On Mon, Jun 07, 2021 at 05:18:21PM +0800, Rong Chen wrote: > > On 6/6/21 12:49 PM, Paul E. McKenney wrote: >> On Sun, Jun 06, 2021 at 12:19:57PM +0800, kernel test robot wrote: >>> Hi Paul, >>> >>> FYI, the error/warning still remains. >>> >>> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master >>> head: f5b6eb1e018203913dfefcf6fa988649ad11ad6e >>> commit: 7dffe01765d9309b8bd5505503933ec0ec53d192 rcu: Add lockdep_assert_irqs_disabled() to raw_spin_unlock_rcu_node() macros >>> date: 5 months ago >>> config: powerpc-randconfig-r023-20210606 (attached as .config) >>> compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 551a697c5cf33275b66add4fc467fcf59084cffb) >>> 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 >>> # install powerpc cross compiling tool for clang build >>> # apt-get install binutils-powerpc-linux-gnu >>> # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... >>> git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git >>> git fetch --no-tags linus master >>> git checkout 7dffe01765d9309b8bd5505503933ec0ec53d192 >>> # save the attached .config to linux build tree >>> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc >>> >>> If you fix the issue, kindly add following tag as appropriate >>> Reported-by: kernel test robot <lkp(a)intel.com&gt; >>> >>> All warnings (new ones prefixed by >>): >>> >>> In file included from kernel/rcu/tree.c:21: >>> In file included from include/linux/kernel.h:12: >>> In file included from include/linux/bitops.h:29: >>> In file included from arch/powerpc/include/asm/bitops.h:62: >>> arch/powerpc/include/asm/barrier.h:49:9: warning: '__lwsync' macro redefined [-Wmacro-redefined] >>> #define __lwsync() __asm__ __volatile__ (stringify_in_c(LWSYNC) : : :"memory") >>> ^ >>> <built-in>:310:9: note: previous definition is here >>> #define __lwsync __builtin_ppc_lwsync >>> ^ >>>>> kernel/rcu/tree.c:2073:23: warning: stack frame size of 2704 bytes in function 'rcu_gp_kthread' [-Wframe-larger-than=] >>> static int __noreturn rcu_gp_kthread(void *unused) >> Does -rcu commit 2f20de99a63b ("rcu: Make rcu_gp_cleanup() be noinline >> for tracing") help? > Hi Paul, > > The stack frame size decreased to 2256 bytes: > >   kernel/rcu/tree.c:2129:23: warning: stack frame size of 2256 bytes in > function 'rcu_gp_kthread' [-Wframe-larger-than=] Very good, thank you! Does the following patch (in addition to that commit) also help?

Thanx, Paul ------------------------------------------------------------------------ diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 13bd8eee62bf..ef435aeac993 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1737,7 +1737,7 @@ static void rcu_strict_gp_boundary(void *unused) /* * Initialize a new grace period. Return false if no grace period required. */ -static bool rcu_gp_init(void) +static noinline bool rcu_gp_init(void) { unsigned long firstseq; unsigned long flags; @@ -1931,7 +1931,7 @@ static void rcu_gp_fqs(bool first_time) /* * Loop doing repeated quiescent-state forcing until the grace period ends. */ -static void rcu_gp_fqs_loop(void) +static noinline void rcu_gp_fqs_loop(void) { bool first_gp_fqs; int gf = 0;

On Tue, Jun 08, 2021 at 11:14:40AM +0800, Rong Chen wrote: > > On 6/7/21 11:19 PM, Paul E. McKenney wrote: >> On Mon, Jun 07, 2021 at 05:18:21PM +0800, Rong Chen wrote: >>> On 6/6/21 12:49 PM, Paul E. McKenney wrote: >>>> On Sun, Jun 06, 2021 at 12:19:57PM +0800, kernel test robot wrote: >>>>> Hi Paul, >>>>> >>>>> FYI, the error/warning still remains. >>>>> >>>>> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master >>>>> head: f5b6eb1e018203913dfefcf6fa988649ad11ad6e >>>>> commit: 7dffe01765d9309b8bd5505503933ec0ec53d192 rcu: Add lockdep_assert_irqs_disabled() to raw_spin_unlock_rcu_node() macros >>>>> date: 5 months ago >>>>> config: powerpc-randconfig-r023-20210606 (attached as .config) >>>>> compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 551a697c5cf33275b66add4fc467fcf59084cffb) >>>>> 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 >>>>> # install powerpc cross compiling tool for clang