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List: linux-nilfs
Subject: [PATCH 3/7] nilfs2: do not call nilfs_mdt_bgl_lock() needlessly
From: Ryusuke Konishi <konishi.ryusuke () lab ! ntt ! co ! jp>
Date: 2015-09-19 10:32:58
Message-ID: 1442658782-3147-4-git-send-email-konishi.ryusuke () lab ! ntt ! co ! jp
[Download RAW message or body]
In the bitmap based allocator implementation, nilfs_mdt_bgl_lock()
helper is frequently used to get a spinlock protecting a target block
group. This reduces its usage and simplifies arguments of some
related functions by directly passing a pointer to the spinlock.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
---
fs/nilfs2/alloc.c | 84 ++++++++++++++++++++++++++-----------------------------
1 file changed, 40 insertions(+), 44 deletions(-)
diff --git a/fs/nilfs2/alloc.c b/fs/nilfs2/alloc.c
index afe98364..ff0d62c 100644
--- a/fs/nilfs2/alloc.c
+++ b/fs/nilfs2/alloc.c
@@ -133,38 +133,34 @@ nilfs_palloc_bitmap_blkoff(const struct inode *inode, unsigned long group)
/**
* nilfs_palloc_group_desc_nfrees - get the number of free entries in a group
- * @inode: inode of metadata file using this allocator
- * @group: group number
* @desc: pointer to descriptor structure for the group
+ * @lock: spin lock protecting @desc
*/
static unsigned long
-nilfs_palloc_group_desc_nfrees(struct inode *inode, unsigned long group,
- const struct nilfs_palloc_group_desc *desc)
+nilfs_palloc_group_desc_nfrees(const struct nilfs_palloc_group_desc *desc,
+ spinlock_t *lock)
{
unsigned long nfree;
- spin_lock(nilfs_mdt_bgl_lock(inode, group));
+ spin_lock(lock);
nfree = le32_to_cpu(desc->pg_nfrees);
- spin_unlock(nilfs_mdt_bgl_lock(inode, group));
+ spin_unlock(lock);
return nfree;
}
/**
* nilfs_palloc_group_desc_add_entries - adjust count of free entries
- * @inode: inode of metadata file using this allocator
- * @group: group number
* @desc: pointer to descriptor structure for the group
+ * @lock: spin lock protecting @desc
* @n: delta to be added
*/
static void
-nilfs_palloc_group_desc_add_entries(struct inode *inode,
- unsigned long group,
- struct nilfs_palloc_group_desc *desc,
- u32 n)
+nilfs_palloc_group_desc_add_entries(struct nilfs_palloc_group_desc *desc,
+ spinlock_t *lock, u32 n)
{
- spin_lock(nilfs_mdt_bgl_lock(inode, group));
+ spin_lock(lock);
le32_add_cpu(&desc->pg_nfrees, n);
- spin_unlock(nilfs_mdt_bgl_lock(inode, group));
+ spin_unlock(lock);
}
/**
@@ -332,17 +328,15 @@ void *nilfs_palloc_block_get_entry(const struct inode *inode, __u64 nr,
/**
* nilfs_palloc_find_available_slot - find available slot in a group
- * @inode: inode of metadata file using this allocator
- * @group: group number
- * @target: offset number of an entry in the group (start point)
* @bitmap: bitmap of the group
+ * @target: offset number of an entry in the group (start point)
* @bsize: size in bits
+ * @lock: spin lock protecting @bitmap
*/
-static int nilfs_palloc_find_available_slot(struct inode *inode,
- unsigned long group,
+static int nilfs_palloc_find_available_slot(unsigned char *bitmap,
unsigned long target,
- unsigned char *bitmap,
- int bsize)
+ int bsize,
+ spinlock_t *lock)
{
int curr, pos, end, i;
@@ -351,12 +345,11 @@ static int nilfs_palloc_find_available_slot(struct inode *inode,
if (end > bsize)
end = bsize;
pos = nilfs_find_next_zero_bit(bitmap, end, target);
- if (pos < end &&
- !nilfs_set_bit_atomic(
- nilfs_mdt_bgl_lock(inode, group), pos, bitmap))
+ if (pos < end && !nilfs_set_bit_atomic(lock, pos, bitmap))
return pos;
- } else
+ } else {
end = 0;
+ }
for (i = 0, curr = end;
i < bsize;
@@ -370,10 +363,8 @@ static int nilfs_palloc_find_available_slot(struct inode *inode,
if (end > bsize)
end = bsize;
pos = nilfs_find_next_zero_bit(bitmap, end, curr);
- if ((pos < end) &&
- !nilfs_set_bit_atomic(
- nilfs_mdt_bgl_lock(inode, group), pos,
- bitmap))
+ if (pos < end &&
+ !nilfs_set_bit_atomic(lock, pos, bitmap))
return pos;
}
}
@@ -477,6 +468,7 @@ int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
unsigned long group_offset, maxgroup_offset;
unsigned long n, entries_per_group, groups_per_desc_block;
unsigned long i, j;
+ spinlock_t *lock;
int pos, ret;
ngroups = nilfs_palloc_groups_count(inode);
@@ -501,8 +493,8 @@ int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
