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ext4: don't use ext4_allocation_contexts for tracing
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Many tracepoints were populating an ext4_allocation_context
to pass in, but this requires a slab allocation even when
tracepoints are off.  In fact, 4 of 5 of these allocations
were only for tracing.  In addition, we were only using a
small fraction of the 144 bytes of this structure for this
purpose.

We can do away with all these alloc/frees of the ac and
simply pass in the bits we care about, instead.

I tested this by turning on tracing and running through
xfstests on x86_64.  I did not actually do anything with
the trace output, however.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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Eric Sandeen authored and Theodore Ts'o committed Oct 28, 2010
1 parent 4d54761 commit 3e1e5f5
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Showing 2 changed files with 41 additions and 91 deletions.
81 changes: 12 additions & 69 deletions fs/ext4/mballoc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3591,8 +3591,7 @@ static int ext4_mb_new_preallocation(struct ext4_allocation_context *ac)
*/
static noinline_for_stack int
ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
struct ext4_prealloc_space *pa,
struct ext4_allocation_context *ac)
struct ext4_prealloc_space *pa)
{
struct super_block *sb = e4b->bd_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
Expand All @@ -3610,11 +3609,6 @@ ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
end = bit + pa->pa_len;

if (ac) {
ac->ac_sb = sb;
ac->ac_inode = pa->pa_inode;
}

while (bit < end) {
bit = mb_find_next_zero_bit(bitmap_bh->b_data, end, bit);
if (bit >= end)
Expand All @@ -3625,16 +3619,9 @@ ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
(unsigned) next - bit, (unsigned) group);
free += next - bit;

if (ac) {
ac->ac_b_ex.fe_group = group;
ac->ac_b_ex.fe_start = bit;
ac->ac_b_ex.fe_len = next - bit;
ac->ac_b_ex.fe_logical = 0;
trace_ext4_mballoc_discard(ac);
}

trace_ext4_mb_release_inode_pa(sb, ac, pa, grp_blk_start + bit,
next - bit);
trace_ext4_mballoc_discard(sb, NULL, group, bit, next - bit);
trace_ext4_mb_release_inode_pa(sb, pa->pa_inode, pa,
grp_blk_start + bit, next - bit);
mb_free_blocks(pa->pa_inode, e4b, bit, next - bit);
bit = next + 1;
}
Expand All @@ -3657,29 +3644,19 @@ ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,

static noinline_for_stack int
ext4_mb_release_group_pa(struct ext4_buddy *e4b,
struct ext4_prealloc_space *pa,
struct ext4_allocation_context *ac)
struct ext4_prealloc_space *pa)
{
struct super_block *sb = e4b->bd_sb;
ext4_group_t group;
ext4_grpblk_t bit;

trace_ext4_mb_release_group_pa(sb, ac, pa);
trace_ext4_mb_release_group_pa(sb, pa);
BUG_ON(pa->pa_deleted == 0);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
mb_free_blocks(pa->pa_inode, e4b, bit, pa->pa_len);
atomic_add(pa->pa_len, &EXT4_SB(sb)->s_mb_discarded);

if (ac) {
ac->ac_sb = sb;
ac->ac_inode = NULL;
ac->ac_b_ex.fe_group = group;
ac->ac_b_ex.fe_start = bit;
ac->ac_b_ex.fe_len = pa->pa_len;
ac->ac_b_ex.fe_logical = 0;
trace_ext4_mballoc_discard(ac);
}
trace_ext4_mballoc_discard(sb, NULL, group, bit, pa->pa_len);

return 0;
}
Expand All @@ -3700,7 +3677,6 @@ ext4_mb_discard_group_preallocations(struct super_block *sb,
struct ext4_group_info *grp = ext4_get_group_info(sb, group);
struct buffer_head *bitmap_bh = NULL;
struct ext4_prealloc_space *pa, *tmp;
struct ext4_allocation_context *ac;
struct list_head list;
struct ext4_buddy e4b;
int err;
Expand Down Expand Up @@ -3729,9 +3705,6 @@ ext4_mb_discard_group_preallocations(struct super_block *sb,
needed = EXT4_BLOCKS_PER_GROUP(sb) + 1;

