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author | John Reiser <jreiser@bitwagon.com> | 2009-07-27 11:23:50 -0700 |
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committer | Steven Rostedt <rostedt@goodmis.org> | 2009-09-12 21:57:29 -0400 |
commit | 4b3b4c5e64ce26612646867ee354373620063534 (patch) | |
tree | 048ff75a616c83c5bd64372f4140d53c9f79f169 /include/linux/kmalloc_sizes.h | |
parent | b5130b1e7d3717d03ab1916b198bf0d49fa0a619 (diff) |
ftrace: __start_mcount_loc should be .init.rodata
__start_mcount_loc[] is unused after init, yet occupies RAM forever
as part of .rodata. 152kiB is typical on a 64-bit architecture. Instead,
__start_mcount_loc should be in the interval [__init_begin, __init_end)
so that the space is reclaimed after init.
__start_mcount_loc[] is generated during the load portion
of kernel build, and is used only by ftrace_init(). ftrace_init is declared
'__init' and is in .init.text, which is freed after init.
__start_mcount_loc is placed into .rodata by a call to MCOUNT_REC inside
the RO_DATA macro of include/asm-generic/vmlinux.lds.h. The array *is*
read-only, but more importantly it is not used after init. So the call to
MCOUNT_REC should be moved from RO_DATA to INIT_DATA.
This patch has been tested on x86_64 with CONFIG_DEBUG_PAGEALLOC=y
which verifies that the address range never is accessed after init.
Signed-off-by: John Reiser <jreiser@BitWagon.com>
LKML-Reference: <4A6DF0B6.7080402@bitwagon.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'include/linux/kmalloc_sizes.h')
0 files changed, 0 insertions, 0 deletions