ext4: don't use ext4_allocation_contexts for tracing

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>

1 files changed, 29 insertions, 22 deletions

diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
index fbdfa3a6bbd8..b5f4938d612d 100644
--- a/include/trace/events/ext4.h
+++ b/include/trace/events/ext4.h
@@ -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                     )
@@ -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;
         ),
@@ -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                     )
@@ -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,