# git rev-parse -q --verify 4df910620bebb5cfe234af16ac8f6474b60215fd^{commit}
4df910620bebb5cfe234af16ac8f6474b60215fd
already have revision, skipping fetch
# git checkout -q -f -B kisskb 4df910620bebb5cfe234af16ac8f6474b60215fd
# git clean -qxdf
# < git log -1
# commit 4df910620bebb5cfe234af16ac8f6474b60215fd
# Author: Feng Tang <feng.tang@intel.com>
# Date:   Wed Nov 25 13:22:21 2020 +0800
# 
#     mm: memcg: relayout structure mem_cgroup to avoid cache interference
#     
#     0day reported one -22.7% regression for will-it-scale page_fault2
#     case [1] on a 4 sockets 144 CPU platform, and bisected to it to be
#     caused by Waiman's optimization (commit bd0b230fe1) of saving one
#     'struct page_counter' space for 'struct mem_cgroup'.
#     
#     Initially we thought it was due to the cache alignment change introduced
#     by the patch, but further debug shows that it is due to some hot data
#     members ('vmstats_local', 'vmstats_percpu', 'vmstats') sit in 2 adjacent
#     cacheline (2N and 2N+1 cacheline), and when adjacent cache line prefetch
#     is enabled, it triggers an "extended level" of cache false sharing for
#     2 adjacent cache lines.
#     
#     So exchange the 2 member blocks, while keeping mostly the original
#     cache alignment, which can restore and even enhance the performance,
#     and save 64 bytes of space for 'struct mem_cgroup' (from 2880 to 2816,
#     with 0day's default RHEL-8.3 kernel config)
#     
#     [1]. https://lore.kernel.org/lkml/20201102091543.GM31092@shao2-debian/
#     
#     Fixes: bd0b230fe145 ("mm/memcg: unify swap and memsw page counters")
#     Reported-by: kernel test robot <rong.a.chen@intel.com>
#     Signed-off-by: Feng Tang <feng.tang@intel.com>
#     Acked-by: Waiman Long <longman@redhat.com>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/korg/gcc-10.1.0-nolibc/sh4-linux/bin/sh4-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-10.1.0-nolibc/sh4-linux/bin/sh4-linux-ld --version
# < git log --format=%s --max-count=1 4df910620bebb5cfe234af16ac8f6474b60215fd
# < make -s -j 48 ARCH=sh O=/kisskb/build/linus_se7619_defconfig_sh4-gcc10 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-10.1.0-nolibc/sh4-linux/bin/sh4-linux-  se7619_defconfig
# < make -s -j 48 ARCH=sh O=/kisskb/build/linus_se7619_defconfig_sh4-gcc10 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-10.1.0-nolibc/sh4-linux/bin/sh4-linux-  help
# make -s -j 48 ARCH=sh O=/kisskb/build/linus_se7619_defconfig_sh4-gcc10 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-10.1.0-nolibc/sh4-linux/bin/sh4-linux-  olddefconfig
# make -s -j 48 ARCH=sh O=/kisskb/build/linus_se7619_defconfig_sh4-gcc10 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-10.1.0-nolibc/sh4-linux/bin/sh4-linux-  
  Generating include/generated/machtypes.h
<stdin>:1511:2: warning: #warning syscall clone3 not implemented [-Wcpp]
In file included from /kisskb/src/arch/sh/include/asm/hw_irq.h:6,
                 from /kisskb/src/include/linux/irq.h:589,
                 from /kisskb/src/arch/sh/include/asm/hardirq.h:6,
                 from /kisskb/src/include/linux/hardirq.h:10,
                 from /kisskb/src/include/linux/interrupt.h:11,
                 from /kisskb/src/include/linux/serial_core.h:13,
                 from /kisskb/src/include/linux/serial_sci.h:6,
                 from /kisskb/src/arch/sh/kernel/cpu/sh2/setup-sh7619.c:11:
/kisskb/src/include/linux/sh_intc.h:100:63: warning: division 'sizeof (void *) / sizeof (void)' does not compute the number of array elements [-Wsizeof-pointer-div]
  100 | #define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a)
