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From: Coly Li <colyli@suse.de>
To: axboe@kernel.dk
Cc: linux-block@vger.kernel.org, linux-bcache@vger.kernel.org,
	Coly Li <colyli@suse.de>
Subject: [PATCH 21/25] bcache: add bucket_size_hi into struct cache_sb_disk for large bucket
Date: Sat, 25 Jul 2020 20:00:35 +0800	[thread overview]
Message-ID: <20200725120039.91071-22-colyli@suse.de> (raw)
In-Reply-To: <20200725120039.91071-1-colyli@suse.de>

The large bucket feature is to extend bucket_size from 16bit to 32bit.

When create cache device on zoned device (e.g. zoned NVMe SSD), making
a single bucket cover one or more zones of the zoned device is the
simplest way to support zoned device as cache by bcache.

But current maximum bucket size is 16MB and a typical zone size of zoned
device is 256MB, this is the major motiviation to extend bucket size to
a larger bit width.

This patch is the basic and first change to support large bucket size,
the major changes it makes are,
- Add BCH_FEATURE_INCOMPAT_LARGE_BUCKET for the large bucket feature,
  INCOMPAT means it introduces incompatible on-disk format change.
- Add BCH_FEATURE_INCOMPAT_FUNCS(large_bucket, LARGE_BUCKET) routines.
- Adds __le16 bucket_size_hi into struct cache_sb_disk at offset 0x8d0
  for the on-disk super block format.
- For the in-memory super block struct cache_sb, member bucket_size is
  extended from __u16 to __32.
- Add get_bucket_size() to combine the bucket_size and bucket_size_hi
  from struct cache_sb_disk into an unsigned int value.

Since we already have large bucket size helpers meta_bucket_pages(),
meta_bucket_bytes() and alloc_meta_bucket_pages(), they make sure when
bucket size > 8MB, the memory allocation for bcache meta data bucket
won't fail no matter how large the bucket size extended. So these meta
data buckets are handled properly when the bucket size width increase
from 16bit to 32bit, we don't need to worry about them.

Signed-off-by: Coly Li <colyli@suse.de>
---
 drivers/md/bcache/alloc.c    |  2 +-
 drivers/md/bcache/features.c | 22 ++++++++++++++++++++++
 drivers/md/bcache/features.h |  9 ++++++---
 drivers/md/bcache/movinggc.c |  4 ++--
 drivers/md/bcache/super.c    | 23 +++++++++++++++++++----
 include/uapi/linux/bcache.h  |  3 ++-
 6 files changed, 52 insertions(+), 11 deletions(-)
 create mode 100644 drivers/md/bcache/features.c

diff --git a/drivers/md/bcache/alloc.c b/drivers/md/bcache/alloc.c
index a1df0d95151c..52035a78d836 100644
--- a/drivers/md/bcache/alloc.c
+++ b/drivers/md/bcache/alloc.c
@@ -87,7 +87,7 @@ void bch_rescale_priorities(struct cache_set *c, int sectors)
 {
 	struct cache *ca;
 	struct bucket *b;
-	unsigned int next = c->nbuckets * c->sb.bucket_size / 1024;
+	unsigned long next = c->nbuckets * c->sb.bucket_size / 1024;
 	unsigned int i;
 	int r;
 
diff --git a/drivers/md/bcache/features.c b/drivers/md/bcache/features.c
new file mode 100644
index 000000000000..ba53944bb390
--- /dev/null
+++ b/drivers/md/bcache/features.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Feature set bits and string conversion.
+ * Inspired by ext4's features compat/incompat/ro_compat related code.
+ *
+ * Copyright 2020 Coly Li <colyli@suse.de>
+ *
+ */
+#include <linux/bcache.h>
+#include "bcache.h"
+
+struct feature {
+	int		compat;
+	unsigned int	mask;
+	const char	*string;
+};
+
+static struct feature feature_list[] = {
+	{BCH_FEATURE_INCOMPAT, BCH_FEATURE_INCOMPAT_LARGE_BUCKET,
+		"large_bucket"},
+	{0, 0, 0 },
+};
diff --git a/drivers/md/bcache/features.h b/drivers/md/bcache/features.h
index ae7df37b9862..dca052cf5203 100644
--- a/drivers/md/bcache/features.h
+++ b/drivers/md/bcache/features.h
@@ -11,9 +11,13 @@
 #define BCH_FEATURE_INCOMPAT		2
 #define BCH_FEATURE_TYPE_MASK		0x03
 
