tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched/core
head: b2d5b9cec60fecc72a13191c2c6c05acf60975a5
commit: 60f2415e19d3948641149ac6aca137a7be1d1952 [14/47] sched: Make schedstats helpers independent of fair sched class
config: hexagon-buildonly-randconfig-r002-20211012 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project c3dcf39554dbea780d6cb7e12239451ba47a2668)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=60f2415e19d3948641149ac6aca137a7be1d1952
git remote add tip https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git
git fetch --no-tags tip sched/core
git checkout 60f2415e19d3948641149ac6aca137a7be1d1952
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=hexagon
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>):
kernel/sched/fair.c:860:28: error: variable 'stats' set but not used [-Werror,-Wunused-but-set-variable]
struct sched_statistics *stats;
^
kernel/sched/fair.c:892:27: error: variable 'stats' set but not used [-Werror,-Wunused-but-set-variable]
struct sched_statistics *stats;
^
>> kernel/sched/fair.c:893:22: error: variable 'p' set but not used [-Werror,-Wunused-but-set-variable]
struct task_struct *p = NULL;
^
kernel/sched/fair.c:910:22: error: variable 'p' set but not used [-Werror,-Wunused-but-set-variable]
struct task_struct *p = NULL;
^
kernel/sched/fair.c:909:27: error: variable 'stats' set but not used [-Werror,-Wunused-but-set-variable]
struct sched_statistics *stats;
^
>> kernel/sched/fair.c:936:22: error: variable 'tsk' set but not used [-Werror,-Wunused-but-set-variable]
struct task_struct *tsk = NULL;
^
kernel/sched/fair.c:935:27: error: variable 'stats' set but not used [-Werror,-Wunused-but-set-variable]
struct sched_statistics *stats;
^
kernel/sched/fair.c:4451:28: error: variable 'stats' set but not used [-Werror,-Wunused-but-set-variable]
struct sched_statistics *stats;
^
8 errors generated.
vim +/p +893 kernel/sched/fair.c
840
841 /*
842 * Update the current task's runtime statistics.
843 */
844 static void update_curr(struct cfs_rq *cfs_rq)
845 {
846 struct sched_entity *curr = cfs_rq->curr;
847 u64 now = rq_clock_task(rq_of(cfs_rq));
848 u64 delta_exec;
849
850 if (unlikely(!curr))
851 return;
852
853 delta_exec = now - curr->exec_start;
854 if (unlikely((s64)delta_exec <= 0))
855 return;
856
857 curr->exec_start = now;
858
859 if (schedstat_enabled()) {
> 860 struct sched_statistics *stats;
861
862 stats = __schedstats_from_se(curr);
863 __schedstat_set(stats->exec_max,
864 max(delta_exec, stats->exec_max));
865 }
866
867 curr->sum_exec_runtime += delta_exec;
868 schedstat_add(cfs_rq->exec_clock, delta_exec);
869
870 curr->vruntime += calc_delta_fair(delta_exec, curr);
871 update_min_vruntime(cfs_rq);
872
873 if (entity_is_task(curr)) {
874 struct task_struct *curtask = task_of(curr);
875
876 trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime);
877 cgroup_account_cputime(curtask, delta_exec);
878 account_group_exec_runtime(curtask, delta_exec);
879 }
880
881 account_cfs_rq_runtime(cfs_rq, delta_exec);
882 }
883
884 static void update_curr_fair(struct rq *rq)
885 {
886 update_curr(cfs_rq_of(&rq->curr->se));
887 }
888
889 static inline void
890 update_stats_wait_start_fair(struct cfs_rq *cfs_rq, struct sched_entity *se)
891 {
892 struct sched_statistics *stats;
> 893 struct task_struct *p = NULL;
894
895 if (!schedstat_enabled())
896 return;
897
898 stats = __schedstats_from_se(se);
899
900 if (entity_is_task(se))
901 p = task_of(se);
902
903 __update_stats_wait_start(rq_of(cfs_rq), p, stats);
904 }
905
906 static inline void
907 update_stats_wait_end_fair(struct cfs_rq *cfs_rq, struct sched_entity *se)
908 {
909 struct sched_statistics *stats;
910 struct task_struct *p = NULL;
911
912 if (!schedstat_enabled())
913 return;
914
915 stats = __schedstats_from_se(se);
916
917 /*
918 * When the sched_schedstat changes from 0 to 1, some sched se
919 * maybe already in the runqueue, the se->statistics.wait_start
920 * will be 0.So it will let the delta wrong. We need to avoid this
921 * scenario.