build >>>>> # apt-get install binutils-powerpc-linux-gnu >>>>> # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... >>>>> git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git >>>>> git fetch --no-tags linus master >>>>> git checkout 7dffe01765d9309b8bd5505503933ec0ec53d192 >>>>> # save the attached .config to linux build tree >>>>> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc >>>>> >>>>> If you fix the issue, kindly add following tag as appropriate >>>>> Reported-by: kernel test robot <lkp(a)intel.com&gt; >>>>> >>>>> All warnings (new ones prefixed by >>): >>>>> >>>>> In file included from kernel/rcu/tree.c:21: >>>>> In file included from include/linux/kernel.h:12: >>>>> In file included from include/linux/bitops.h:29: >>>>> In file included from arch/powerpc/include/asm/bitops.h:62: >>>>> arch/powerpc/include/asm/barrier.h:49:9: warning: '__lwsync' macro redefined [-Wmacro-redefined] >>>>> #define __lwsync() __asm__ __volatile__ (stringify_in_c(LWSYNC) : : :"memory") >>>>> ^ >>>>> <built-in>:310:9: note: previous definition is here >>>>> #define __lwsync __builtin_ppc_lwsync >>>>> ^ >>>>>>> kernel/rcu/tree.c:2073:23: warning: stack frame size of 2704 bytes in function 'rcu_gp_kthread' [-Wframe-larger-than=] >>>>> static int __noreturn rcu_gp_kthread(void *unused) >>>> Does -rcu commit 2f20de99a63b ("rcu: Make rcu_gp_cleanup() be noinline >>>> for tracing") help? >>> Hi Paul, >>> >>> The stack frame size decreased to 2256 bytes: >>> >>>   kernel/rcu/tree.c:2129:23: warning: stack frame size of 2256 bytes in >>> function 'rcu_gp_kthread' [-Wframe-larger-than=] >> Very good, thank you! Does the following patch (in addition to that >> commit) also help? > Hi Paul, > > I applied the below patch on commit 2f20de99a63b and the warning is gone. Very good, and thank you for your testing. I have applied the requested Reported-by and your Tested-by on the commit shown below. Please let me know if you would prefer some other Reported/Tested setup. Thanx, Paul

------------------------------------------------------------------------ commit 336e92638287615d47c07af4ff6feb397cfe2084 Author: Paul E. McKenney <paulmck(a)kernel.org&gt; Date: Mon Jun 7 21:57:02 2021 -0700 rcu: Make rcu_gp_init() and rcu_gp_fqs_loop noinline to conserve stack The kbuild test project found an oversized stack frame in rcu_gp_kthread() for some kernel configurations. This oversizing was due to a very large amount of inlining, which is unnecessary due to the fact that this code executes infrequently. This commit therefore marks rcu_gp_init() and rcu_gp_fqs_loop noinline to conserve stack space. Reported-by: kernel test robot <lkp(a)intel.com&gt; Tested-by: Rong Chen <rong.a.chen(a)intel.com&gt; Signed-off-by: Paul E. McKenney <paulmck(a)kernel.org&gt; diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 13bd8eee62bf..ef435aeac993 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1737,7 +1737,7 @@ static void rcu_strict_gp_boundary(void *unused) /* * Initialize a new grace period. Return false if no grace period required. */ -static bool rcu_gp_init(void) +static noinline bool rcu_gp_init(void) { unsigned long firstseq; unsigned long flags; @@ -1931,7 +1931,7 @@ static void rcu_gp_fqs(bool first_time) /* * Loop doing repeated quiescent-state forcing until the grace period ends. */ -static void rcu_gp_fqs_loop(void) +static noinline void rcu_gp_fqs_loop(void) { bool first_gp_fqs; int gf = 0;

On 6/7/2021 10:01 PM, Paul E. McKenney wrote: > On Tue, Jun 08, 2021 at 11:14:40AM +0800, Rong Chen wrote: > > > > > > On 6/7/21 11:19 PM, Paul E. McKenney wrote: > > > On Mon, Jun 07, 2021 at 05:18:21PM +0800, Rong Chen wrote: > > > > > > > > On 6/6/21 12:49 PM, Paul E. McKenney wrote: > > > > > On Sun, Jun 06, 2021 at 12:19:57PM +0800, kernel test robot wrote: > > > > > > Hi Paul, > > > > > > > > > > > > FYI, the error/warning still remains. > > > > > > > > > > > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master > > > > > > head: f5b6eb1e018203913dfefcf6fa988649ad11ad6e > > > > > > commit: 7dffe01765d9309b8bd5505503933ec0ec53d192 