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| author | Feng Tang <feng.tang@intel.com> | 2021-05-06 15:34:59 +0800 |
|---|---|---|
| committer | Masahiro Yamada <masahiroy@kernel.org> | 2021-05-24 12:06:50 +0900 |
| commit | cf536e185869d4815d506e777bcca6edd9966a6e (patch) | |
| tree | d54d136af71ec07adca5db16d959540ffbf071b1 /Makefile | |
| parent | c4681547bcce777daf576925a966ffa824edd09d (diff) | |
| download | lwn-cf536e185869d4815d506e777bcca6edd9966a6e.tar.gz lwn-cf536e185869d4815d506e777bcca6edd9966a6e.zip | |
Makefile: extend 32B aligned debug option to 64B aligned
Commit 09c60546f04f ("./Makefile: add debug option to enable
function aligned on 32 bytes") was introduced to help debugging
strange kernel performance changes caused by code alignment
change.
Recently we found 2 similar cases [1][2] caused by code-alignment
changes, which can only be identified by forcing 64 bytes aligned
for all functions.
Originally, 32 bytes was used mainly for not wasting too much
text space, but this option is only for debug anyway where text
space is not a big concern. So extend the alignment to 64 bytes
to cover more similar cases.
[1].https://lore.kernel.org/lkml/20210427090013.GG32408@xsang-OptiPlex-9020/
[2].https://lore.kernel.org/lkml/20210420030837.GB31773@xsang-OptiPlex-9020/
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'Makefile')
| -rw-r--r-- | Makefile | 4 |
1 files changed, 2 insertions, 2 deletions
@@ -953,8 +953,8 @@ KBUILD_CFLAGS += $(CC_FLAGS_CFI) export CC_FLAGS_CFI endif -ifdef CONFIG_DEBUG_FORCE_FUNCTION_ALIGN_32B -KBUILD_CFLAGS += -falign-functions=32 +ifdef CONFIG_DEBUG_FORCE_FUNCTION_ALIGN_64B +KBUILD_CFLAGS += -falign-functions=64 endif # arch Makefile may override CC so keep this after arch Makefile is included |