[XFS] Keep stack usage down for 4k stacks by using noinline.

gcc-4.1 and more recent aggressively inline static functions which
increases XFS stack usage by ~15% in critical paths. Prevent this from
occurring by adding noinline to the STATIC definition.

Also uninline some functions that are too large to be inlined and were
causing problems with CONFIG_FORCED_INLINING=y.

Finally, clean up all the different users of inline, __inline and
__inline__ and put them under one STATIC_INLINE macro. For debug kernels
the STATIC_INLINE macro uninlines those functions.

SGI-PV: 957159
SGI-Modid: xfs-linux-melb:xfs-kern:27585a

Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: David Chatterton <chatz@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>

fs/xfs/support/debug.h

@@ -38,13 +38,37 @@ extern void assfail(char *expr, char *f, int l);
 
 #ifndef DEBUG
 # define ASSERT(expr)	((void)0)
-#else
-# define ASSERT(expr)	ASSERT_ALWAYS(expr)
-extern unsigned long random(void);
-#endif
 
 #ifndef STATIC
-# define STATIC static
+# define STATIC static noinline
 #endif
 
+#ifndef STATIC_INLINE
+# define STATIC_INLINE static inline
+#endif
+
+#else /* DEBUG */
+
+# define ASSERT(expr)	ASSERT_ALWAYS(expr)
+extern unsigned long random(void);
+
+#ifndef STATIC
+# define STATIC noinline
+#endif
+
+/*
+ * We stop inlining of inline functions in debug mode.
+ * Unfortunately, this means static inline in header files
+ * get multiple definitions, so they need to remain static.
+ * This then gives tonnes of warnings about unused but defined
+ * functions, so we need to add the unused attribute to prevent
+ * these spurious warnings.
+ */
+#ifndef STATIC_INLINE
+# define STATIC_INLINE static __attribute__ ((unused)) noinline
+#endif
+
+#endif /* DEBUG */
+
+
 #endif  /* __XFS_SUPPORT_DEBUG_H__ */