linux-kernel - [PATCH v4] memblock: Add flags and nid info in memblock debugfs

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Date:   Fri, 19 May 2023 18:53:21 +0800
From:   Yuwei Guan <ssawgyw@...il.com>
To:     rppt@...nel.org, akpm@...ux-foundation.org, tsahu@...ux.ibm.com,
        anshuman.khandual@....com
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Yuwei Guan <ssawgyw@...il.com>
Subject: [PATCH v4] memblock: Add flags and nid info in memblock debugfs

Currently, the memblock debugfs can display the count of memblock_type and
the base and end of the reg. However, when memblock_mark_*() or
memblock_set_node() is executed on some range, the information in the
existing debugfs cannot make it clear why the address is not consecutive.

For example,
cat /sys/kernel/debug/memblock/memory
   0: 0x0000000080000000..0x00000000901fffff
   1: 0x0000000090200000..0x00000000905fffff
   2: 0x0000000090600000..0x0000000092ffffff
   3: 0x0000000093000000..0x00000000973fffff
   4: 0x0000000097400000..0x00000000b71fffff
   5: 0x00000000c0000000..0x00000000dfffffff
   6: 0x00000000e2500000..0x00000000f87fffff
   7: 0x00000000f8800000..0x00000000fa7fffff
   8: 0x00000000fa800000..0x00000000fd3effff
   9: 0x00000000fd3f0000..0x00000000fd3fefff
  10: 0x00000000fd3ff000..0x00000000fd7fffff
  11: 0x00000000fd800000..0x00000000fd901fff
  12: 0x00000000fd902000..0x00000000fd909fff
  13: 0x00000000fd90a000..0x00000000fd90bfff
  14: 0x00000000fd90c000..0x00000000ffffffff
  15: 0x0000000880000000..0x0000000affffffff

So we can add flags and nid to this debugfs.

For example,
cat /sys/kernel/debug/memblock/memory
   0: 0x0000000080000000..0x00000000901fffff    0 NONE
   1: 0x0000000090200000..0x00000000905fffff    0 NOMAP
   2: 0x0000000090600000..0x0000000092ffffff    0 NONE
   3: 0x0000000093000000..0x00000000973fffff    0 NOMAP
   4: 0x0000000097400000..0x00000000b71fffff    0 NONE
   5: 0x00000000c0000000..0x00000000dfffffff    0 NONE
   6: 0x00000000e2500000..0x00000000f87fffff    0 NONE
   7: 0x00000000f8800000..0x00000000fa7fffff    0 NOMAP
   8: 0x00000000fa800000..0x00000000fd3effff    0 NONE
   9: 0x00000000fd3f0000..0x00000000fd3fefff    0 NOMAP
  10: 0x00000000fd3ff000..0x00000000fd7fffff    0 NONE
  11: 0x00000000fd800000..0x00000000fd901fff    0 NOMAP
  12: 0x00000000fd902000..0x00000000fd909fff    0 NONE
  13: 0x00000000fd90a000..0x00000000fd90bfff    0 NOMAP
  14: 0x00000000fd90c000..0x00000000ffffffff    0 NONE
  15: 0x0000000880000000..0x0000000affffffff    0 NONE

Signed-off-by: Yuwei Guan <ssawgyw@...il.com>
---
v4:
- show string value for each memblock flag
---
 mm/memblock.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/mm/memblock.c b/mm/memblock.c
index 511d4783dcf1..10d0ddbeebc1 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -2136,12 +2136,19 @@ void __init memblock_free_all(void)
 }
 
 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_ARCH_KEEP_MEMBLOCK)
+static const char * const flagname[] = {
+	[ilog2(MEMBLOCK_HOTPLUG)] = "HOTPLUG",
+	[ilog2(MEMBLOCK_MIRROR)] = "MIRROR",
+	[ilog2(MEMBLOCK_NOMAP)] = "NOMAP",
+	[ilog2(MEMBLOCK_DRIVER_MANAGED)] = "DRV_MNG",
+};
 
 static int memblock_debug_show(struct seq_file *m, void *private)
 {
 	struct memblock_type *type = m->private;
 	struct memblock_region *reg;
-	int i;
+	int i, j;
+	unsigned int count = ARRAY_SIZE(flagname);
 	phys_addr_t end;
 
 	for (i = 0; i < type->cnt; i++) {
@@ -2149,7 +2156,20 @@ static int memblock_debug_show(struct seq_file *m, void *private)
 		end = reg->base + reg->size - 1;
 
 		seq_printf(m, "%4d: ", i);
-		seq_printf(m, "%pa..%pa\n", &reg->base, &end);
+		seq_printf(m, "%pa..%pa ", &reg->base, &end);
+		seq_printf(m, "%4d ", memblock_get_region_node(reg));
+		if (reg->flags) {
+			for (j = 0; j < count; j++) {
+				if (reg->flags & (1U << j)) {
+					seq_printf(m, "%s\n", flagname[j]);
+					break;
+				}
+			}
+			if (j == count)
+				seq_printf(m, "%s\n", "UNKNOWN");
+		} else {
+			seq_printf(m, "%s\n", "NONE");
+		}
 	}
 	return 0;
 }
-- 
2.34.1