On Mon, Jul 29, 2019 at 09:19:05PM +0200, Greg Kroah-Hartman wrote: > [ Upstream commit 509466b7d480bc5d22e90b9fbe6122ae0e2fbe39 ] > > runnable_avg_yN_inv[] is only used in kernel/sched/pelt.c but was > included in several other places because they need other macros all > came from kernel/sched/sched-pelt.h which was generated by > Documentation/scheduler/sched-pelt. As the result, it causes compilation > a lot of warnings, > > kernel/sched/sched-pelt.h:4:18: warning: 'runnable_avg_yN_inv' defined but not used [-Wunused-const-variable=] > kernel/sched/sched-pelt.h:4:18: warning: 'runnable_avg_yN_inv' defined but not used [-Wunused-const-variable=] > kernel/sched/sched-pelt.h:4:18: warning: 'runnable_avg_yN_inv' defined but not used [-Wunused-const-variable=] > ... > > Silence it by appending the __maybe_unused attribute for it, so all > generated variables and macros can still be kept in the same file. > > Signed-off-by: Qian Cai <cai@xxxxxx> > Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> > Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Link: https://lkml.kernel.org/r/1559596304-31581-1-git-send-email-cai@xxxxxx > Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > --- > Documentation/scheduler/sched-pelt.c | 3 ++- > kernel/sched/sched-pelt.h | 2 +- > 2 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/Documentation/scheduler/sched-pelt.c b/Documentation/scheduler/sched-pelt.c > index e4219139386a..7238b355919c 100644 > --- a/Documentation/scheduler/sched-pelt.c > +++ b/Documentation/scheduler/sched-pelt.c > @@ -20,7 +20,8 @@ void calc_runnable_avg_yN_inv(void) > int i; > unsigned int x; > > - printf("static const u32 runnable_avg_yN_inv[] = {"); > + /* To silence -Wunused-but-set-variable warnings. */ > + printf("static const u32 runnable_avg_yN_inv[] __maybe_unused = {"); > for (i = 0; i < HALFLIFE; i++) { > x = ((1UL<<32)-1)*pow(y, i); > > diff --git a/kernel/sched/sched-pelt.h b/kernel/sched/sched-pelt.h > index a26473674fb7..c529706bed11 100644 > --- a/kernel/sched/sched-pelt.h > +++ b/kernel/sched/sched-pelt.h > @@ -1,7 +1,7 @@ > /* SPDX-License-Identifier: GPL-2.0 */ > /* Generated by Documentation/scheduler/sched-pelt; do not modify. */ > > -static const u32 runnable_avg_yN_inv[] = { > +static const u32 runnable_avg_yN_inv[] __maybe_unused = { > 0xffffffff, 0xfa83b2da, 0xf5257d14, 0xefe4b99a, 0xeac0c6e6, 0xe5b906e6, > 0xe0ccdeeb, 0xdbfbb796, 0xd744fcc9, 0xd2a81d91, 0xce248c14, 0xc9b9bd85, > 0xc5672a10, 0xc12c4cc9, 0xbd08a39e, 0xb8fbaf46, 0xb504f333, 0xb123f581, > -- > 2.20.1 > > > This patch does nothing in 4.14. There is no kernel/sched/pelt.c. $ fd pelt kernel/sched/sched-pelt.h Documentation/scheduler/sched-pelt.c runnable_avg_yN_inv is only used in one location in 4.14.134, in fair.c behind CONFIG_SMP, which is also the guard that includes sched-pelt.h. $ rg --no-heading -g '!Documentation' runnable_avg_yN_inv kernel/sched/sched-pelt.h:4:static const u32 runnable_avg_yN_inv[] = { kernel/sched/fair.c:2849: val = mul_u64_u32_shr(val, runnable_avg_yN_inv[local_n], 32); $ rg --no-heading -B 2 "sched-pelt.h" kernel/sched/fair.c-707-#ifdef CONFIG_SMP kernel/sched/fair.c-708- kernel/sched/fair.c:709:#include "sched-pelt.h" I see no way for the warnings in this patch to occur here, making it pointless. I get two trivial conflicts in my msm-4.14 tree from this patch that I would like to avoid dealing with. Please consider dropping this patch, thanks! Nathan