INIT_LIST_HEAD(&list);
ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
if (ac)
ac->ac_sb = sb;
repeat:
ext4_lock_group(sb, group);
list_for_each_entry_safe(pa, tmp,
Expand Down Expand Up @@ -3786,18 +3759,16 @@ ext4_mb_discard_group_preallocations(struct super_block *sb,
spin_unlock(pa->pa_obj_lock);

if (pa->pa_type == MB_GROUP_PA)
ext4_mb_release_group_pa(&e4b, pa, ac);
ext4_mb_release_group_pa(&e4b, pa);
else
ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa, ac);
ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);

list_del(&pa->u.pa_tmp_list);
call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
}

out:
ext4_unlock_group(sb, group);
if (ac)
kmem_cache_free(ext4_ac_cachep, ac);
ext4_mb_unload_buddy(&e4b);
put_bh(bitmap_bh);
return free;
Expand All @@ -3818,7 +3789,6 @@ void ext4_discard_preallocations(struct inode *inode)
struct super_block *sb = inode->i_sb;
struct buffer_head *bitmap_bh = NULL;
struct ext4_prealloc_space *pa, *tmp;
struct ext4_allocation_context *ac;
ext4_group_t group = 0;
struct list_head list;
struct ext4_buddy e4b;
Expand All @@ -3834,11 +3804,6 @@ void ext4_discard_preallocations(struct inode *inode)

INIT_LIST_HEAD(&list);

ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
if (ac) {
ac->ac_sb = sb;
ac->ac_inode = inode;
}
repeat:
/* first, collect all pa's in the inode */
spin_lock(&ei->i_prealloc_lock);
Expand Down Expand Up @@ -3908,7 +3873,7 @@ void ext4_discard_preallocations(struct inode *inode)

ext4_lock_group(sb, group);
list_del(&pa->pa_group_list);
ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa, ac);
ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
ext4_unlock_group(sb, group);

ext4_mb_unload_buddy(&e4b);
Expand All @@ -3917,8 +3882,6 @@ void ext4_discard_preallocations(struct inode *inode)
list_del(&pa->u.pa_tmp_list);
call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
}
if (ac)
kmem_cache_free(ext4_ac_cachep, ac);
}

/*
Expand Down Expand Up @@ -4116,14 +4079,10 @@ ext4_mb_discard_lg_preallocations(struct super_block *sb,
struct ext4_buddy e4b;
struct list_head discard_list;
struct ext4_prealloc_space *pa, *tmp;
struct ext4_allocation_context *ac;

mb_debug(1, "discard locality group preallocation\n");

INIT_LIST_HEAD(&discard_list);
ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
if (ac)
ac->ac_sb = sb;

spin_lock(&lg->lg_prealloc_lock);
list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[order],
Expand Down Expand Up @@ -4175,15 +4134,13 @@ ext4_mb_discard_lg_preallocations(struct super_block *sb,
}
ext4_lock_group(sb, group);
list_del(&pa->pa_group_list);
ext4_mb_release_group_pa(&e4b, pa, ac);
ext4_mb_release_group_pa(&e4b, pa);
ext4_unlock_group(sb, group);

ext4_mb_unload_buddy(&e4b);
list_del(&pa->u.pa_tmp_list);
call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
}
if (ac)
kmem_cache_free(ext4_ac_cachep, ac);
}

/*
Expand Down Expand Up @@ -4547,7 +4504,6 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
{
struct buffer_head *bitmap_bh = NULL;
struct super_block *sb = inode->i_sb;
struct ext4_allocation_context *ac = NULL;
struct ext4_group_desc *gdp;
unsigned long freed = 0;
unsigned int overflow;
Expand Down Expand Up @@ -4602,12 +4558,6 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
if (!ext4_should_writeback_data(inode))
flags |= EXT4_FREE_BLOCKS_METADATA;

ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
if (ac) {
ac->ac_inode = inode;
ac->ac_sb = sb;
}

do_more:
overflow = 0;
ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
Expand Down Expand Up @@ -4665,12 +4615,7 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
BUG_ON(!mb_test_bit(bit + i, bitmap_bh->b_data));
}
#endif
if (ac) {
ac->ac_b_ex.fe_group = block_group;
ac->ac_b_ex.fe_start = bit;
ac->ac_b_ex.fe_len = count;
trace_ext4_mballoc_free(ac);
}
trace_ext4_mballoc_free(sb, inode, block_group, bit, count);

err = ext4_mb_load_buddy(sb, block_group, &e4b);
if (err)
Expand Down Expand Up @@ -4741,7 +4686,5 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
dquot_free_block(inode, freed);
brelse(bitmap_bh);
ext4_std_error(sb, err);
if (ac)
kmem_cache_free(ext4_ac_cachep, ac);
return;
}
51 changes: 29 additions & 22 deletions include/trace/events/ext4.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -396,11 +396,11 @@ DEFINE_EVENT(ext4__mb_new_pa, ext4_mb_new_group_pa,

