++++++++ mm/memcontrol.c | 102 +++++++++++++++++++++++--------------- 3 files changed, 173 insertions(+), 83 deletions(-) diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c index 6eed14bff742..482475333876 100644 --- a/mm/memcontrol-v1.c +++ b/mm/memcontrol-v1.c @@ -10,7 +10,7 @@ #include #include #include -#include +#include #include "internal.h" #include "swap.h" @@ -1795,25 +1795,36 @@ static int memcg_numa_stat_show(struct seq_file *m, void *v) mem_cgroup_flush_stats(memcg); for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { - seq_printf(m, "%s=%lu", stat->name, - mem_cgroup_nr_lru_pages(memcg, stat->lru_mask, - false)); - for_each_node_state(nid, N_MEMORY) - seq_printf(m, " N%d=%lu", nid, - mem_cgroup_node_nr_lru_pages(memcg, nid, - stat->lru_mask, false)); + u64 nr_pages; + + seq_puts(m, stat->name); + nr_pages = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask, + false); + seq_put_decimal_ull(m, "=", nr_pages); + for_each_node_state(nid, N_MEMORY) { + nr_pages = mem_cgroup_node_nr_lru_pages(memcg, nid, + stat->lru_mask, + false); + seq_put_decimal_ull(m, " N", nid); + seq_put_decimal_ull(m, "=", nr_pages); + } seq_putc(m, '\n'); } for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { - - seq_printf(m, "hierarchical_%s=%lu", stat->name, - mem_cgroup_nr_lru_pages(memcg, stat->lru_mask, - true)); - for_each_node_state(nid, N_MEMORY) - seq_printf(m, " N%d=%lu", nid, - mem_cgroup_node_nr_lru_pages(memcg, nid, - stat->lru_mask, true)); + u64 nr_pages; + + seq_puts(m, "hierarchical_"); + seq_puts(m, stat->name); + nr_pages = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask, true); + seq_put_decimal_ull(m, "=", nr_pages); + for_each_node_state(nid, N_MEMORY) { + nr_pages = mem_cgroup_node_nr_lru_pages(memcg, nid, + stat->lru_mask, + true); + seq_put_decimal_ull(m, " N", nid); + seq_put_decimal_ull(m, "=", nr_pages); + } seq_putc(m, '\n'); } @@ -1870,6 +1881,7 @@ void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s) unsigned long memory, memsw; struct mem_cgroup *mi; unsigned int i; + u64 memory_limit, memsw_limit; BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names) != ARRAY_SIZE(memcg1_stats)); @@ -1879,17 +1891,24 @@ void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s) unsigned long nr; nr = memcg_page_state_local_output(memcg, memcg1_stats[i]); - seq_buf_printf(s, "%s %lu\n", memcg1_stat_names[i], nr); + memcg_seq_buf_put_name_val(s, memcg1_stat_names[i], (u64)nr); } - for (i = 0; i < ARRAY_SIZE(memcg1_events); i++) - seq_buf_printf(s, "%s %lu\n", vm_event_name(memcg1_events[i]), - memcg_events_local(memcg, memcg1_events[i])); + for (i = 0; i < ARRAY_SIZE(memcg1_events); i++) { + u64 events; - for (i = 0; i < NR_LRU_LISTS; i++) - seq_buf_printf(s, "%s %lu\n", lru_list_name(i), - memcg_page_state_local(memcg, NR_LRU_BASE + i) * - PAGE_SIZE); + events = memcg_events_local(memcg, memcg1_events[i]); + memcg_seq_buf_put_name_val(s, vm_event_name(memcg1_events[i]), + events); + } + + for (i = 0; i < NR_LRU_LISTS; i++) { + u64 nr_pages; + + nr_pages = memcg_page_state_local(memcg, NR_LRU_BASE + i) * + PAGE_SIZE; + memcg_seq_buf_put_name_val(s, lru_list_name(i), nr_pages); + } /* Hierarchical information */ memory = memsw = PAGE_COUNTER_MAX; @@ -1897,28 +1916,38 @@ void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s) memory = min(memory, READ_ONCE(mi->memory.max)); memsw = min(memsw, READ_ONCE(mi->memsw.max)); } - seq_buf_printf(s, "hierarchical_memory_limit %llu\n", - (u64)memory * PAGE_SIZE); - seq_buf_printf(s, "hierarchical_memsw_limit %llu\n", - (u64)memsw * PAGE_SIZE); + memory_limit = (u64)memory * PAGE_SIZE; + memsw_limit = (u64)memsw * PAGE_SIZE; + + memcg_seq_buf_put_name_val(s, "hierarchical_memory_limit", + memory_limit); + memcg_seq_buf_put_name_val(s, "hierarchical_memsw_limit", + memsw_limit); for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) { unsigned long nr; nr = memcg_page_state_output(memcg, memcg1_stats[i]); - seq_buf_printf(s, "total_%s %llu\n", memcg1_stat_names[i], - (u64)nr); + seq_buf_puts(s, "total_"); + memcg_seq_buf_put_name_val(s, memcg1_stat_names[i], (u64)nr); + } + + for (i = 0; i < ARRAY_SIZE(memcg1_events); i++) { + u64 events; + + events = memcg_events(memcg, memcg1_events[i]); + seq_buf_puts(s, "total_"); + memcg_seq_buf_put_name_val(s, vm_event_name(memcg1_events[i]), + events); } - for (i = 0; i < ARRAY_SIZE(memcg1_events); i++) - seq_buf_printf(s, "total_%s %llu\n", - vm_event_name(memcg1_events[i]), - (u64)memcg_events(memcg, memcg1_events[i])); + for (i = 0; i < NR_LRU_LISTS; i++) { + u64 nr_pages; - for (i = 0; i < NR_LRU_LISTS; i++) - seq_buf_printf(s, "total_%s %llu\n", lru_list_name(i), - (u64)memcg_page_state(memcg, NR_LRU_BASE + i) * - PAGE_SIZE); + nr_pages = memcg_page_state(memcg, NR_LRU_BASE + i) * PAGE_SIZE; + seq_buf_puts(s, "total_"); + memcg_seq_buf_put_name_val(s, lru_list_name(i), nr_pages); + } #ifdef CONFIG_DEBUG_VM { @@ -1933,8 +1962,8 @@ void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s) anon_cost += mz->lruvec.anon_cost; file_cost += mz->lruvec.file_cost; } - seq_buf_printf(s, "anon_cost %lu\n", anon_cost); - seq_buf_printf(s, "file_cost %lu\n", file_cost); + memcg_seq_buf_put_name_val(s, "anon_cost", (u64)anon_cost); + memcg_seq_buf_put_name_val(s, "file_cost", (u64)file_cost); } #endif } @@ -1968,11 +1997,14 @@ static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css, static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v) { struct mem_cgroup *memcg = mem_cgroup_from_seq(sf); + u64 oom_kill; + + memcg_seq_put_name_val(sf, "oom_kill_disable", + READ_ONCE(memcg->oom_kill_disable)); + memcg_seq_put_name_val(sf, "under_oom", (bool)memcg->under_oom); - seq_printf(sf, "oom_kill_disable %d\n", READ_ONCE(memcg->oom_kill_disable)); - seq_printf(sf, "under_oom %d\n", (bool)memcg->under_oom); - seq_printf(sf, "oom_kill %lu\n", - atomic_long_read(&memcg->memory_events[MEMCG_OOM_KILL])); + oom_kill = atomic_long_read(&memcg->memory_events[MEMCG_OOM_KILL]); + memcg_seq_put_name_val(sf, "oom_kill", oom_kill); return 0; } diff --git a/mm/memcontrol-v1.h b/mm/memcontrol-v1.h index 6358464bb416..a4ac2d869506 100644 --- a/mm/memcontrol-v1.h +++ b/mm/memcontrol-v1.h @@ -4,6 +4,9 @@ #define __MM_MEMCONTROL_V1_H #include +#include +#include +#include /* Cgroup v1 and v2 common declarations */ @@ -33,6 +36,37 @@ int memory_stat_show(struct seq_file *m, void *v); void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n); struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg); +/* Max 2^64 - 1 = 18446744073709551615 (20 digits) */ +#define MEMCG_DEC_U64_MAX_LEN 20 + +static inline void memcg_seq_put_name_val(struct seq_file *m, const char *name, + u64 val) +{ + seq_puts(m, name); + /* need a space between name and value */ + seq_put_decimal_ull(m, " ", val); + seq_putc(m, '\n'); +} + +static inline void memcg_seq_buf_put_name_val(struct seq_buf *s, + const char *name, u64 val) +{ + char num_buf[MEMCG_DEC_U64_MAX_LEN]; + int num_len; + + num_len = num_to_str(num_buf, sizeof(num_buf), val, 0); + if (num_len <= 0) + return; + + if (seq_buf_puts(s, name)) + return; + if (seq_buf_putc(s, ' ')) + return; + if (seq_buf_putmem(s, num_buf, num_len)) + return; + seq_buf_putc(s, '\n'); +} + /* Cgroup v1-specific declarations */ #ifdef CONFIG_MEMCG_V1 diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 86f43b7e5f71..52dde3b8e386 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -42,6 +42,7 @@ #include #include #include +#include #include #include #include @@ -1463,6 +1464,7 @@ static bool memcg_accounts_hugetlb(void) static void memcg_stat_format(struct mem_cgroup *memcg, struct seq_buf *s) { int i; + u64 pgscan, pgsteal; /* * Provide statistics on the state of the memory subsystem as @@ -1485,36 +1487,40 @@ static void memcg_stat_format(struct mem_cgroup *memcg, struct seq_buf *s) continue; #endif size = memcg_page_state_output(memcg, memory_stats[i].idx); - seq_buf_printf(s, "%s %llu\n", memory_stats[i].name, size); + memcg_seq_buf_put_name_val(s, memory_stats[i].name, size); if (unlikely(memory_stats[i].idx == NR_SLAB_UNRECLAIMABLE_B)) { size += memcg_page_state_output(memcg, NR_SLAB_RECLAIMABLE_B); - seq_buf_printf(s, "slab %llu\n", size); + memcg_seq_buf_put_name_val(s, "slab", size); } } /* Accumulated memory events */ - seq_buf_printf(s, "pgscan %lu\n", - memcg_events(memcg, PGSCAN_KSWAPD) + - memcg_events(memcg, PGSCAN_DIRECT) + - memcg_events(memcg, PGSCAN_PROACTIVE) + - memcg_events(memcg, PGSCAN_KHUGEPAGED)); - seq_buf_printf(s, "pgsteal %lu\n", - memcg_events(memcg, PGSTEAL_KSWAPD) + - memcg_events(memcg, PGSTEAL_DIRECT) + - memcg_events(memcg, PGSTEAL_PROACTIVE) + - memcg_events(memcg, PGSTEAL_KHUGEPAGED)); + pgscan = memcg_events(memcg, PGSCAN_KSWAPD) + + memcg_events(memcg, PGSCAN_DIRECT) + + memcg_events(memcg, PGSCAN_PROACTIVE) + + memcg_events(memcg, PGSCAN_KHUGEPAGED); + pgsteal = memcg_events(memcg, PGSTEAL_KSWAPD) + + memcg_events(memcg, PGSTEAL_DIRECT) + + memcg_events(memcg, PGSTEAL_PROACTIVE) + + memcg_events(memcg, PGSTEAL_KHUGEPAGED); + + memcg_seq_buf_put_name_val(s, "pgscan", pgscan); + memcg_seq_buf_put_name_val(s, "pgsteal", pgsteal); for (i = 0; i < ARRAY_SIZE(memcg_vm_event_stat); i++) { + u64 events; + #ifdef CONFIG_MEMCG_V1 if (memcg_vm_event_stat[i] == PGPGIN || memcg_vm_event_stat[i] == PGPGOUT) continue; #endif - seq_buf_printf(s, "%s %lu\n", - vm_event_name(memcg_vm_event_stat[i]), - memcg_events(memcg, memcg_vm_event_stat[i])); + events = memcg_events(memcg, memcg_vm_event_stat[i]); + memcg_seq_buf_put_name_val(s, + vm_event_name(memcg_vm_event_stat[i]), + events); } } @@ -4218,10 +4224,12 @@ static void mem_cgroup_attach(struct cgroup_taskset *tset) static int seq_puts_memcg_tunable(struct seq_file *m, unsigned long value) { - if (value == PAGE_COUNTER_MAX) + if (value == PAGE_COUNTER_MAX) { seq_puts(m, "max\n"); - else - seq_printf(m, "%llu\n", (u64)value * PAGE_SIZE); + } else { + seq_put_decimal_ull(m, "", (u64)value * PAGE_SIZE); + seq_putc(m, '\n'); + } return 0; } @@ -4247,7 +4255,8 @@ static int peak_show(struct seq_file *sf, void *v, struct page_counter *pc) else peak = max(fd_peak, READ_ONCE(pc->local_watermark)); - seq_printf(sf, "%llu\n", peak * PAGE_SIZE); + seq_put_decimal_ull(sf, "", peak * PAGE_SIZE); + seq_putc(sf, '\n'); return 0; } @@ -4480,16 +4489,24 @@ static ssize_t memory_max_write(struct kernfs_open_file *of, */ static void __memory_events_show(struct seq_file *m, atomic_long_t *events) { - seq_printf(m, "low %lu\n", atomic_long_read(&events[MEMCG_LOW])); - seq_printf(m, "high %lu\n", atomic_long_read(&events[MEMCG_HIGH])); - seq_printf(m, "max %lu\n", atomic_long_read(&events[MEMCG_MAX])); - seq_printf(m, "oom %lu\n", atomic_long_read(&events[MEMCG_OOM])); - seq_printf(m, "oom_kill %lu\n", - atomic_long_read(&events[MEMCG_OOM_KILL])); - seq_printf(m, "oom_group_kill %lu\n", - atomic_long_read(&events[MEMCG_OOM_GROUP_KILL])); - seq_printf(m, "sock_throttled %lu\n", - atomic_long_read(&events[MEMCG_SOCK_THROTTLED])); + u64 low, high, max, oom, oom_kill; + u64 oom_group_kill, sock_throttled; + + low = atomic_long_read(&events[MEMCG_LOW]); + high = atomic_long_read(&events[MEMCG_HIGH]); + max = atomic_long_read(&events[MEMCG_MAX]); + oom = atomic_long_read(&events[MEMCG_OOM]); + oom_kill = atomic_long_read(&events[MEMCG_OOM_KILL]); + oom_group_kill = atomic_long_read(&events[MEMCG_OOM_GROUP_KILL]); + sock_throttled = atomic_long_read(&events[MEMCG_SOCK_THROTTLED]); + + memcg_seq_put_name_val(m, "low", low); + memcg_seq_put_name_val(m, "high", high); + memcg_seq_put_name_val(m, "max", max); + memcg_seq_put_name_val(m, "oom", oom); + memcg_seq_put_name_val(m, "oom_kill", oom_kill); + memcg_seq_put_name_val(m, "oom_group_kill", oom_group_kill); + memcg_seq_put_name_val(m, "sock_throttled", sock_throttled); } static int memory_events_show(struct seq_file *m, void *v) @@ -4544,7 +4561,7 @@ static int memory_numa_stat_show(struct seq_file *m, void *v) if (memory_stats[i].idx >= NR_VM_NODE_STAT_ITEMS) continue; - seq_printf(m, "%s", memory_stats[i].name); + seq_puts(m, memory_stats[i].name); for_each_node_state(nid, N_MEMORY) { u64 size; struct lruvec *lruvec; @@ -4552,7 +4569,10 @@ static int memory_numa_stat_show(struct seq_file *m, void *v) lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid)); size = lruvec_page_state_output(lruvec, memory_stats[i].idx); - seq_printf(m, " N%d=%llu", nid, size); + + seq_put_decimal_ull(m, " N", nid); + seq_putc(m, '='); + seq_put_decimal_ull(m, "", size); } seq_putc(m, '\n'); } @@ -4565,7 +4585,8 @@ static int memory_oom_group_show(struct seq_file *m, void *v) { struct mem_cgroup *memcg = mem_cgroup_from_seq(m); - seq_printf(m, "%d\n", READ_ONCE(memcg->oom_group)); + seq_put_decimal_ll(m, "", READ_ONCE(memcg->oom_group)); + seq_putc(m, '\n'); return 0; } @@ -5372,13 +5393,15 @@ static ssize_t swap_max_write(struct kernfs_open_file *of, static int swap_events_show(struct seq_file *m, void *v) { struct mem_cgroup *memcg = mem_cgroup_from_seq(m); + u64 swap_high, swap_max, swap_fail; + + swap_high = atomic_long_read(&memcg->memory_events[MEMCG_SWAP_HIGH]); + swap_max = atomic_long_read(&memcg->memory_events[MEMCG_SWAP_MAX]); + swap_fail = atomic_long_read(&memcg->memory_events[MEMCG_SWAP_FAIL]); - seq_printf(m, "high %lu\n", - atomic_long_read(&memcg->memory_events[MEMCG_SWAP_HIGH])); - seq_printf(m, "max %lu\n", - atomic_long_read(&memcg->memory_events[MEMCG_SWAP_MAX])); - seq_printf(m, "fail %lu\n", - atomic_long_read(&memcg->memory_events[MEMCG_SWAP_FAIL])); + memcg_seq_put_name_val(m, "high", swap_high); + memcg_seq_put_name_val(m, "max", swap_max); + memcg_seq_put_name_val(m, "fail", swap_fail); return 0; } @@ -5564,7 +5587,8 @@ static int zswap_writeback_show(struct seq_file *m, void *v) { struct mem_cgroup *memcg = mem_cgroup_from_seq(m); - seq_printf(m, "%d\n", READ_ONCE(memcg->zswap_writeback)); + seq_put_decimal_ll(m, "", READ_ONCE(memcg->zswap_writeback)); + seq_putc(m, '\n'); return 0; } -- 2.43.0