a17e203673e998df0e1c6274a358b943cbf2dd2a68794e5e1c60133c.patch

From aa11d788b935a8b86976ffaa822e4ccdea9cf09f Mon Sep 17 00:00:00 2001
From: Bryan Yu <yuholong@google.com>
Date: Wed, 19 Oct 2022 13:31:24 +0900
Subject: [PATCH] CHROMIUM: Reland of add implementation of MGLRU in sysfs

This is a reland of CL:3839069 fixing the memcg bug and snprintf buffer
overflow.
Tested on ARM device with both memcg on and off.
This cherry-pick also contains the changes in CL:4004384.

BUG=b:254153610
TEST=Manual testing on DUT

Signed-off-by: Bryan Yu <yuholong@google.com>
Change-Id: I7dcd354fadda7b4a28c787f6b28dfbce3d1c2f87
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/3965160
Reviewed-by: Suleiman Souhlal <suleiman@chromium.org>
Commit-Queue: Alexandre Marciano Gimenez <raging@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/3998276
Reviewed-by: Alexandre Marciano Gimenez <raging@google.com>
Commit-Queue: Koki Ryu <kokiryu@chromium.org>
Tested-by: Koki Ryu <kokiryu@chromium.org>
Reviewed-by: Koki Ryu <kokiryu@chromium.org>

[rebase61(tzungbi):
    Squashed:
	FIXUP: CHROMIUM: Reland of add implementation of MGLRU in sysfs
]
Signed-off-by: Tzung-Bi Shih <tzungbi@chromium.org>
---
 mm/vmscan.c | 159 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 159 insertions(+)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 9129a0c93f55412f441e05af84db91097f7468d4..d0e86bf3c7c8ca57ccd70cdbe78c117c46431c01 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -5751,6 +5751,15 @@ static void lru_gen_change_state(bool enabled)
  *                          sysfs interface
  ******************************************************************************/
 
+static int run_aging(struct lruvec *lruvec, unsigned long seq, struct scan_control *sc,
+		     bool can_swap, bool force_scan);
+
+static int run_eviction(struct lruvec *lruvec, unsigned long seq, struct scan_control *sc,
+			int swappiness, unsigned long nr_to_reclaim);
+
+static int run_cmd(char cmd, int memcg_id, int nid, unsigned long seq,
+		   struct scan_control *sc, int swappiness, unsigned long opt);
+
 static ssize_t min_ttl_ms_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 {
 	return sysfs_emit(buf, "%u\n", jiffies_to_msecs(READ_ONCE(lru_gen_min_ttl)));
@@ -5818,9 +5827,159 @@ static ssize_t enabled_store(struct kobject *kobj, struct kobj_attribute *attr,
 
 static struct kobj_attribute lru_gen_enabled_attr = __ATTR_RW(enabled);
 
