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From:   Muchun Song <songmuchun@bytedance.com>
To:     gregkh@linuxfoundation.org, rafael@kernel.org, adobriyan@gmail.com,
        akpm@linux-foundation.org, hannes@cmpxchg.org, mhocko@kernel.org,
        vdavydov.dev@gmail.com, hughd@google.com, will@kernel.org,
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        iamjoonsoo.kim@lge.com
Cc:     linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-mm@kvack.org, cgroups@vger.kernel.org,
        Muchun Song <songmuchun@bytedance.com>
Subject: [RESEND PATCH v2 11/12] mm: memcontrol: make the slab calculation consistent
Date:   Sun,  6 Dec 2020 18:14:50 +0800
Message-Id: <20201206101451.14706-12-songmuchun@bytedance.com>
In-Reply-To: <20201206101451.14706-1-songmuchun@bytedance.com>
References: <20201206101451.14706-1-songmuchun@bytedance.com>
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Although the ratio of the slab is one, we also should read the ratio
from the related memory_stats instead of hard-coding. And the local
variable of size is already the value of slab_unreclaimable. So we
do not need to read again.

The unit of the vmstat counters are either pages or bytes now. So we
can drop the ratio in struct memory_stat. This can make the code clean
and simple. And get rid of the awkward mix of static and runtime
initialization of the memory_stats table.

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
 mm/memcontrol.c | 108 ++++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 70 insertions(+), 38 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 48d70c1ad301..49fbcf003bf5 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1493,48 +1493,71 @@ static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
 
 struct memory_stat {
 	const char *name;
-	unsigned int ratio;
 	unsigned int idx;
 };
 
 static const struct memory_stat memory_stats[] = {
-	{ "anon", PAGE_SIZE, NR_ANON_MAPPED },
-	{ "file", PAGE_SIZE, NR_FILE_PAGES },
-	{ "kernel_stack", 1, NR_KERNEL_STACK_B },
-	{ "percpu", 1, MEMCG_PERCPU_B },
-	{ "sock", PAGE_SIZE, MEMCG_SOCK },
-	{ "shmem", PAGE_SIZE, NR_SHMEM },
-	{ "file_mapped", PAGE_SIZE, NR_FILE_MAPPED },
-	{ "file_dirty", PAGE_SIZE, NR_FILE_DIRTY },
-	{ "file_writeback", PAGE_SIZE, NR_WRITEBACK },
+	{ "anon",			NR_ANON_MAPPED			},
+	{ "file",			NR_FILE_PAGES			},
+	{ "kernel_stack",		NR_KERNEL_STACK_B		},
+	{ "percpu",			MEMCG_PERCPU_B			},
+	{ "sock",			MEMCG_SOCK			},
+	{ "shmem",			NR_SHMEM			},
+	{ "file_mapped",		NR_FILE_MAPPED			},
+	{ "file_dirty",			NR_FILE_DIRTY			},
+	{ "file_writeback",		NR_WRITEBACK			},
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-	{ "anon_thp", PAGE_SIZE, NR_ANON_THPS },
-	{ "file_thp", PAGE_SIZE, NR_FILE_THPS },
-	{ "shmem_thp", PAGE_SIZE, NR_SHMEM_THPS },
+	{ "anon_thp",			NR_ANON_THPS			},
+	{ "file_thp",			NR_FILE_THPS			},
+	{ "shmem_thp",			NR_SHMEM_THPS			},
 #endif
-	{ "inactive_anon", PAGE_SIZE, NR_INACTIVE_ANON },
-	{ "active_anon", PAGE_SIZE, NR_ACTIVE_ANON },
-	{ "inactive_file", PAGE_SIZE, NR_INACTIVE_FILE },
-	{ "active_file", PAGE_SIZE, NR_ACTIVE_FILE },
-	{ "unevictable", PAGE_SIZE, NR_UNEVICTABLE },
-
-	/*
-	 * Note: The slab_reclaimable and slab_unreclaimable must be
-	 * together and slab_reclaimable must be in front.
-	 */
-	{ "slab_reclaimable", 1, NR_SLAB_RECLAIMABLE_B },
-	{ "slab_unreclaimable", 1, NR_SLAB_UNRECLAIMABLE_B },
+	{ "inactive_anon",		NR_INACTIVE_ANON		},
+	{ "active_anon",		NR_ACTIVE_ANON			},
+	{ "inactive_file",		NR_INACTIVE_FILE		},
+	{ "active_file",		NR_ACTIVE_FILE			},
+	{ "unevictable",		NR_UNEVICTABLE			},
+	{ "slab_reclaimable",		NR_SLAB_RECLAIMABLE_B		},
+	{ "slab_unreclaimable",		NR_SLAB_UNRECLAIMABLE_B		},
 
