# 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/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux-gcc --version
# < /opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux-ld --version
# < git log --format=%s --max-count=1 4df910620bebb5cfe234af16ac8f6474b60215fd
# < make -s -j 48 ARCH=xtensa O=/kisskb/build/linus_xtensa-allmodconfig_xtensa CROSS_COMPILE=/opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux-  allmodconfig
# Added to kconfig CONFIG_BUILD_DOCSRC=n
# Added to kconfig CONFIG_MODULE_SIG=n
# Added to kconfig CONFIG_SAMPLES=n
# < make -s -j 48 ARCH=xtensa O=/kisskb/build/linus_xtensa-allmodconfig_xtensa CROSS_COMPILE=/opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux-  help
# make -s -j 48 ARCH=xtensa O=/kisskb/build/linus_xtensa-allmodconfig_xtensa CROSS_COMPILE=/opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux-  olddefconfig
# make -s -j 48 ARCH=xtensa O=/kisskb/build/linus_xtensa-allmodconfig_xtensa CROSS_COMPILE=/opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux-  
In file included from /kisskb/src/arch/xtensa/include/asm/atomic.h:19:0,
                 from /kisskb/src/include/linux/atomic.h:7,
                 from /kisskb/src/include/linux/page_counter.h:5,
                 from /kisskb/src/mm/memcontrol.c:25:
/kisskb/src/mm/memcontrol.c: In function 'memcg_reparent_objcgs':
/kisskb/src/arch/xtensa/include/asm/cmpxchg.h:173:3: warning: value computed is not used [-Wunused-value]
  ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
   ^
/kisskb/src/mm/memcontrol.c:328:2: note: in expansion of macro 'xchg'
  xchg(&objcg->memcg, parent);
  ^
/kisskb/src/arch/xtensa/include/asm/cmpxchg.h:173:3: warning: value computed is not used [-Wunused-value]
  ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
   ^
/kisskb/src/mm/memcontrol.c:335:3: note: in expansion of macro 'xchg'
   xchg(&iter->memcg, parent);
   ^
/kisskb/src/drivers/input/joystick/analog.c:160:2: warning: #warning Precise timer not defined for this architecture. [-Wcpp]
 #warning Precise timer not defined for this architecture.
  ^
In file included from /kisskb/src/arch/xtensa/include/asm/atomic.h:19:0,
                 from /kisskb/src/include/linux/atomic.h:7,
                 from /kisskb/src/include/asm-generic/bitops/atomic.h:5,
                 from /kisskb/src/arch/xtensa/include/asm/bitops.h:192,
                 from /kisskb/src/include/linux/bitops.h:29,
                 from /kisskb/src/include/linux/bitmap.h:8,
                 from /kisskb/src/include/linux/ethtool.h:16,
                 from /kisskb/src/drivers/net/ethernet/amazon/ena/ena_netdev.c:11:
/kisskb/src/drivers/net/ethernet/amazon/ena/ena_netdev.c: In function 'ena_xdp_exchange_program_rx_in_range':
/kisskb/src/arch/xtensa/include/asm/cmpxchg.h:173:3: warning: value computed is not used [-Wunused-value]
  ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
   ^
/kisskb/src/drivers/net/ethernet/amazon/ena/ena_netdev.c:457:3: note: in expansion of macro 'xchg'
   xchg(&rx_ring->xdp_bpf_prog, prog);
   ^
In file included from /kisskb/src/arch/xtensa/include/asm/atomic.h:19:0,
                 from /kisskb/src/include/linux/atomic.h:7,
                 from /kisskb/src/include/asm-generic/bitops/atomic.h:5,
                 from /kisskb/src/arch/xtensa/include/asm/bitops.h:192,
                 from /kisskb/src/include/linux/bitops.h:29,
                 from /kisskb/src/include/linux/kernel.h:12,
                 from /kisskb/src/include/linux/list.h:9,
                 from /kisskb/src/include/linux/wait.h:7,
                 from /kisskb/src/include/linux/wait_bit.h:8,
                 from /kisskb/src/include/linux/fs.h:6,
                 from /kisskb/src/fs/ocfs2/file.c:13:
/kisskb/src/fs/ocfs2/file.c: In function 'ocfs2_file_write_iter':
/kisskb/src/arch/xtensa/include/asm/cmpxchg.h:173:3: warning: value computed is not used [-Wunused-value]
  ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
   ^
/kisskb/src/fs/ocfs2/file.c:2419:3: note: in expansion of macro 'xchg'
   xchg(&iocb->ki_complete, saved_ki_complete);
   ^
/kisskb/src/drivers/gpu/drm/rockchip/cdn-dp-core.c:1124:12: warning: 'cdn_dp_resume' defined but not used [-Wunused-function]
 static int cdn_dp_resume(struct device *dev)
            ^
In file included from /kisskb/src/arch/xtensa/include/asm/atomic.h:19:0,
                 from /kisskb/src/include/linux/atomic.h:7,
                 from /kisskb/src/include/asm-generic/bitops/atomic.h:5,
                 from /kisskb/src/arch/xtensa/include/asm/bitops.h:192,
                 from /kisskb/src/include/linux/bitops.h:29,