+static int print_node_mglru(struct lruvec *lruvec, char *buf, int orig_pos)
+{
+	unsigned long seq;
+	struct lru_gen_struct *lrugen = &lruvec->lrugen;
+
+	DEFINE_MAX_SEQ(lruvec);
+	DEFINE_MIN_SEQ(lruvec);
+
+	int print_pos = orig_pos;
+
+	seq = min(min_seq[0], min_seq[1]);
+
+	for (; seq <= max_seq; seq++) {
+		int gen, type, zone;
+		unsigned int msecs;
+
+		gen = lru_gen_from_seq(seq);
+		msecs = jiffies_to_msecs(jiffies - READ_ONCE(lrugen->timestamps[gen]));
+
+		print_pos += snprintf(buf + print_pos, PAGE_SIZE - print_pos,
+			" %10lu %10u", seq, msecs);
+
+		for (type = 0; type < ANON_AND_FILE; type++) {
+			long size = 0;
+
+			if (seq < min_seq[type]) {
+				print_pos += snprintf(buf + print_pos,
+					PAGE_SIZE - print_pos, "         -0 ");
+				continue;
+			}
+
+			for (zone = 0; zone < MAX_NR_ZONES; zone++)
+				size += READ_ONCE(lrugen->nr_pages[gen][type][zone]);
+
+			print_pos += snprintf(buf + print_pos,
+				PAGE_SIZE - print_pos, " %10lu ", max(size, 0L));
+		}
+
+		print_pos += snprintf(buf + print_pos, PAGE_SIZE - print_pos, "\n");
+
+	}
+
+	return print_pos - orig_pos;
+}
+
+static ssize_t show_lru_gen_admin(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	struct lruvec *lruvec;
+	struct mem_cgroup *memcg;
+
+	char *path = kvmalloc(PATH_MAX, GFP_KERNEL);
+	int buf_len = 0;
+
+	if (!path)
+		return -EINVAL;
+	path[0] = 0;
+	buf[0] = 0;
+	memcg = mem_cgroup_iter(NULL, NULL, NULL);
+	do {
+		int nid;
+
+		for_each_node_state(nid, N_MEMORY) {
+			lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
+			if (lruvec) {
+				if (nid == first_memory_node) {
+#ifdef CONFIG_MEMCG
+					if (memcg)
+						cgroup_path(memcg->css.cgroup, path, PATH_MAX);
+					else
+						path[0] = 0;
+#endif
+					buf_len += snprintf(buf + buf_len, PAGE_SIZE - buf_len,
+						"memcg %5hu %s\n", mem_cgroup_id(memcg), path);
+				}
+
+				buf_len += snprintf(buf + buf_len, PAGE_SIZE - buf_len,
+					" node %5d\n", nid);
+				buf_len += print_node_mglru(lruvec, buf, buf_len);
+			}
+		}
+	} while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)));
+
+	if (buf_len >= PAGE_SIZE)
+		buf_len = PAGE_SIZE - 1;
+	buf[buf_len] = 0;
+
+	kvfree(path);
+
+	return buf_len;
+}
+
+static ssize_t store_lru_gen_admin(struct kobject *kobj, struct kobj_attribute *attr,
+				const char *src, size_t len)
+{
+	void *buf;
+	char *cur, *next;
+	int err = 0;
+	struct scan_control sc = {
+		.may_writepage = true,
+		.may_unmap = true,
+		.may_swap = true,
+		.reclaim_idx = MAX_NR_ZONES - 1,
+		.gfp_mask = GFP_KERNEL,
+	};
+
+	buf = kvmalloc(len + 1, GFP_USER);
+	if (!buf)
+		return -ENOMEM;
+
+	memcpy(buf, src, len);
+
+	next = buf;
+	next[len] = '\0';
+
+	while ((cur = strsep(&next, ",;\n"))) {
+		int n;
+		int end;
+		char cmd;
+		unsigned int memcg_id;
+		unsigned int nid;
+		unsigned long seq;
+		unsigned int swappiness = -1;
+		unsigned long nr_to_reclaim = -1;
+
+		cur = skip_spaces(cur);
+		if (!*cur)
+			continue;
+
+		n = sscanf(cur, "%c %u %u %lu %n %u %n %lu %n", &cmd, &memcg_id, &nid,
+			   &seq, &end, &swappiness, &end, &nr_to_reclaim, &end);
+		if (n < 4 || cur[end]) {
+			err = -EINVAL;
+			break;
+		}
+
+		err = run_cmd(cmd, memcg_id, nid, seq, &sc, swappiness, nr_to_reclaim);
+		if (err)
+			break;
+	}
+
+	kvfree(buf);
+
+	return err ? : len;
+}
+
+static struct kobj_attribute lru_gen_admin_attr = __ATTR(
+	admin, 0644, show_lru_gen_admin, store_lru_gen_admin
+);
+
 static struct attribute *lru_gen_attrs[] = {
 	&lru_gen_min_ttl_attr.attr,
 	&lru_gen_enabled_attr.attr,
+	&lru_gen_admin_attr.attr,
 	NULL
 };
 
-- 
2.38.3