TRACE_EVENT(ext4_mb_release_inode_pa,
TP_PROTO(struct super_block *sb,
struct ext4_allocation_context *ac,
struct inode *inode,
struct ext4_prealloc_space *pa,
unsigned long long block, unsigned int count),

TP_ARGS(sb, ac, pa, block, count),
TP_ARGS(sb, inode, pa, block, count),

TP_STRUCT__entry(
__field( dev_t, dev )
Expand All @@ -412,8 +412,7 @@ TRACE_EVENT(ext4_mb_release_inode_pa,

TP_fast_assign(
__entry->dev = sb->s_dev;
__entry->ino = (ac && ac->ac_inode) ?
ac->ac_inode->i_ino : 0;
__entry->ino = inode->i_ino;
__entry->block = block;
__entry->count = count;
),
Expand All @@ -425,10 +424,9 @@ TRACE_EVENT(ext4_mb_release_inode_pa,

TRACE_EVENT(ext4_mb_release_group_pa,
TP_PROTO(struct super_block *sb,
struct ext4_allocation_context *ac,
struct ext4_prealloc_space *pa),

TP_ARGS(sb, ac, pa),
TP_ARGS(sb, pa),

TP_STRUCT__entry(
__field( dev_t, dev )
Expand Down Expand Up @@ -779,47 +777,56 @@ TRACE_EVENT(ext4_mballoc_prealloc,
);

DECLARE_EVENT_CLASS(ext4__mballoc,
TP_PROTO(struct ext4_allocation_context *ac),
TP_PROTO(struct super_block *sb,
struct inode *inode,
ext4_group_t group,
ext4_grpblk_t start,
ext4_grpblk_t len),

TP_ARGS(ac),
TP_ARGS(sb, inode, group, start, len),

TP_STRUCT__entry(
__field( dev_t, dev )
__field( ino_t, ino )
__field( __u32, result_logical )
__field( int, result_start )
__field( __u32, result_group )
__field( int, result_len )
),

TP_fast_assign(
__entry->dev = ac->ac_sb->s_dev;
__entry->ino = ac->ac_inode ?
ac->ac_inode->i_ino : 0;
__entry->result_logical = ac->ac_b_ex.fe_logical;
__entry->result_start = ac->ac_b_ex.fe_start;
__entry->result_group = ac->ac_b_ex.fe_group;
__entry->result_len = ac->ac_b_ex.fe_len;
__entry->dev = sb->s_dev;
__entry->ino = inode ? inode->i_ino : 0;
__entry->result_start = start;
__entry->result_group = group;
__entry->result_len = len;
),

TP_printk("dev %s inode %lu extent %u/%d/%u@%u ",
TP_printk("dev %s inode %lu extent %u/%d/%u ",
jbd2_dev_to_name(__entry->dev), (unsigned long) __entry->ino,
__entry->result_group, __entry->result_start,
__entry->result_len, __entry->result_logical)
__entry->result_len)
);

DEFINE_EVENT(ext4__mballoc, ext4_mballoc_discard,

TP_PROTO(struct ext4_allocation_context *ac),
TP_PROTO(struct super_block *sb,
struct inode *inode,
ext4_group_t group,
ext4_grpblk_t start,
ext4_grpblk_t len),

TP_ARGS(ac)
TP_ARGS(sb, inode, group, start, len)
);

DEFINE_EVENT(ext4__mballoc, ext4_mballoc_free,

TP_PROTO(struct ext4_allocation_context *ac),
TP_PROTO(struct super_block *sb,
struct inode *inode,
ext4_group_t group,
ext4_grpblk_t start,
ext4_grpblk_t len),

TP_ARGS(ac)
TP_ARGS(sb, inode, group, start, len)
);

TRACE_EVENT(ext4_forget,
Expand Down

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