922 */
923 if (unlikely(!schedstat_val(stats->wait_start)))
924 return;
925
926 if (entity_is_task(se))
927 p = task_of(se);
928
929 __update_stats_wait_end(rq_of(cfs_rq), p, stats);
930 }
931
932 static inline void
933 update_stats_enqueue_sleeper_fair(struct cfs_rq *cfs_rq, struct sched_entity *se)
934 {
935 struct sched_statistics *stats;
> 936 struct task_struct *tsk = NULL;
937
938 if (!schedstat_enabled())
939 return;
940
941 stats = __schedstats_from_se(se);
942
943 if (entity_is_task(se))
944 tsk = task_of(se);
945
946 __update_stats_enqueue_sleeper(rq_of(cfs_rq), tsk, stats);
947 }
948
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
On Tue, Oct 12, 2021 at 11:57:41AM +0800, kernel test robot wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched/core
> head: b2d5b9cec60fecc72a13191c2c6c05acf60975a5
> commit: 60f2415e19d3948641149ac6aca137a7be1d1952 [14/47] sched: Make schedstats helpers independent of fair sched class
> config: hexagon-buildonly-randconfig-r002-20211012 (attached as .config)
> compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project c3dcf39554dbea780d6cb7e12239451ba47a2668)
> reproduce (this is a W=1 build):
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=60f2415e19d3948641149ac6aca137a7be1d1952
> git remote add tip https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git
> git fetch --no-tags tip sched/core
> git checkout 60f2415e19d3948641149ac6aca137a7be1d1952
> # save the attached .config to linux build tree
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=hexagon
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <[email protected]>
>
> All errors (new ones prefixed by >>):
>
> kernel/sched/fair.c:860:28: error: variable 'stats' set but not used [-Werror,-Wunused-but-set-variable]
> struct sched_statistics *stats;
> ^
> kernel/sched/fair.c:892:27: error: variable 'stats' set but not used [-Werror,-Wunused-but-set-variable]
> struct sched_statistics *stats;
> ^
> >> kernel/sched/fair.c:893:22: error: variable 'p' set but not used [-Werror,-Wunused-but-set-variable]
> struct task_struct *p = NULL;
> ^
> kernel/sched/fair.c:910:22: error: variable 'p' set but not used [-Werror,-Wunused-but-set-variable]
> struct task_struct *p = NULL;
> ^
> kernel/sched/fair.c:909:27: error: variable 'stats' set but not used [-Werror,-Wunused-but-set-variable]
> struct sched_statistics *stats;
> ^
> >> kernel/sched/fair.c:936:22: error: variable 'tsk' set but not used [-Werror,-Wunused-but-set-variable]
> struct task_struct *tsk = NULL;
> ^
> kernel/sched/fair.c:935:27: error: variable 'stats' set but not used [-Werror,-Wunused-but-set-variable]
> struct sched_statistics *stats;
> ^
> kernel/sched/fair.c:4451:28: error: variable 'stats' set but not used [-Werror,-Wunused-but-set-variable]
> struct sched_statistics *stats;
> ^
> 8 errors generated.
Again, I have absolutely no intention of fixing this. IMO this is the
compiler being a total pain in the arse.
Please stop reporting this.
On Tue, Oct 12, 2021 at 01:26:54PM +0200, Peter Zijlstra wrote:
> Again, I have absolutely no intention of fixing this. IMO this is the
> compiler being a total pain in the arse.
>
> Please stop reporting this.
How's this then?
diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
index 978fcfca5871..b0d9121c5dce 100644
--- a/kernel/sched/Makefile
+++ b/kernel/sched/Makefile
@@ -3,6 +3,10 @@ ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_clock.o = $(CC_FLAGS_FTRACE)
endif
+# The compilers are complaining about unused variables inside an if(0) scope
+# block. This is daft, shut them up.
