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@lca.pw Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Link: https://lkml.kernel.org/r/1559596304-31581-1-git-send-email-cai@lca.pw Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org
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