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authorIngo Molnar <mingo@elte.hu>2008-07-17 17:40:48 +0200
committerIngo Molnar <mingo@elte.hu>2008-07-17 17:40:48 +0200
commit2464a609ded094204a3aed24823745ec58e3c879 (patch)
tree54080daf81746787dbd11160752e04b9652b8728 /lib/Makefile
parentc349e0a01c3e0f70913db6a5bb61ab204e0602de (diff)
downloadlinux-2464a609ded094204a3aed24823745ec58e3c879.tar.bz2
ftrace: do not trace library functions
make function tracing more robust: do not trace library functions. We've already got a sizable list of exceptions: ifdef CONFIG_FTRACE # Do not profile string.o, since it may be used in early boot or vdso CFLAGS_REMOVE_string.o = -pg # Also do not profile any debug utilities CFLAGS_REMOVE_spinlock_debug.o = -pg CFLAGS_REMOVE_list_debug.o = -pg CFLAGS_REMOVE_debugobjects.o = -pg CFLAGS_REMOVE_find_next_bit.o = -pg CFLAGS_REMOVE_cpumask.o = -pg CFLAGS_REMOVE_bitmap.o = -pg endif ... and the pattern has been that random library functionality showed up in ftrace's critical path (outside of its recursion check), causing hard to debug lockups. So be a bit defensive about it and exclude all lib/*.o functions by default. It's not that they are overly interesting for tracing purposes anyway. Specific ones can still be traced, in an opt-in manner. Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'lib/Makefile')
-rw-r--r--lib/Makefile17
1 files changed, 5 insertions, 12 deletions
diff --git a/lib/Makefile b/lib/Makefile
index d90d31102e05..818c4d455518 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -2,24 +2,17 @@
# Makefile for some libs needed in the kernel.
#
+ifdef CONFIG_FTRACE
+ORIG_CFLAGS := $(KBUILD_CFLAGS)
+KBUILD_CFLAGS = $(subst -pg,,$(ORIG_CFLAGS))
+endif
+
lib-y := ctype.o string.o vsprintf.o cmdline.o \
rbtree.o radix-tree.o dump_stack.o \
idr.o int_sqrt.o extable.o prio_tree.o \
sha1.o irq_regs.o reciprocal_div.o argv_split.o \
proportions.o prio_heap.o ratelimit.o
-ifdef CONFIG_FTRACE
-# Do not profile string.o, since it may be used in early boot or vdso
-CFLAGS_REMOVE_string.o = -pg
-# Also do not profile any debug utilities
-CFLAGS_REMOVE_spinlock_debug.o = -pg
-CFLAGS_REMOVE_list_debug.o = -pg
-CFLAGS_REMOVE_debugobjects.o = -pg
-CFLAGS_REMOVE_find_next_bit.o = -pg
-CFLAGS_REMOVE_cpumask.o = -pg
-CFLAGS_REMOVE_bitmap.o = -pg
-endif
-
lib-$(CONFIG_MMU) += ioremap.o
lib-$(CONFIG_SMP) += cpumask.o