From bfe26f0c06cb20438096ea69fa2c9842ffbc9cce Mon Sep 17 00:00:00 2001
From: nikita <nikita>
Date: Tue, 5 Dec 2006 22:04:59 +0000
Subject: [PATCH] add temporary kernel debugging to track where
 __find_get_block() and try_to_wake_up() are called from. Spams console,
 beware.

---
 lustre/kernel_patches/patches/tmp-debug.patch | 64 +++++++++++++++++++++++++++
 lustre/kernel_patches/series/2.6-rhel4.series |  1 +
 2 files changed, 65 insertions(+)
 create mode 100644 lustre/kernel_patches/patches/tmp-debug.patch

diff --git a/lustre/kernel_patches/patches/tmp-debug.patch b/lustre/kernel_patches/patches/tmp-debug.patch
new file mode 100644
index 0000000..feed65b
--- /dev/null
+++ b/lustre/kernel_patches/patches/tmp-debug.patch
@@ -0,0 +1,64 @@
+Index: linux/fs/buffer.c
+===================================================================
+--- linux.orig/fs/buffer.c
++++ linux/fs/buffer.c
+@@ -1528,6 +1528,9 @@ lookup_bh_lru(struct block_device *bdev,
+ 	return ret;
+ }
+ 
++int __find_get_block_trace = 0;
++EXPORT_SYMBOL(__find_get_block_trace);
++
+ /*
+  * Perform a pagecache lookup for the matching buffer.  If it's there, refresh
+  * it in the LRU and mark it as accessed.  If it is not present then return
+@@ -1538,6 +1541,17 @@ __find_get_block(struct block_device *bd
+ {
+ 	struct buffer_head *bh = lookup_bh_lru(bdev, block, size);
+ 
++	if (__find_get_block_trace != 0) {
++		static unsigned long last_dump;
++
++		if (time_after(jiffies,
++			       last_dump + __find_get_block_trace * HZ)) {
++			last_dump = jiffies;
++			printk("%s@%lu\n", __FUNCTION__, last_dump);
++			dump_stack();
++		}
++	}
++
+ 	if (bh == NULL) {
+ 		bh = __find_get_block_slow(bdev, block, size);
+ 		if (bh)
+Index: linux/kernel/sched.c
+===================================================================
+--- linux.orig/kernel/sched.c
++++ linux/kernel/sched.c
+@@ -1106,6 +1106,9 @@ static inline int wake_idle(int cpu, tas
+ }
+ #endif
+ 
++int try_to_wake_up_trace = 0;
++EXPORT_SYMBOL(try_to_wake_up_trace);
++
+ /***
+  * try_to_wake_up - wake up a thread
+  * @p: the to-be-woken-up thread
+@@ -1132,6 +1135,17 @@ static int try_to_wake_up(task_t * p, un
+ 	int new_cpu;
+ #endif
+ 
++	if (try_to_wake_up_trace != 0) {
++		static unsigned long last_dump;
++
++		if (time_after(jiffies,
++			       last_dump + try_to_wake_up_trace * HZ)) {
++			last_dump = jiffies;
++			printk("%s@%lu\n", __FUNCTION__, last_dump);
++			dump_stack();
++		}
++	}
++
+ 	rq = task_rq_lock(p, &flags);
+ 	schedstat_inc(rq, ttwu_cnt);
+ 	old_state = p->state;
diff --git a/lustre/kernel_patches/series/2.6-rhel4.series b/lustre/kernel_patches/series/2.6-rhel4.series
index 1704b18..ca9614c 100644
--- a/lustre/kernel_patches/series/2.6-rhel4.series
+++ b/lustre/kernel_patches/series/2.6-rhel4.series
@@ -38,3 +38,4 @@ export-nr_free_buffer_pages.patch
 __find_get_block_slow-scale.patch 
 debugging-fields-in-current.patch 
 increase-BH_LRU_SIZE.patch 
+tmp-debug.patch 
-- 
1.8.3.1