[PATCH 18/20] block, blksnap: Kconfig

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 18/20] block, blksnap: Kconfig
Date: Mon, 13 Jun 2022 18:53:11 +0300	[thread overview]
Message-ID: <1655135593-1900-19-git-send-email-sergei.shtepa@veeam.com> (raw)
In-Reply-To: <1655135593-1900-1-git-send-email-sergei.shtepa@veeam.com>

The module configuration file allows you to set default values for
module parameters.

Signed-off-by: Sergei Shtepa <sergei.shtepa@veeam.com>
---
 drivers/block/blksnap/Kconfig | 101 ++++++++++++++++++++++++++++++++++
 1 file changed, 101 insertions(+)
 create mode 100644 drivers/block/blksnap/Kconfig

diff --git a/drivers/block/blksnap/Kconfig b/drivers/block/blksnap/Kconfig
new file mode 100644
index 000000000000..8588a89e30ad
--- /dev/null
+++ b/drivers/block/blksnap/Kconfig
@@ -0,0 +1,101 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# block io layer filter module configuration
+#
+#
+
+config BLK_SNAP
+	tristate "Block device snapshot and change tracker module"
+	depends on BLK_FILTER
+	help
+	  Allow to create snapshots and track block changes for a block
+	  devices. Designed for creating backups for any block devices
+	  (without device mapper). Snapshots are temporary and are released
+	  then backup is completed. Change block tracking allows you to
+	  create incremental or differential backups.
+
+config BLK_SNAP_TRACKING_BLOCK_MINIMUM_SHIFT
+	depends on BLK_SNAP
+	int "The power of 2 for minimum trackings block size"
+	default 16
+	help
+	  The minimum tracking block size by default is 64 KB (shift 16)
+	  It's looks good for block device 128 GB or lower.
+	  In this case, the block device is divided into 2097152 blocks.
+
+config BLK_SNAP_TRACKING_BLOCK_MAXIMUM_COUNT
+	depends on BLK_SNAP
+	int "The limit of the maximum number of trackings blocks"
+	default 2097152
+	help
+	  As the size of the block device grows, the size of the tracking block
+	  size should also grow. For this purpose, the limit of the maximum
+	  number of block size is set.
+
+config BLK_SNAP_CHUNK_MINIMUM_SHIFT
+	depends on BLK_SNAP
+	int "The power of 2 for minimum snapshots chunk size"
+	default 18
+	help
+	  The minimum chunk size by default is 256 KB (shift 18)
+	  It's looks good for block device 128 GB or lower.
+	  In this case, the block device is divided into 524288 chunks.
+
+config BLK_SNAP_CHUNK_MAXIMUM_COUNT
+	depends on BLK_SNAP
+	int "The limit of the maximum number of snapshots chunks"
+	default 2097152
+	help
+	  As the size of the block device grows, the size of the chunk
+	  should also grow. For this purpose, the limit of the maximum number
+	  of chunks is set.
+
+config BLK_SNAP_CHUNK_MAXIMUM_IN_CACHE
+	depends on BLK_SNAP
+	int "The limit of the maximum chunks in memory cache"
+	default 64
+	help
+	  Since reading and writing to snapshots is performed in large chunks,
+	  a cache is implemented to optimize reading small portions of data
+	  from the snapshot image. As the number of chunks in the cache
+	  increases, memory consumption also increases.
+	  The minimum recommended value is four.
+
+config BLK_SNAP_FREE_DIFF_BUFFER_POOL_SIZE
+	depends on BLK_SNAP
+	int "The maximum size of the free buffers pool"
+	default 128
+	help
+	  A buffer can be allocated for each chunk. After use, this buffer is
+	  not released immediately, but is sent to the pool of free buffers.
+	  However, if there are too many free buffers in the pool, they are
+	  released immediately. The maximum size of the pool is regulated by
+	  this define.
+
+config BLK_SNAP_DIFF_STORAGE_MINIMUM
+	depends on BLK_SNAP
+	int "The minimum allowable size of the difference storage in sectors"
+	default 2097152
+	help
+	  When reached, an event is generated about the lack of free space.
+
+config BLK_SNAP_DEBUG_MEMORY_LEAK
+	depends on BLK_SNAP
+	bool "Enable memory leak detector"
+	default n
+	help
+	  Enables debugging code to monitor memory consumption by the module.
+
+	  If unsure, say N.
+
+config BLK_SNAP_ALLOW_DIFF_STORAGE_IN_MEMORY
+	depends on BLK_SNAP
+	bool "Allow difference storage in memory"
+	default n
+	help
+	  Enables the ability to create a repository of changes in memory.
+	  This feature can be useful for debugging. Or it can be used for
+	  mobile phones or other devices if there are guaranteed not to be
+	  a large number of writings during the snapshot hold.
+
+	  If unsure, say N.
-- 
2.20.1