+ccflags-y += -Wno-unused-but-set-variable
+
# These files are disabled because they produce non-interesting flaky coverage
# that is not a function of syscall inputs. E.g. involuntary context switches.
KCOV_INSTRUMENT := n
On 10/12/2021 7:26 PM, Peter Zijlstra wrote:
> On Tue, Oct 12, 2021 at 11:57:41AM +0800, kernel test robot wrote:
>> tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched/core
>> head: b2d5b9cec60fecc72a13191c2c6c05acf60975a5
>> commit: 60f2415e19d3948641149ac6aca137a7be1d1952 [14/47] sched: Make schedstats helpers independent of fair sched class
>> config: hexagon-buildonly-randconfig-r002-20211012 (attached as .config)
>> compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project c3dcf39554dbea780d6cb7e12239451ba47a2668)
>> reproduce (this is a W=1 build):
>> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>> chmod +x ~/bin/make.cross
>> # https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=60f2415e19d3948641149ac6aca137a7be1d1952
>> git remote add tip https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git
>> git fetch --no-tags tip sched/core
>> git checkout 60f2415e19d3948641149ac6aca137a7be1d1952
>> # save the attached .config to linux build tree
>> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=hexagon
>>
>> If you fix the issue, kindly add following tag as appropriate
>> Reported-by: kernel test robot <[email protected]>
>>
>> All errors (new ones prefixed by >>):
>>
>> kernel/sched/fair.c:860:28: error: variable 'stats' set but not used [-Werror,-Wunused-but-set-variable]
>> struct sched_statistics *stats;
>> ^
>> kernel/sched/fair.c:892:27: error: variable 'stats' set but not used [-Werror,-Wunused-but-set-variable]
>> struct sched_statistics *stats;
>> ^
>>>> kernel/sched/fair.c:893:22: error: variable 'p' set but not used [-Werror,-Wunused-but-set-variable]
>> struct task_struct *p = NULL;
>> ^
>> kernel/sched/fair.c:910:22: error: variable 'p' set but not used [-Werror,-Wunused-but-set-variable]
>> struct task_struct *p = NULL;
>> ^
>> kernel/sched/fair.c:909:27: error: variable 'stats' set but not used [-Werror,-Wunused-but-set-variable]
>> struct sched_statistics *stats;
>> ^
>>>> kernel/sched/fair.c:936:22: error: variable 'tsk' set but not used [-Werror,-Wunused-but-set-variable]
>> struct task_struct *tsk = NULL;
>> ^
>> kernel/sched/fair.c:935:27: error: variable 'stats' set but not used [-Werror,-Wunused-but-set-variable]
>> struct sched_statistics *stats;
>> ^
>> kernel/sched/fair.c:4451:28: error: variable 'stats' set but not used [-Werror,-Wunused-but-set-variable]
>> struct sched_statistics *stats;
>> ^
>> 8 errors generated.
>
> Again, I have absolutely no intention of fixing this. IMO this is the
> compiler being a total pain in the arse.
>
> Please stop reporting this.
Hi Peterz,
Sorry for the noise, we'll ignore the unused-but-set-variable warning in
kernel/sched/ part. Is there any other issue should be ignored?
Best Regards,
Rong Chen
On Tue, Oct 12, 2021 at 9:35 PM Peter Zijlstra <[email protected]> wrote:
>
> On Tue, Oct 12, 2021 at 01:26:54PM +0200, Peter Zijlstra wrote:
>
> > Again, I have absolutely no intention of fixing this. IMO this is the
> > compiler being a total pain in the arse.
> >
> > Please stop reporting this.
>
> How's this then?
>
> diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
> index 978fcfca5871..b0d9121c5dce 100644
> --- a/kernel/sched/Makefile
> +++ b/kernel/sched/Makefile
> @@ -3,6 +3,10 @@ ifdef CONFIG_FUNCTION_TRACER
> CFLAGS_REMOVE_clock.o = $(CC_FLAGS_FTRACE)
> endif
>
> +# The compilers are complaining about unused variables inside an if(0) scope
> +# block. This is daft, shut them up.
> +ccflags-y += -Wno-unused-but-set-variable
> +
> # These files are disabled because they produce non-interesting flaky coverage
> # that is not a function of syscall inputs. E.g. involuntary context switches.
> KCOV_INSTRUMENT := n
After this diff, the warnings disappear.
Tested-by: Yafang Shao <[email protected]>
--
Thanks
Yafang
On Tue, Oct 12, 2021 at 03:35:42PM +0200, Peter Zijlstra wrote:
> On Tue, Oct 12, 2021 at 01:26:54PM +0200, Peter Zijlstra wrote:
>
> > Again, I have absolutely no intention of fixing this. IMO this is the
> > compiler being a total pain in the arse.
