Messages in this thread | | | From | Nick Desaulniers <> | Date | Mon, 6 Dec 2021 11:43:47 -0800 | Subject | Re: [PATCH] numa: mark __next_node() as __always_inline to fix section mismatch |
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On Mon, Dec 6, 2021 at 8:19 AM Alexander Lobakin <alexandr.lobakin@intel.com> wrote: > > Clang (13) uninlines __next_node() which emits the following warning > due to that this function is used in init code (amd_numa_init(), > sched_init_numa() etc.): > > WARNING: modpost: vmlinux.o(.text+0x927ee): Section mismatch > in reference from the function __next_node() to the variable > .init.data:numa_nodes_parsed > The function __next_node() references > the variable __initdata numa_nodes_parsed. > This is often because __next_node lacks a __initdata > annotation or the annotation of numa_nodes_parsed is wrong. > > Mark __next_node() as __always_inline() so it won't get uninlined. > bloat-o-meter over x86_64 binaries says this: > > scripts/bloat-o-meter -c vmlinux.baseline vmlinux > add/remove: 1/1 grow/shrink: 2/7 up/down: 446/-2166 (-1720) > Function old new delta > apply_wqattrs_cleanup - 410 +410 > amd_numa_init 814 842 +28 > sched_init_numa 1338 1346 +8 > find_next_bit 38 19 -19 > __next_node 45 - -45 > apply_wqattrs_prepare 1069 799 -270 > wq_nice_store 688 414 -274 > wq_numa_store 805 433 -372 > wq_cpumask_store 789 402 -387 > apply_workqueue_attrs 538 147 -391 > workqueue_set_unbound_cpumask 947 539 -408 > Total: Before=14422603, After=14420883, chg -0.01% > > So it's both win-win in terms of resolving section mismatch and > saving some text size (-1.7 Kb is quite nice). > > Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Thanks for the patch. See this thread: https://github.com/ClangBuiltLinux/linux/issues/1302
There's a lot more instances of these based on config. Something like https://github.com/ClangBuiltLinux/linux/issues/1302#issuecomment-807260475 would be more appropriate for fixing all instances, but I think this is more so an issue with the inline cost model in LLVM.
I need to finish off https://reviews.llvm.org/D111456, and request that https://reviews.llvm.org/D111272 which landed in clang-14 get backported to the 13.0.1 release which should also help.
> --- > include/linux/nodemask.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h > index 567c3ddba2c4..55ba2c56f39b 100644 > --- a/include/linux/nodemask.h > +++ b/include/linux/nodemask.h > @@ -266,7 +266,7 @@ static inline int __first_node(const nodemask_t *srcp) > } > > #define next_node(n, src) __next_node((n), &(src)) > -static inline int __next_node(int n, const nodemask_t *srcp) > +static __always_inline int __next_node(int n, const nodemask_t *srcp) > { > return min_t(int,MAX_NUMNODES,find_next_bit(srcp->bits, MAX_NUMNODES, n+1)); > } > -- > 2.33.1 >
-- Thanks, ~Nick Desaulniers
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