+/* Feature set definition */
+/* Incompat feature set */
+#define BCH_FEATURE_INCOMPAT_LARGE_BUCKET	0x0001 /* 32bit bucket size */
+
 #define BCH_FEATURE_COMPAT_SUUP		0
 #define BCH_FEATURE_RO_COMPAT_SUUP	0
-#define BCH_FEATURE_INCOMPAT_SUUP	0
+#define BCH_FEATURE_INCOMPAT_SUUP	BCH_FEATURE_INCOMPAT_LARGE_BUCKET
 
 #define BCH_HAS_COMPAT_FEATURE(sb, mask) \
 		((sb)->feature_compat & (mask))
@@ -22,8 +26,6 @@
 #define BCH_HAS_INCOMPAT_FEATURE(sb, mask) \
 		((sb)->feature_incompat & (mask))
 
-/* Feature set definition */
-
 #define BCH_FEATURE_COMPAT_FUNCS(name, flagname) \
 static inline int bch_has_feature_##name(struct cache_sb *sb) \
 { \
@@ -75,4 +77,5 @@ static inline void bch_clear_feature_##name(struct cache_sb *sb) \
 		~BCH##_FEATURE_INCOMPAT_##flagname; \
 }
 
+BCH_FEATURE_INCOMPAT_FUNCS(large_bucket, LARGE_BUCKET);
 #endif
diff --git a/drivers/md/bcache/movinggc.c b/drivers/md/bcache/movinggc.c
index b7dd2d75f58c..5872d6470470 100644
--- a/drivers/md/bcache/movinggc.c
+++ b/drivers/md/bcache/movinggc.c
@@ -206,8 +206,8 @@ void bch_moving_gc(struct cache_set *c)
 	mutex_lock(&c->bucket_lock);
 
 	for_each_cache(ca, c, i) {
-		unsigned int sectors_to_move = 0;
-		unsigned int reserve_sectors = ca->sb.bucket_size *
+		unsigned long sectors_to_move = 0;
+		unsigned long reserve_sectors = ca->sb.bucket_size *
 			     fifo_used(&ca->free[RESERVE_MOVINGGC]);
 
 		ca->heap.used = 0;
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 172246ff5ec2..b7ef11da026c 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -60,6 +60,17 @@ struct workqueue_struct *bch_journal_wq;
 
 /* Superblock */
 
+static unsigned int get_bucket_size(struct cache_sb *sb, struct cache_sb_disk *s)
+{
+	unsigned int bucket_size = le16_to_cpu(s->bucket_size);
+
+	if (sb->version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES &&
+	     bch_has_feature_large_bucket(sb))
+		bucket_size |= le16_to_cpu(s->bucket_size_hi) << 16;
+
+	return bucket_size;
+}
+
 static const char *read_super_common(struct cache_sb *sb,  struct block_device *bdev,
 				     struct cache_sb_disk *s)
 {
@@ -68,7 +79,7 @@ static const char *read_super_common(struct cache_sb *sb,  struct block_device *
 
 	sb->first_bucket= le16_to_cpu(s->first_bucket);
 	sb->nbuckets	= le64_to_cpu(s->nbuckets);
-	sb->bucket_size	= le16_to_cpu(s->bucket_size);
+	sb->bucket_size	= get_bucket_size(sb, s);
 
 	sb->nr_in_set	= le16_to_cpu(s->nr_in_set);
 	sb->nr_this_dev	= le16_to_cpu(s->nr_this_dev);
@@ -210,12 +221,16 @@ static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
 			goto err;
 		break;
 	case BCACHE_SB_VERSION_CDEV_WITH_FEATURES:
-		err = read_super_common(sb, bdev, s);
-		if (err)
-			goto err;
+		/*
+		 * Feature bits are needed in read_super_common(),
+		 * convert them firstly.
+		 */
 		sb->feature_compat = le64_to_cpu(s->feature_compat);
 		sb->feature_incompat = le64_to_cpu(s->feature_incompat);
 		sb->feature_ro_compat = le64_to_cpu(s->feature_ro_compat);
+		err = read_super_common(sb, bdev, s);
+		if (err)
+			goto err;
 		break;
 	default:
 		err = "Unsupported superblock version";
diff --git a/include/uapi/linux/bcache.h b/include/uapi/linux/bcache.h
index 0ef984ea515a..52e8bcb33981 100644
--- a/include/uapi/linux/bcache.h
+++ b/include/uapi/linux/bcache.h
@@ -213,6 +213,7 @@ struct cache_sb_disk {
 		__le16		keys;
 	};
 	__le64			d[SB_JOURNAL_BUCKETS];	/* journal buckets */
+	__le16			bucket_size_hi;
 };
 
