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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-08-05 12:59:05 -0600 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2010-08-05 12:59:06 +0930 |
| commit | 44032e631691adf1f406843d5e54deb795973ff7 (patch) | |
| tree | e9cb4f72974386a2b174bf6e21f41be9aece7a10 /kernel | |
| parent | 22e268ebecc549f1b1907f114cb44d6044bdee3c (diff) | |
| download | lwn-44032e631691adf1f406843d5e54deb795973ff7.tar.gz lwn-44032e631691adf1f406843d5e54deb795973ff7.zip | |
module: reduce stack usage for each_symbol()
And now that I'm looking at that call-chain (to see if it would make sense
to use some other more specific lock - doesn't look like it: all the
readers are using RCU and this is the only writer), I also give you this
trivial one-liner. It changes each_symbol() to not put that constant array
on the stack, resulting in changing
movq $C.388.31095, %rsi #, tmp85
subq $376, %rsp #,
movq %rdi, %rbx # fn, fn
leaq -208(%rbp), %rdi #, tmp84
movq %rbx, %rdx # fn,
rep movsl
xorl %esi, %esi #
leaq -208(%rbp), %rdi #, tmp87
movq %r12, %rcx # data,
call each_symbol_in_section.clone.0 #
into
xorl %esi, %esi #
subq $216, %rsp #,
movq %rdi, %rbx # fn, fn
movq $arr.31078, %rdi #,
call each_symbol_in_section.clone.0 #
which is not so much about being obviously shorter and simpler because we
don't unnecessarily copy that constant array around onto the stack, but
also about having a much smaller stack footprint (376 vs 216 bytes - see
the update of 'rsp').
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/module.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/module.c b/kernel/module.c index b536db804ca0..79545bda358a 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -227,7 +227,7 @@ bool each_symbol(bool (*fn)(const struct symsearch *arr, struct module *owner, unsigned int symnum, void *data), void *data) { struct module *mod; - const struct symsearch arr[] = { + static const struct symsearch arr[] = { { __start___ksymtab, __stop___ksymtab, __start___kcrctab, NOT_GPL_ONLY, false }, { __start___ksymtab_gpl, __stop___ksymtab_gpl, |