      |                                                               ^
/kisskb/src/include/linux/sh_intc.h:105:24: note: in expansion of macro '_INTC_ARRAY'
  105 |  _INTC_ARRAY(vectors), _INTC_ARRAY(groups), \
      |                        ^~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:124:8: note: in expansion of macro 'INTC_HW_DESC'
  124 |  .hw = INTC_HW_DESC(vectors, groups, mask_regs,   \
      |        ^~~~~~~~~~~~
/kisskb/src/arch/sh/kernel/cpu/sh2/setup-sh7619.c:58:8: note: in expansion of macro 'DECLARE_INTC_DESC'
   58 | static DECLARE_INTC_DESC(intc_desc, "sh7619", vectors, NULL,
      |        ^~~~~~~~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:100:63: warning: division 'sizeof (void *) / sizeof (void)' does not compute the number of array elements [-Wsizeof-pointer-div]
  100 | #define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a)
      |                                                               ^
/kisskb/src/include/linux/sh_intc.h:106:2: note: in expansion of macro '_INTC_ARRAY'
  106 |  _INTC_ARRAY(mask_regs), _INTC_ARRAY(prio_regs), \
      |  ^~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:124:8: note: in expansion of macro 'INTC_HW_DESC'
  124 |  .hw = INTC_HW_DESC(vectors, groups, mask_regs,   \
      |        ^~~~~~~~~~~~
/kisskb/src/arch/sh/kernel/cpu/sh2/setup-sh7619.c:58:8: note: in expansion of macro 'DECLARE_INTC_DESC'
   58 | static DECLARE_INTC_DESC(intc_desc, "sh7619", vectors, NULL,
      |        ^~~~~~~~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:100:63: warning: division 'sizeof (void *) / sizeof (void)' does not compute the number of array elements [-Wsizeof-pointer-div]
  100 | #define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a)
      |                                                               ^
/kisskb/src/include/linux/sh_intc.h:107:2: note: in expansion of macro '_INTC_ARRAY'
  107 |  _INTC_ARRAY(sense_regs), _INTC_ARRAY(ack_regs), \
      |  ^~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:124:8: note: in expansion of macro 'INTC_HW_DESC'
  124 |  .hw = INTC_HW_DESC(vectors, groups, mask_regs,   \
      |        ^~~~~~~~~~~~
/kisskb/src/arch/sh/kernel/cpu/sh2/setup-sh7619.c:58:8: note: in expansion of macro 'DECLARE_INTC_DESC'
   58 | static DECLARE_INTC_DESC(intc_desc, "sh7619", vectors, NULL,
      |        ^~~~~~~~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:100:63: warning: division 'sizeof (void *) / sizeof (void)' does not compute the number of array elements [-Wsizeof-pointer-div]
  100 | #define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a)
      |                                                               ^
/kisskb/src/include/linux/sh_intc.h:107:27: note: in expansion of macro '_INTC_ARRAY'
  107 |  _INTC_ARRAY(sense_regs), _INTC_ARRAY(ack_regs), \
      |                           ^~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:124:8: note: in expansion of macro 'INTC_HW_DESC'
  124 |  .hw = INTC_HW_DESC(vectors, groups, mask_regs,   \
      |        ^~~~~~~~~~~~
/kisskb/src/arch/sh/kernel/cpu/sh2/setup-sh7619.c:58:8: note: in expansion of macro 'DECLARE_INTC_DESC'
   58 | static DECLARE_INTC_DESC(intc_desc, "sh7619", vectors, NULL,
      |        ^~~~~~~~~~~~~~~~~
/kisskb/src/drivers/tty/serial/sh-sci.c: In function 'sci_remap_port':
/kisskb/src/drivers/tty/serial/sh-sci.c:2677:19: warning: unused variable 'sport' [-Wunused-variable]
 2677 |  struct sci_port *sport = to_sci_port(port);
      |                   ^~~~~
Completed OK
# rm -rf /kisskb/build/linus_se7619_defconfig_sh4-gcc10
# Build took: 0:00:26.703520