hulk inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I8OIQR

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Add control file "memory.ksm" to enable ksm per cgroup. Echo to 1 will set all tasks currently in the cgroup to ksm merge any mode, which means ksm gets enabled for all vma's of a process. Meanwhile echo to 0 will disable ksm for them and unmerge the merged pages. Cat the file will show the above state and ksm related profits of this cgroup.

Signed-off-by: Nanyong Sun sunnanyong@huawei.com --- .../admin-guide/cgroup-v1/memory.rst | 1 + mm/memcontrol.c | 110 +++++++++++++++++- 2 files changed, 109 insertions(+), 2 deletions(-)

diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst index edd795855d68..66ae60dead2e 100644 --- a/Documentation/admin-guide/cgroup-v1/memory.rst +++ b/Documentation/admin-guide/cgroup-v1/memory.rst @@ -109,6 +109,7 @@ Brief summary of control files. memory.kmem.tcp.failcnt show the number of tcp buf memory usage hits limits memory.kmem.tcp.max_usage_in_bytes show max tcp buf memory usage recorded + memory.ksm set/show ksm merge any mode ==================================== ==========================================

1. History diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 1f3b893bb576..e5782248749d 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -73,6 +73,7 @@ #include <linux/uaccess.h>

#include <trace/events/vmscan.h> +#include <linux/ksm.h>

struct cgroup_subsys memory_cgrp_subsys __read_mostly; EXPORT_SYMBOL(memory_cgrp_subsys); @@ -242,10 +243,15 @@ enum res_type { iter != NULL; \ iter = mem_cgroup_iter(NULL, iter, NULL))

+static inline bool __task_is_dying(struct task_struct *task) +{ + return tsk_is_oom_victim(task) || fatal_signal_pending(task) || + (task->flags & PF_EXITING); +} + static inline bool task_is_dying(void) { - return tsk_is_oom_victim(current) || fatal_signal_pending(current) || - (current->flags & PF_EXITING); + return __task_is_dying(current); }

/* Some nice accessors for the vmpressure. */ @@ -5101,6 +5107,98 @@ static int mem_cgroup_slab_show(struct seq_file *m, void *p) } #endif

+#ifdef CONFIG_KSM +static int memcg_set_ksm_for_tasks(struct mem_cgroup *memcg, bool enable) +{ + struct task_struct *task; + struct mm_struct *mm; + struct css_task_iter it; + int ret = 0; + + css_task_iter_start(&memcg->css, CSS_TASK_ITER_PROCS, &it); + while (!ret && (task = css_task_iter_next(&it))) { + if (__task_is_dying(task)) + continue; + + mm = get_task_mm(task); + if (!mm) + continue; + + if (mmap_write_lock_killable(mm)) { + mmput(mm); + continue; + } + + if (enable) + ret = ksm_enable_merge_any(mm); + else + ret = ksm_disable_merge_any(mm); + + mmap_write_unlock(mm); + mmput(mm); + } + css_task_iter_end(&it); + + return ret; +} + +static int memory_ksm_show(struct seq_file *m, void *v) +{ + unsigned long ksm_merging_pages = 0; + unsigned long ksm_rmap_items = 0; + long ksm_process_profits = 0; + unsigned int tasks = 0; + struct task_struct *task; + struct mm_struct *mm; + struct css_task_iter it; + struct mem_cgroup *memcg = mem_cgroup_from_seq(m); + + css_task_iter_start(&memcg->css, CSS_TASK_ITER_PROCS, &it); + while ((task = css_task_iter_next(&it))) { + mm = get_task_mm(task); + if (!mm) + continue; + + if (test_bit(MMF_VM_MERGE_ANY, &mm->flags)) + tasks++; + + ksm_rmap_items += mm->ksm_rmap_items; + ksm_merging_pages += mm->ksm_merging_pages; + ksm_process_profits += ksm_process_profit(mm); + mmput(mm); + } + css_task_iter_end(&it); + + seq_printf(m, "merge any tasks: %u\n", tasks); + seq_printf(m, "ksm_rmap_items %lu\n", ksm_rmap_items); + seq_printf(m, "ksm_merging_pages %lu\n", ksm_merging_pages); + seq_printf(m, "ksm_process_profits %ld\n", ksm_process_profits); + return 0; +} + +static ssize_t memory_ksm_write(struct kernfs_open_file *of, char *buf, + size_t nbytes, loff_t off) +{ + bool enable; + int err; + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + + buf = strstrip(buf); + if (!buf) + return -EINVAL; + + err = kstrtobool(buf, &enable); + if (err) + return err; + + err = memcg_set_ksm_for_tasks(memcg, enable); + if (err) + return err; + + return nbytes; +} +#endif /* CONFIG_KSM */ + static int memory_stat_show(struct seq_file *m, void *v);

#ifdef CONFIG_MEMCG_V1_RECLAIM @@ -5417,6 +5515,14 @@ static struct cftype mem_cgroup_legacy_files[] = { .seq_show = wb_blkio_show, .write = wb_blkio_write, }, +#endif +#ifdef CONFIG_KSM + { + .name = "ksm", + .flags = CFTYPE_NOT_ON_ROOT, + .write = memory_ksm_write, + .seq_show = memory_ksm_show, + }, #endif { }, /* terminate */ };