> >
> > Please stop reporting this.
>
> How's this then?
>
> diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
> index 978fcfca5871..b0d9121c5dce 100644
> --- a/kernel/sched/Makefile
> +++ b/kernel/sched/Makefile
> @@ -3,6 +3,10 @@ ifdef CONFIG_FUNCTION_TRACER
> CFLAGS_REMOVE_clock.o = $(CC_FLAGS_FTRACE)
> endif
>
> +# The compilers are complaining about unused variables inside an if(0) scope
> +# block. This is daft, shut them up.
> +ccflags-y += -Wno-unused-but-set-variable
Please consider making this
ccflags-y += $(call cc-disable-warning, unused-but-set-variable)
because -Wunused-but-set-variable was only added to clang in the 13
release but we support back to 10, meaning this will cause errors for
those older compilers.
With that:
Reviewed-by: Nathan Chancellor <[email protected]>
Additionally, perhaps this could be restricted to just fair.c?
> +
> # These files are disabled because they produce non-interesting flaky coverage
> # that is not a function of syscall inputs. E.g. involuntary context switches.
> KCOV_INSTRUMENT := n
>
On Wed, Oct 13, 2021 at 09:23:56PM -0700, Nathan Chancellor wrote:
> On Tue, Oct 12, 2021 at 03:35:42PM +0200, Peter Zijlstra wrote:
> > On Tue, Oct 12, 2021 at 01:26:54PM +0200, Peter Zijlstra wrote:
> >
> > > Again, I have absolutely no intention of fixing this. IMO this is the
> > > compiler being a total pain in the arse.
> > >
> > > Please stop reporting this.
> >
> > How's this then?
> >
> > diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
> > index 978fcfca5871..b0d9121c5dce 100644
> > --- a/kernel/sched/Makefile
> > +++ b/kernel/sched/Makefile
> > @@ -3,6 +3,10 @@ ifdef CONFIG_FUNCTION_TRACER
> > CFLAGS_REMOVE_clock.o = $(CC_FLAGS_FTRACE)
> > endif
> >
> > +# The compilers are complaining about unused variables inside an if(0) scope
> > +# block. This is daft, shut them up.
> > +ccflags-y += -Wno-unused-but-set-variable
>
> Please consider making this
>
> ccflags-y += $(call cc-disable-warning, unused-but-set-variable)
Ooh, shiny, will do.
> because -Wunused-but-set-variable was only added to clang in the 13
> release but we support back to 10, meaning this will cause errors for
> those older compilers.
>
> With that:
>
> Reviewed-by: Nathan Chancellor <[email protected]>
>
> Additionally, perhaps this could be restricted to just fair.c?
It triggers in a bunch of files, given the right config (defconfig -SCHEDSTATS +SCHED_DEBUG)
(and I have a pile of patches for most of the other warnings somewhere...)
---
# make O=defconfig-build/ kernel/sched/ -j8 -s W=1
../kernel/sched/deadline.c: In function ‘update_stats_wait_start_dl’:
../kernel/sched/deadline.c:1486:27: warning: variable ‘stats’ set but not used [-Wunused-but-set-variable]
1486 | struct sched_statistics *stats;
| ^~~~~
../kernel/sched/deadline.c: In function ‘update_stats_wait_end_dl’:
../kernel/sched/deadline.c:1498:27: warning: variable ‘stats’ set but not used [-Wunused-but-set-variable]
1498 | struct sched_statistics *stats;
| ^~~~~
../kernel/sched/deadline.c: In function ‘update_stats_enqueue_sleeper_dl’:
../kernel/sched/deadline.c:1510:27: warning: variable ‘stats’ set but not used [-Wunused-but-set-variable]
1510 | struct sched_statistics *stats;
| ^~~~~
../kernel/sched/fair.c: In function ‘update_curr’:
../kernel/sched/fair.c:860:28: warning: variable ‘stats’ set but not used [-Wunused-but-set-variable]
860 | struct sched_statistics *stats;
| ^~~~~
../kernel/sched/fair.c: In function ‘update_stats_wait_start_fair’:
../kernel/sched/fair.c:893:22: warning: variable ‘p’ set but not used [-Wunused-but-set-variable]
893 | struct task_struct *p = NULL;
| ^
../kernel/sched/fair.c:892:27: warning: variable ‘stats’ set but not used [-Wunused-but-set-variable]