n = nilfs_palloc_rest_groups_in_desc_block(inode, group,
maxgroup);
for (j = 0; j < n; j++, desc++, group++) {
- if (nilfs_palloc_group_desc_nfrees(inode, group, desc)
- > 0) {
+ lock = nilfs_mdt_bgl_lock(inode, group);
+ if (nilfs_palloc_group_desc_nfrees(desc, lock) > 0) {
ret = nilfs_palloc_get_bitmap_block(
inode, group, 1, &bitmap_bh);
if (ret < 0)
@@ -510,12 +502,12 @@ int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
bitmap_kaddr = kmap(bitmap_bh->b_page);
bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
pos = nilfs_palloc_find_available_slot(
- inode, group, group_offset, bitmap,
- entries_per_group);
+ bitmap, group_offset,
+ entries_per_group, lock);
if (pos >= 0) {
/* found a free entry */
nilfs_palloc_group_desc_add_entries(
- inode, group, desc, -1);
+ desc, lock, -1);
req->pr_entry_nr =
entries_per_group * group + pos;
kunmap(desc_bh->b_page);
@@ -573,6 +565,7 @@ void nilfs_palloc_commit_free_entry(struct inode *inode,
unsigned long group, group_offset;
unsigned char *bitmap;
void *desc_kaddr, *bitmap_kaddr;
+ spinlock_t *lock;
group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
desc_kaddr = kmap(req->pr_desc_bh->b_page);
@@ -580,15 +573,15 @@ void nilfs_palloc_commit_free_entry(struct inode *inode,
req->pr_desc_bh, desc_kaddr);
bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
bitmap = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
+ lock = nilfs_mdt_bgl_lock(inode, group);
- if (!nilfs_clear_bit_atomic(nilfs_mdt_bgl_lock(inode, group),
- group_offset, bitmap))
+ if (!nilfs_clear_bit_atomic(lock, group_offset, bitmap))
nilfs_warning(inode->i_sb, __func__,
"entry number %llu already freed: ino=%lu\n",
(unsigned long long)req->pr_entry_nr,
(unsigned long)inode->i_ino);
else
- nilfs_palloc_group_desc_add_entries(inode, group, desc, 1);
+ nilfs_palloc_group_desc_add_entries(desc, lock, 1);
kunmap(req->pr_bitmap_bh->b_page);
kunmap(req->pr_desc_bh->b_page);
@@ -613,6 +606,7 @@ void nilfs_palloc_abort_alloc_entry(struct inode *inode,
void *desc_kaddr, *bitmap_kaddr;
unsigned char *bitmap;
unsigned long group, group_offset;
+ spinlock_t *lock;
group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
desc_kaddr = kmap(req->pr_desc_bh->b_page);
@@ -620,14 +614,15 @@ void nilfs_palloc_abort_alloc_entry(struct inode *inode,
req->pr_desc_bh, desc_kaddr);
bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
bitmap = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
- if (!nilfs_clear_bit_atomic(nilfs_mdt_bgl_lock(inode, group),
- group_offset, bitmap))
+ lock = nilfs_mdt_bgl_lock(inode, group);
+
+ if (!nilfs_clear_bit_atomic(lock, group_offset, bitmap))
nilfs_warning(inode->i_sb, __func__,
"entry number %llu already freed: ino=%lu\n",
(unsigned long long)req->pr_entry_nr,
(unsigned long)inode->i_ino);
else
- nilfs_palloc_group_desc_add_entries(inode, group, desc, 1);
+ nilfs_palloc_group_desc_add_entries(desc, lock, 1);
kunmap(req->pr_bitmap_bh->b_page);
kunmap(req->pr_desc_bh->b_page);
@@ -712,6 +707,7 @@ int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
unsigned char *bitmap;
void *desc_kaddr, *bitmap_kaddr;
unsigned long group, group_offset;
+ spinlock_t *lock;
int i, j, n, ret;
for (i = 0; i < nitems; i = j) {
@@ -730,14 +726,14 @@ int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
inode, group, desc_bh, desc_kaddr);
bitmap_kaddr = kmap(bitmap_bh->b_page);
bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
+ lock = nilfs_mdt_bgl_lock(inode, group);
for (j = i, n = 0;
(j < nitems) && nilfs_palloc_group_is_in(inode, group,
entry_nrs[j]);
j++) {
nilfs_palloc_group(inode, entry_nrs[j], &group_offset);
- if (!nilfs_clear_bit_atomic(
- nilfs_mdt_bgl_lock(inode, group),
- group_offset, bitmap)) {
+ if (!nilfs_clear_bit_atomic(lock, group_offset,
+ bitmap)) {
nilfs_warning(inode->i_sb, __func__,
"entry number %llu already freed: ino=%lu\n",
(unsigned long long)entry_nrs[j],
@@ -746,7 +742,7 @@ int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
n++;
}
}
- nilfs_palloc_group_desc_add_entries(inode, group, desc, n);
+ nilfs_palloc_group_desc_add_entries(desc, lock, n);
kunmap(bitmap_bh->b_page);
kunmap(desc_bh->b_page);
--
1.8.3.1
--
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