 /*
@@ -247,9 +248,9 @@ struct cache_sb {
 		__u64		nbuckets;	/* device size */
 
 		__u16		block_size;	/* sectors */
-		__u16		bucket_size;	/* sectors */
 		__u16		nr_in_set;
 		__u16		nr_this_dev;
+		__u32		bucket_size;	/* sectors */
 	};
 	struct {
 		/* Backing devices */
-- 
2.26.2


  parent reply	other threads:[~2020-07-25 12:03 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-25 12:00 [PATCH 00/25] bcache patches for Linux v5.9 Coly Li
2020-07-25 12:00 ` [PATCH 01/25] bcache: Fix typo in Kconfig name Coly Li
2020-07-25 12:00 ` [PATCH 02/25] bcache: allocate meta data pages as compound pages Coly Li
2020-07-25 12:00 ` [PATCH 03/25] bcache: journel: use for_each_clear_bit() to simplify the code Coly Li
2020-07-25 12:00 ` [PATCH 04/25] bcache: writeback: Remove unneeded variable i Coly Li
2020-07-25 12:00 ` [PATCH 05/25] bcache: movinggc: Use struct_size() helper in kzalloc() Coly Li
2020-07-25 12:00 ` [PATCH 06/25] bcache: Use struct_size() " Coly Li
2020-07-25 12:00 ` [PATCH 07/25] bcache: avoid nr_stripes overflow in bcache_device_init() Coly Li
2020-07-27 21:24   ` Sasha Levin
2020-07-25 12:00 ` [PATCH 08/25] bcache: fix overflow in offset_to_stripe() Coly Li
2020-07-27 21:24   ` Sasha Levin
2020-07-25 12:00 ` [PATCH 09/25] bcache: add read_super_common() to read major part of super block Coly Li
2020-07-25 12:00 ` [PATCH 10/25] bcache: add more accurate error information in read_super_common() Coly Li
2020-07-25 12:00 ` [PATCH 11/25] bcache: disassemble the big if() checks in bch_cache_set_alloc() Coly Li
2020-07-25 12:00 ` [PATCH 12/25] bcache: fix super block seq numbers comparision in register_cache_set() Coly Li
2020-07-25 12:00 ` [PATCH 13/25] bcache: increase super block version for cache device and backing device Coly Li
2020-07-25 12:00 ` [PATCH 14/25] bcache: move bucket related code into read_super_common() Coly Li
2020-07-25 12:00 ` [PATCH 15/25] bcache: struct cache_sb is only for in-memory super block now Coly Li
2020-07-25 12:00 ` [PATCH 16/25] bcache: introduce meta_bucket_pages() related helper routines Coly Li
2020-07-25 12:00 ` [PATCH 17/25] bcache: handle c->uuids properly for bucket size > 8MB Coly Li
2020-07-25 12:00 ` [PATCH 18/25] bcache: handle cache prio_buckets and disk_buckets " Coly Li
2020-07-25 12:00 ` [PATCH 19/25] bcache: handle cache set verify_ondisk " Coly Li
2020-07-25 12:00 ` [PATCH 20/25] bcache: handle btree node memory allocation " Coly Li
2020-07-25 12:00 ` Coly Li [this message]
2020-07-25 12:00 ` [PATCH 22/25] bcache: add sysfs file to display feature sets information of cache set Coly Li
2020-07-25 12:00 ` [PATCH 23/25] bcache: avoid extra memory allocation from mempool c->fill_iter Coly Li
2020-07-25 12:00 ` [PATCH 24/25] bcache: avoid extra memory consumption in struct bbio for large bucket size Coly Li
2020-07-25 12:00 ` [PATCH 25/25] bcache: fix bio_{start,end}_io_acct with proper device Coly Li
2020-07-26 15:07   ` Christoph Hellwig
2020-07-25 13:39 ` [PATCH 00/25] bcache patches for Linux v5.9 Jens Axboe
2020-07-28 12:14   ` Christoph Hellwig
2020-07-28 12:40     ` Coly Li
2020-07-28 12:41       ` Christoph Hellwig
2020-07-28 15:13       ` Jens Axboe

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