[PATCH 5/6] f2fs: add spin_lock to cover radix operations in IO tracer

[Jaegeuk Kim <jaegeuk@kernel.org>]

This patch adds spin_lock to cover radix tree operations in IO tracer.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/super.c |  2 ++
 fs/f2fs/trace.c | 18 +++++++++++++++---
 fs/f2fs/trace.h |  2 ++
 3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 0ae6a2f..e6f035c 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1222,6 +1222,8 @@ static int __init init_f2fs_fs(void)
 {
 	int err;
 
+	f2fs_build_trace_ios();
+
 	err = init_inodecache();
 	if (err)
 		goto fail;
diff --git a/fs/f2fs/trace.c b/fs/f2fs/trace.c
index 19f5216..92fa38a 100644
--- a/fs/f2fs/trace.c
+++ b/fs/f2fs/trace.c
@@ -15,7 +15,8 @@
 #include "f2fs.h"
 #include "trace.h"
 
-RADIX_TREE(pids, GFP_NOIO);
+RADIX_TREE(pids, GFP_ATOMIC);
+spinlock_t pids_lock;
 struct last_io_info last_io;
 
 static inline void __print_last_io(void)
@@ -58,9 +59,13 @@ void f2fs_trace_pid(struct page *page)
 
 	page->private = pid;
 
+	if (radix_tree_preload(GFP_NOFS))
+		return;
+
+	spin_lock(&pids_lock);
 	p = radix_tree_lookup(&pids, pid);
 	if (p == current)
-		return;
+		goto out;
 	if (p)
 		radix_tree_delete(&pids, pid);
 
@@ -69,7 +74,9 @@ void f2fs_trace_pid(struct page *page)
 	trace_printk("%3x:%3x %4x %-16s\n",
 			MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev),
 			pid, current->comm);
-
+out:
+	spin_unlock(&pids_lock);
+	radix_tree_preload_end();
 }
 
 void f2fs_trace_ios(struct page *page, struct f2fs_io_info *fio, int flush)
@@ -108,3 +115,8 @@ void f2fs_trace_ios(struct page *page, struct f2fs_io_info *fio, int flush)
 	last_io.len = 1;
 	return;
 }
+
+void f2fs_build_trace_ios(void)
+{
+	spin_lock_init(&pids_lock);
+}
diff --git a/fs/f2fs/trace.h b/fs/f2fs/trace.h
index aa6663b..eb39fa0 100644
--- a/fs/f2fs/trace.h
+++ b/fs/f2fs/trace.h
@@ -34,9 +34,11 @@ struct last_io_info {
 
 extern void f2fs_trace_pid(struct page *);
 extern void f2fs_trace_ios(struct page *, struct f2fs_io_info *, int);
+extern void f2fs_build_trace_ios(void);
 #else
 #define f2fs_trace_pid(p)
 #define f2fs_trace_ios(p, i, n)
+#define f2fs_build_trace_ios()
 
 #endif
 #endif /* __F2FS_TRACE_H__ */
-- 
2.1.1


------------------------------------------------------------------------------
Dive into the World of Parallel Programming! The Go Parallel Website,
sponsored by Intel and developed in partnership with Slashdot Media, is your
hub for all things parallel software development, from weekly thought
leadership blogs to news, videos, case studies, tutorials and more. Take a
look and join the conversation now. http://goparallel.sourceforge.net