rcu: Add lockdep_assert_irqs_disabled() to raw_spin_unlock_rcu_node() macros > > > > > > date: 5 months ago > > > > > > config: powerpc-randconfig-r023-20210606 (attached as .config) > > > > > > compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 551a697c5cf33275b66add4fc467fcf59084cffb) > > > > > > 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 > > > > > > # install powerpc cross compiling tool for clang build > > > > > > # apt-get install binutils-powerpc-linux-gnu > > > > > > # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... > > > > > > git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > > > > > > git fetch --no-tags linus master > > > > > > git checkout 7dffe01765d9309b8bd5505503933ec0ec53d192 > > > > > > # save the attached .config to linux build tree > > > > > > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc > > > > > > > > > > > > If you fix the issue, kindly add following tag as appropriate > > > > > > Reported-by: kernel test robot <lkp(a)intel.com&gt; > > > > > > > > > > > > All warnings (new ones prefixed by >>): > > > > > > > > > > > > In file included from kernel/rcu/tree.c:21: > > > > > > In file included from include/linux/kernel.h:12: > > > > > > In file included from include/linux/bitops.h:29: > > > > > > In file included from arch/powerpc/include/asm/bitops.h:62: > > > > > > arch/powerpc/include/asm/barrier.h:49:9: warning: '__lwsync' macro redefined [-Wmacro-redefined] > > > > > > #define __lwsync() __asm__ __volatile__ (stringify_in_c(LWSYNC) : : :"memory") > > > > > > ^ > > > > > > <built-in>:310:9: note: previous definition is here > > > > > > #define __lwsync __builtin_ppc_lwsync > > > > > > ^ > > > > > > > > kernel/rcu/tree.c:2073:23: warning: stack frame size of 2704 bytes in function 'rcu_gp_kthread' [-Wframe-larger-than=] > > > > > > static int __noreturn rcu_gp_kthread(void *unused) > > > > > Does -rcu commit 2f20de99a63b ("rcu: Make rcu_gp_cleanup() be noinline > > > > > for tracing") help? > > > > Hi Paul, > > > > > > > > The stack frame size decreased to 2256 bytes: > > > > > > > >   kernel/rcu/tree.c:2129:23: warning: stack frame size of 2256 bytes in > > > > function 'rcu_gp_kthread' [-Wframe-larger-than=] > > > Very good, thank you! Does the following patch (in addition to that > > > commit) also help? > > > > Hi Paul, > > > > I applied the below patch on commit 2f20de99a63b and the warning is gone. > > Very good, and thank you for your testing. I have applied the requested > Reported-by and your Tested-by on the commit shown below. Please let > me know if you would prefer some other Reported/Tested setup. > > Thanx, Paul > > ------------------------------------------------------------------------ > > commit 336e92638287615d47c07af4ff6feb397cfe2084 > Author: Paul E. McKenney <paulmck(a)kernel.org&gt; > Date: Mon Jun 7 21:57:02 2021 -0700 > > rcu: Make rcu_gp_init() and rcu_gp_fqs_loop noinline to conserve stack > The kbuild test project found an oversized stack frame in rcu_gp_kthread() > for some kernel configurations. This oversizing was due to a very large > amount of inlining, which is unnecessary due to the fact that this code > executes infrequently. This commit therefore marks rcu_gp_init() and > rcu_gp_fqs_loop noinline to conserve stack space. > Reported-by: kernel test robot <lkp(a)intel.com&gt; > Tested-by: Rong Chen <rong.a.chen(a)intel.com&gt; > Signed-off-by: Paul E. McKenney <paulmck(a)kernel.org&gt; > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > index 13bd8eee62bf..ef435aeac993 100644 > --- a/kernel/rcu/tree.c > +++ b/kernel/rcu/tree.c > @@ -1737,7 +1737,7 @@ static void rcu_strict_gp_boundary(void *unused) > /* > * Initialize a new grace period. Return false if no grace period required. > */ > -static bool rcu_gp_init(void) > +static noinline bool rcu_gp_init(void) Small comment if it is not too late. noinline_for_stack expands to the same thing but is self documenting :) that way people do not have to git blame to see why these are marked as noinline (not that too many people are probably touching this but still).