 	/* The memory events */
-	{ "workingset_refault_anon", 1, WORKINGSET_REFAULT_ANON },
-	{ "workingset_refault_file", 1, WORKINGSET_REFAULT_FILE },
-	{ "workingset_activate_anon", 1, WORKINGSET_ACTIVATE_ANON },
-	{ "workingset_activate_file", 1, WORKINGSET_ACTIVATE_FILE },
-	{ "workingset_restore_anon", 1, WORKINGSET_RESTORE_ANON },
-	{ "workingset_restore_file", 1, WORKINGSET_RESTORE_FILE },
-	{ "workingset_nodereclaim", 1, WORKINGSET_NODERECLAIM },
+	{ "workingset_refault_anon",	WORKINGSET_REFAULT_ANON		},
+	{ "workingset_refault_file",	WORKINGSET_REFAULT_FILE		},
+	{ "workingset_activate_anon",	WORKINGSET_ACTIVATE_ANON	},
+	{ "workingset_activate_file",	WORKINGSET_ACTIVATE_FILE	},
+	{ "workingset_restore_anon",	WORKINGSET_RESTORE_ANON		},
+	{ "workingset_restore_file",	WORKINGSET_RESTORE_FILE		},
+	{ "workingset_nodereclaim",	WORKINGSET_NODERECLAIM		},
 };
 
+/* Translate stat items to the correct unit for memory.stat output */
+static int memcg_page_state_unit(int item)
+{
+	int unit;
+
+	switch (item) {
+	case WORKINGSET_REFAULT_ANON:
+	case WORKINGSET_REFAULT_FILE:
+	case WORKINGSET_ACTIVATE_ANON:
+	case WORKINGSET_ACTIVATE_FILE:
+	case WORKINGSET_RESTORE_ANON:
+	case WORKINGSET_RESTORE_FILE:
+	case WORKINGSET_NODERECLAIM:
+		unit = 1;
+		break;
+	default:
+		unit = memcg_stat_item_in_bytes(item) ? 1 : PAGE_SIZE;
+		break;
+	}
+
+	return unit;
+}
+
+static inline unsigned long memcg_page_state_output(struct mem_cgroup *memcg,
+						    int item)
+{
+	return memcg_page_state(memcg, item) * memcg_page_state_unit(item);
+}
+
 static char *memory_stat_format(struct mem_cgroup *memcg)
 {
 	struct seq_buf s;
@@ -1558,13 +1581,16 @@ static char *memory_stat_format(struct mem_cgroup *memcg)
 	for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
 		u64 size;
 
-		size = memcg_page_state(memcg, memory_stats[i].idx);
-		size *= memory_stats[i].ratio;
+		size = memcg_page_state_output(memcg, memory_stats[i].idx);
 		seq_buf_printf(&s, "%s %llu\n", memory_stats[i].name, size);
 
+		/*
+		 * We are printing reclaimable, unreclaimable of the slab
+		 * and the sum of both.
+		 */
 		if (unlikely(memory_stats[i].idx == NR_SLAB_UNRECLAIMABLE_B)) {
-			size = memcg_page_state(memcg, NR_SLAB_RECLAIMABLE_B) +
-			       memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE_B);
+			size += memcg_page_state_output(memcg,
+							NR_SLAB_RECLAIMABLE_B);
 			seq_buf_printf(&s, "slab %llu\n", size);
 		}
 	}
@@ -6358,6 +6384,12 @@ static int memory_stat_show(struct seq_file *m, void *v)
 }
 
 #ifdef CONFIG_NUMA
+static inline unsigned long lruvec_page_state_output(struct lruvec *lruvec,
+						     int item)
+{
+	return lruvec_page_state(lruvec, item) * memcg_page_state_unit(item);
+}
+
 static int memory_numa_stat_show(struct seq_file *m, void *v)
 {
 	int i;
@@ -6375,8 +6407,8 @@ static int memory_numa_stat_show(struct seq_file *m, void *v)
 			struct lruvec *lruvec;
 
 			lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
-			size = lruvec_page_state(lruvec, memory_stats[i].idx);
-			size *= memory_stats[i].ratio;
+			size = lruvec_page_state_output(lruvec,
+							memory_stats[i].idx);
 			seq_printf(m, " N%d=%llu", nid, size);
 		}
 		seq_putc(m, '\n');
-- 
2.11.0