Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Sergei Shtepa <sergei.shtepa@veeam.com>
To:     <axboe@kernel.dk>, <linux-block@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
CC:     Sergei Shtepa <sergei.shtepa@veeam.com>
Subject: [PATCH 17/20] block, blksnap: debugging mechanism for monitoring memory consumption
Date:   Mon, 13 Jun 2022 18:53:10 +0300
Message-ID: <1655135593-1900-18-git-send-email-sergei.shtepa@veeam.com>
In-Reply-To: <1655135593-1900-1-git-send-email-sergei.shtepa@veeam.com>
References: <1655135593-1900-1-git-send-email-sergei.shtepa@veeam.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Of course, the kernel contains mechanisms for detecting memory leaks.
There are tools for monitoring memory consumption. However, this
mechanism turned out to be very simple and convenient for debugging,
and therefore it was decided to leave it in the current version.

Signed-off-by: Sergei Shtepa <sergei.shtepa@veeam.com>
---
 drivers/block/blksnap/memory_checker.c | 100 +++++++++++++++++++++++++
 drivers/block/blksnap/memory_checker.h |  41 ++++++++++
 2 files changed, 141 insertions(+)
 create mode 100644 drivers/block/blksnap/memory_checker.c
 create mode 100644 drivers/block/blksnap/memory_checker.h

diff --git a/drivers/block/blksnap/memory_checker.c b/drivers/block/blksnap/memory_checker.c
new file mode 100644
index 000000000000..96988ed99f08
--- /dev/null
+++ b/drivers/block/blksnap/memory_checker.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifdef CONFIG_BLK_SNAP_DEBUG_MEMORY_LEAK
+#define pr_fmt(fmt) KBUILD_MODNAME "-memory_checker: " fmt
+#include <linux/atomic.h>
+#include <linux/module.h>
+#include "memory_checker.h"
+
+char *memory_object_names[] = {
+	/*alloc_page*/
+	"page",
+	/*kzalloc*/
+	"cbt_map",
+	"chunk",
+	"blk_snap_snaphot_event",
+	"diff_area",
+	"big_buffer",
+	"diff_io",
+	"diff_storage",
+	"storage_bdev",
+	"storage_block",
+	"diff_region",
+	"diff_buffer",
+	"event",
+	"snapimage",
+	"snapshot",
+	"tracker",
+	"tracked_device",
+	/*kcalloc*/
+	"blk_snap_cbt_info",
+	"blk_snap_block_range",
+	"blk_snap_dev_t",
+	"tracker_array",
+	"snapimage_array",
+	"superblock_array",
+	"blk_snap_image_info",
+	/*end*/
+};
+
+static_assert(
+	sizeof(memory_object_names) == (memory_object_count * sizeof(char *)),
+	"The size of enum memory_object_type is not equal to size of memory_object_names array.");
+
+static atomic_t memory_counter[memory_object_count];
+static atomic_t memory_counter_max[memory_object_count];
+
+void memory_object_inc(enum memory_object_type type)
+{
+	int value;
+
+	if (unlikely(type >= memory_object_count))
+		return;
+
+	value = atomic_inc_return(&memory_counter[type]);
+	if (value > atomic_read(&memory_counter_max[type]))
+		atomic_inc(&memory_counter_max[type]);
+}
+
+void memory_object_dec(enum memory_object_type type)
+{
+	if (unlikely(type >= memory_object_count))
+		return;
+
+	atomic_dec(&memory_counter[type]);
+}
+
+int memory_object_print(void)
+{
+	int inx;
+	int not_free = 0;
+
+	pr_info("Objects in memory:\n");
+	for (inx = 0; inx < memory_object_count; inx++) {
+		int count = atomic_read(&memory_counter[inx]);
+
+		if (count) {
+			not_free += count;
+			pr_info("%s: %d\n", memory_object_names[inx], count);
+		}
+	}
+	if (not_free)
+		pr_info("Found %d allocated objects\n", not_free);
+	else
+		pr_info("All objects have been released\n");
+	return not_free;
+}
+
+void memory_object_max_print(void)
+{
+	int inx;
+
+	pr_info("Maximim objects in memory:\n");
+	for (inx = 0; inx < memory_object_count; inx++) {
+		int count = atomic_read(&memory_counter_max[inx]);
+
+		if (count)
+			pr_info("%s: %d\n", memory_object_names[inx], count);
+	}
+	pr_info(".\n");
+}
+#endif
diff --git a/drivers/block/blksnap/memory_checker.h b/drivers/block/blksnap/memory_checker.h
new file mode 100644
index 000000000000..b19a2584d0ce
--- /dev/null
+++ b/drivers/block/blksnap/memory_checker.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#pragma once
+#ifdef CONFIG_BLK_SNAP_DEBUG_MEMORY_LEAK
+
+enum memory_object_type {
+	/*alloc_page*/
+	memory_object_page,
+	/*kzalloc*/
+	memory_object_cbt_map,
+	memory_object_chunk,
+	memory_object_blk_snap_snapshot_event,
+	memory_object_diff_area,
+	memory_object_big_buffer,
+	memory_object_diff_io,
+	memory_object_diff_storage,
+	memory_object_storage_bdev,
+	memory_object_storage_block,
+	memory_object_diff_region,
+	memory_object_diff_buffer,
+	memory_object_event,
+	memory_object_snapimage,
+	memory_object_snapshot,
+	memory_object_tracker,
+	memory_object_tracked_device,
+	/*kcalloc*/
+	memory_object_blk_snap_cbt_info,
+	memory_object_blk_snap_block_range,
+	memory_object_blk_snap_dev_t,
+	memory_object_tracker_array,
+	memory_object_snapimage_array,
+	memory_object_superblock_array,
+	memory_object_blk_snap_image_info,
+	/*end*/
+	memory_object_count
+};
+
+void memory_object_inc(enum memory_object_type type);
+void memory_object_dec(enum memory_object_type type);
+int  memory_object_print(void);
+void memory_object_max_print(void);
+#endif
-- 
2.20.1