892 | struct sched_statistics *stats;
| ^~~~~
../kernel/sched/fair.c: In function ‘update_stats_wait_end_fair’:
../kernel/sched/fair.c:910:22: warning: variable ‘p’ set but not used [-Wunused-but-set-variable]
910 | struct task_struct *p = NULL;
| ^
../kernel/sched/fair.c:909:27: warning: variable ‘stats’ set but not used [-Wunused-but-set-variable]
909 | struct sched_statistics *stats;
| ^~~~~
../kernel/sched/fair.c: In function ‘update_stats_enqueue_sleeper_fair’:
../kernel/sched/fair.c:936:22: warning: variable ‘tsk’ set but not used [-Wunused-but-set-variable]
936 | struct task_struct *tsk = NULL;
| ^~~
../kernel/sched/fair.c:935:27: warning: variable ‘stats’ set but not used [-Wunused-but-set-variable]
935 | struct sched_statistics *stats;
| ^~~~~
../kernel/sched/fair.c: In function ‘set_next_entity’:
../kernel/sched/fair.c:4450:28: warning: variable ‘stats’ set but not used [-Wunused-but-set-variable]
4450 | struct sched_statistics *stats;
| ^~~~~
../kernel/sched/rt.c:669:6: warning: no previous prototype for ‘sched_rt_bandwidth_account’ [-Wmissing-prototypes]
669 | bool sched_rt_bandwidth_account(struct rt_rq *rt_rq)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
../kernel/sched/rt.c: In function ‘update_stats_wait_start_rt’:
../kernel/sched/rt.c:1292:22: warning: variable ‘p’ set but not used [-Wunused-but-set-variable]
1292 | struct task_struct *p = NULL;
| ^
../kernel/sched/rt.c: In function ‘update_stats_enqueue_sleeper_rt’:
../kernel/sched/rt.c:1311:22: warning: variable ‘p’ set but not used [-Wunused-but-set-variable]
1311 | struct task_struct *p = NULL;
| ^
../kernel/sched/rt.c: In function ‘update_stats_wait_end_rt’:
../kernel/sched/rt.c:1341:22: warning: variable ‘p’ set but not used [-Wunused-but-set-variable]
1341 | struct task_struct *p = NULL;
| ^
../kernel/sched/core.c:3420:6: warning: no previous prototype for ‘sched_set_stop_task’ [-Wmissing-prototypes]
3420 | void sched_set_stop_task(int cpu, struct task_struct *stop)
| ^~~~~~~~~~~~~~~~~~~
../kernel/sched/debug.c: In function ‘print_cfs_group_stats’:
../kernel/sched/debug.c:466:28: warning: variable ‘stats’ set but not used [-Wunused-but-set-variable]
466 | struct sched_statistics *stats;
| ^~~~~
../kernel/sched/fair.c:8673: warning: Function parameter or member 'sds' not described in 'update_sg_lb_stats'
The following commit has been merged into the sched/core branch of tip:
Commit-ID: 37b47298ab864fb3f5488ddebfc35267ceab0553
Gitweb: https://git.kernel.org/tip/37b47298ab864fb3f5488ddebfc35267ceab0553
Author: Peter Zijlstra <[email protected]>
AuthorDate: Tue, 12 Oct 2021 16:08:07 +02:00
Committer: Peter Zijlstra <[email protected]>
CommitterDate: Fri, 15 Oct 2021 11:25:15 +02:00
sched: Disable -Wunused-but-set-variable
The compilers can't deal with obvious DCE vs that warning, resulting
in code like:
if (0) {
sched sched_statistics *stats;
stats = __schedstats_from_se(se);
...
}
triggering the warning. Kill the warning to make the robots stop
reporting this.
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
kernel/sched/Makefile | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
index 978fcfc..c7421f2 100644
--- a/kernel/sched/Makefile
+++ b/kernel/sched/Makefile
@@ -3,6 +3,10 @@ ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_clock.o = $(CC_FLAGS_FTRACE)
endif
+# The compilers are complaining about unused variables inside an if(0) scope
+# block. This is daft, shut them up.
+ccflags-y += $(call cc-disable-warning, unused-but-set-variable)
+
# These files are disabled because they produce non-interesting flaky coverage
# that is not a function of syscall inputs. E.g. involuntary context switches.
KCOV_INSTRUMENT := n