On 6/8/2021 8:58 PM, Paul E. McKenney wrote: > On Tue, Jun 08, 2021 at 08:53:17AM -0700, Nathan Chancellor wrote: > > On 6/7/2021 10:01 PM, Paul E. McKenney wrote: > > > On Tue, Jun 08, 2021 at 11:14:40AM +0800, Rong Chen wrote: > > > > > > > > > > > > On 6/7/21 11:19 PM, Paul E. McKenney wrote: > > > > > On Mon, Jun 07, 2021 at 05:18:21PM +0800, Rong Chen wrote: > > > > > > > > > > > > On 6/6/21 12:49 PM, Paul E. McKenney wrote: > > > > > > > On Sun, Jun 06, 2021 at 12:19:57PM +0800, kernel test robot wrote: > > > > > > > > Hi Paul, > > > > > > > > > > > > > > > > FYI, the error/warning still remains. > > > > > > > > > > > > > > > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master > > > > > > > > head: f5b6eb1e018203913dfefcf6fa988649ad11ad6e > > > > > > > > commit: 7dffe01765d9309b8bd5505503933ec0ec53d192 rcu: Add lockdep_assert_irqs_disabled() to raw_spin_unlock_rcu_node() macros > > > > > > > > date: 5 months ago > > > > > > > > config: powerpc-randconfig-r023-20210606 (attached as .config) > > > > > > > > compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 551a697c5cf33275b66add4fc467fcf59084cffb) > > > > > > > > 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 > > > > > > > > # install powerpc cross compiling tool for clang build > > > > > > > > # apt-get install binutils-powerpc-linux-gnu > > > > > > > > # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... > > > > > > > > git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > > > > > > > > git fetch --no-tags linus master > > > > > > > > git checkout 7dffe01765d9309b8bd5505503933ec0ec53d192 > > > > > > > > # save the attached .config to linux build tree > > > > > > > > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc > > > > > > > > > > > > > > > > If you fix the issue, kindly add following tag as appropriate > > > > > > > > Reported-by: kernel test robot <lkp(a)intel.com&gt; > > > > > > > > > > > > > > > > All warnings (new ones prefixed by >>): > > > > > > > > > > > > > > > > In file included from kernel/rcu/tree.c:21: > > > > > > > > In file included from include/linux/kernel.h:12: > > > > > > > > In file included from include/linux/bitops.h:29: > > > > > > > > In file included from arch/powerpc/include/asm/bitops.h:62: > > > > > > > > arch/powerpc/include/asm/barrier.h:49:9: warning: '__lwsync' macro redefined [-Wmacro-redefined] > > > > > > > > #define __lwsync() __asm__ __volatile__ (stringify_in_c(LWSYNC) : : :"memory") > > > > > > > > ^ > > > > > > > > <built-in>:310:9: note: previous definition is here > > > > > > > > #define __lwsync __builtin_ppc_lwsync > > > > > > > > ^ > > > > > > > > > > kernel/rcu/tree.c:2073:23: warning: stack frame size of 2704 bytes in function 'rcu_gp_kthread' [-Wframe-larger-than=] > > > > > > > > static int __noreturn rcu_gp_kthread(void *unused) > > > > > > > Does -rcu commit 2f20de99a63b ("rcu: Make rcu_gp_cleanup() be noinline > > > > > > > for tracing") help? > > > > > > Hi Paul, > > > > > > > > > > > > The stack frame size decreased to 2256 bytes: > > > > > > > > > > > >   kernel/rcu/tree.c:2129:23: warning: stack frame