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Subject[PATCH v2 2/5] mm: add numa_count field for rss_stat
Date
This patch add new fields `numa_count` for mm_rss_stat and
task_rss_stat.

`numa_count` are in the size of `sizeof(long) * num_possible_numa()`.
To reduce mem consumption, they only contain the sum of rss which is
needed by `oom_badness` instead of recording different kinds of rss
sepratly.

Signed-off-by: Gang Li <ligang.bdlg@bytedance.com>
---
include/linux/mm_types_task.h | 6 +++
kernel/fork.c | 70 +++++++++++++++++++++++++++++++++--
2 files changed, 73 insertions(+), 3 deletions(-)

diff --git a/include/linux/mm_types_task.h b/include/linux/mm_types_task.h
index 32512af31721..9fd34ab484f4 100644
--- a/include/linux/mm_types_task.h
+++ b/include/linux/mm_types_task.h
@@ -52,11 +52,17 @@ enum {
struct task_rss_stat {
int events; /* for synchronization threshold */
int count[NR_MM_COUNTERS];
+#ifdef CONFIG_NUMA
+ int *numa_count;
+#endif
};
#endif /* USE_SPLIT_PTE_PTLOCKS */

struct mm_rss_stat {
atomic_long_t count[NR_MM_COUNTERS];
+#ifdef CONFIG_NUMA
+ atomic_long_t *numa_count;
+#endif
};

struct page_frag {
diff --git a/kernel/fork.c b/kernel/fork.c
index 23f0ba3affe5..f4f93d6fecd5 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -140,6 +140,10 @@ DEFINE_PER_CPU(unsigned long, process_counts) = 0;

__cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */

+#if (defined SPLIT_RSS_COUNTING) && (defined CONFIG_NUMA)
+#define SPLIT_RSS_NUMA_COUNTING
+#endif
+
#ifdef CONFIG_PROVE_RCU
int lockdep_tasklist_lock_is_held(void)
{
@@ -757,6 +761,16 @@ static void check_mm(struct mm_struct *mm)
mm, resident_page_types[i], x);
}

+#ifdef CONFIG_NUMA
+ for (i = 0; i < num_possible_nodes(); i++) {
+ long x = atomic_long_read(&mm->rss_stat.numa_count[i]);
+
+ if (unlikely(x))
+ pr_alert("BUG: Bad rss-counter state mm:%p node:%d val:%ld\n",
+ mm, i, x);
+ }
+#endif
+
if (mm_pgtables_bytes(mm))
pr_alert("BUG: non-zero pgtables_bytes on freeing mm: %ld\n",
mm_pgtables_bytes(mm));
@@ -769,6 +783,29 @@ static void check_mm(struct mm_struct *mm)
#define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL))
#define free_mm(mm) (kmem_cache_free(mm_cachep, (mm)))

+#ifdef CONFIG_NUMA
+static inline void mm_free_rss_stat(struct mm_struct *mm)
+{
+ kfree(mm->rss_stat.numa_count);
+}
+
+static inline int mm_init_rss_stat(struct mm_struct *mm)
+{
+ memset(&mm->rss_stat.count, 0, sizeof(mm->rss_stat.count));
+ mm->rss_stat.numa_count = kcalloc(num_possible_nodes(), sizeof(atomic_long_t), GFP_KERNEL);
+ if (unlikely(!mm->rss_stat.numa_count))
+ return -ENOMEM;
+ return 0;
+}
+#else
+static inline void mm_free_rss_stat(struct mm_struct *mm) {}
+static inline int mm_init_rss_stat(struct mm_struct *mm)
+{
+ memset(&mm->rss_stat.count, 0, sizeof(mm->rss_stat.count));
+ return 0;
+}
+#endif
+
/*
* Called when the last reference to the mm
* is dropped: either by a lazy thread or by
@@ -783,6 +820,7 @@ void __mmdrop(struct mm_struct *mm)
destroy_context(mm);
mmu_notifier_subscriptions_destroy(mm);
check_mm(mm);
+ mm_free_rss_stat(mm);
put_user_ns(mm->user_ns);
mm_pasid_drop(mm);
free_mm(mm);
@@ -824,12 +862,22 @@ static inline void put_signal_struct(struct signal_struct *sig)
free_signal_struct(sig);
}

+#ifdef SPLIT_RSS_NUMA_COUNTING
+void rss_stat_free(struct task_struct *p)
+{
+ kfree(p->rss_stat.numa_count);
+}
+#else
+void rss_stat_free(struct task_struct *p) {}
+#endif
+
void __put_task_struct(struct task_struct *tsk)
{
WARN_ON(!tsk->exit_state);
WARN_ON(refcount_read(&tsk->usage));
WARN_ON(tsk == current);

+ rss_stat_free(tsk);
io_uring_free(tsk);
cgroup_free(tsk);
task_numa_free(tsk, true);
@@ -956,6 +1004,7 @@ void set_task_stack_end_magic(struct task_struct *tsk)
static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
{
struct task_struct *tsk;
+ int *numa_count __maybe_unused;
int err;

if (node == NUMA_NO_NODE)
@@ -977,9 +1026,16 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
#endif
account_kernel_stack(tsk, 1);

+#ifdef SPLIT_RSS_NUMA_COUNTING
+ numa_count = kcalloc(num_possible_nodes(), sizeof(int), GFP_KERNEL);
+ if (!numa_count)
+ goto free_stack;
+ tsk->rss_stat.numa_count = numa_count;
+#endif
+
err = scs_prepare(tsk, node);
if (err)
- goto free_stack;
+ goto free_rss_stat;

#ifdef CONFIG_SECCOMP
/*
@@ -1045,6 +1101,10 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)

return tsk;

+free_rss_stat:
+#ifdef SPLIT_RSS_NUMA_COUNTING
+ kfree(numa_count);
+#endif
free_stack:
exit_task_stack_account(tsk);
free_thread_stack(tsk);
@@ -1114,7 +1174,6 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
mm->map_count = 0;
mm->locked_vm = 0;
atomic64_set(&mm->pinned_vm, 0);
- memset(&mm->rss_stat, 0, sizeof(mm->rss_stat));
spin_lock_init(&mm->page_table_lock);
spin_lock_init(&mm->arg_lock);
mm_init_cpumask(mm);
@@ -1141,6 +1200,9 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
if (mm_alloc_pgd(mm))
goto fail_nopgd;

+ if (mm_init_rss_stat(mm))
+ goto fail_nocontext;
+
if (init_new_context(p, mm))
goto fail_nocontext;

@@ -2142,7 +2204,9 @@ static __latent_entropy struct task_struct *copy_process(
p->io_uring = NULL;
#endif

-#if defined(SPLIT_RSS_COUNTING)
+#ifdef SPLIT_RSS_NUMA_COUNTING
+ memset(&p->rss_stat, 0, sizeof(p->rss_stat) - sizeof(p->rss_stat.numa_count));
+#else
memset(&p->rss_stat, 0, sizeof(p->rss_stat));
#endif

--
2.20.1
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