size of 2256 bytes in > > > > > > function 'rcu_gp_kthread' [-Wframe-larger-than=] > > > > > Very good, thank you! Does the following patch (in addition to that > > > > > commit) also help? > > > > > > > > Hi Paul, > > > > > > > > I applied the below patch on commit 2f20de99a63b and the warning is gone. > > > > > > Very good, and thank you for your testing. I have applied the requested > > > Reported-by and your Tested-by on the commit shown below. Please let > > > me know if you would prefer some other Reported/Tested setup. > > > > > > Thanx, Paul > > > > > > ------------------------------------------------------------------------ > > > > > > commit 336e92638287615d47c07af4ff6feb397cfe2084 > > > Author: Paul E. McKenney <paulmck(a)kernel.org&gt; > > > Date: Mon Jun 7 21:57:02 2021 -0700 > > > > > > rcu: Make rcu_gp_init() and rcu_gp_fqs_loop noinline to conserve stack > > > The kbuild test project found an oversized stack frame in rcu_gp_kthread() > > > for some kernel configurations. This oversizing was due to a very large > > > amount of inlining, which is unnecessary due to the fact that this code > > > executes infrequently. This commit therefore marks rcu_gp_init() and > > > rcu_gp_fqs_loop noinline to conserve stack space. > > > Reported-by: kernel test robot <lkp(a)intel.com&gt; > > > Tested-by: Rong Chen <rong.a.chen(a)intel.com&gt; > > > Signed-off-by: Paul E. McKenney <paulmck(a)kernel.org&gt; > > > > > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > > > index 13bd8eee62bf..ef435aeac993 100644 > > > --- a/kernel/rcu/tree.c > > > +++ b/kernel/rcu/tree.c > > > @@ -1737,7 +1737,7 @@ static void rcu_strict_gp_boundary(void *unused) > > > /* > > > * Initialize a new grace period. Return false if no grace period required. > > > */ > > > -static bool rcu_gp_init(void) > > > +static noinline bool rcu_gp_init(void) > > > > Small comment if it is not too late. noinline_for_stack expands to the same > > thing but is self documenting :) that way people do not have to git blame to > > see why these are marked as noinline (not that too many people are probably > > touching this but still). > > How about like the following? > > Thanx, Paul > > ------------------------------------------------------------------------ > > commit 8aa0ceef4264012abd7b98d29f0a968f0f0046cb > Author: Paul E. McKenney <paulmck(a)kernel.org&gt; > Date: Mon Jun 7 21:57:02 2021 -0700 > > rcu: Make rcu_gp_init() and rcu_gp_fqs_loop noinline to conserve stack > The kbuild test project found an oversized stack frame in rcu_gp_kthread() > for some kernel configurations. This oversizing was due to a very large > amount of inlining, which is unnecessary due to the fact that this code > executes infrequently. This commit therefore marks rcu_gp_init() and > rcu_gp_fqs_loop noinline_for_stack to conserve stack space. > Reported-by: kernel test robot <lkp(a)intel.com&gt; > Tested-by: Rong Chen <rong.a.chen(a)intel.com&gt; > [ paulmck: noinline_for_stack per Nathan Chancellor. ] > Signed-off-by: Paul E. McKenney <paulmck(a)kernel.org&gt; Reviewed-by: Nathan Chancellor <nathan(a)kernel.org&gt;