                 from /kisskb/src/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c:11:
/kisskb/src/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c: In function 'ixgbevf_xdp_setup':
/kisskb/src/arch/xtensa/include/asm/cmpxchg.h:173:3: warning: value computed is not used [-Wunused-value]
  ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
   ^
/kisskb/src/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c:4463:4: note: in expansion of macro 'xchg'
    xchg(&adapter->rx_ring[i]->xdp_prog, adapter->xdp_prog);
    ^
WARNING: modpost: lib/test_bitmap.o(.text.unlikely+0x58): Section mismatch in reference from the function bitmap_equal() to the variable .init.rodata:clump_exp
The function bitmap_equal() references
the variable __initconst clump_exp.
This is often because bitmap_equal lacks a __initconst 
annotation or the annotation of clump_exp is wrong.

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x3570): Section mismatch in reference from the variable qed_mfw_legacy_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_legacy_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x3588): Section mismatch in reference from the variable qed_mfw_legacy_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_legacy_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x35a0): Section mismatch in reference from the variable qed_mfw_legacy_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_legacy_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x35b8): Section mismatch in reference from the variable qed_mfw_legacy_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_legacy_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x35d0): Section mismatch in reference from the variable qed_mfw_legacy_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_legacy_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x35e8): Section mismatch in reference from the variable qed_mfw_legacy_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_legacy_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x3600): Section mismatch in reference from the variable qed_mfw_legacy_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_legacy_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x3618): Section mismatch in reference from the variable qed_mfw_ext_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_ext_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x3630): Section mismatch in reference from the variable qed_mfw_ext_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_ext_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x3648): Section mismatch in reference from the variable qed_mfw_ext_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_ext_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x3660): Section mismatch in reference from the variable qed_mfw_ext_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_ext_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x3678): Section mismatch in reference from the variable qed_mfw_ext_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_ext_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x3690): Section mismatch in reference from the variable qed_mfw_ext_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_ext_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x36a8): Section mismatch in reference from the variable qed_mfw_ext_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_ext_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x36c0): Section mismatch in reference from the variable qed_mfw_ext_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_ext_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x36d8): Section mismatch in reference from the variable qed_mfw_ext_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_ext_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qede/qede.o(.data+0x134): Section mismatch in reference from the variable qede_forced_speed_maps to the variable .init.rodata:qede_forced_speed_100000
The variable qede_forced_speed_maps references
the variable __initconst qede_forced_speed_100000
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qede/qede.o(.data+0x14c): Section mismatch in reference from the variable qede_forced_speed_maps to the variable .init.rodata:qede_forced_speed_100000
The variable qede_forced_speed_maps references
the variable __initconst qede_forced_speed_100000
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qede/qede.o(.data+0x164): Section mismatch in reference from the variable qede_forced_speed_maps to the variable .init.rodata:qede_forced_speed_100000
The variable qede_forced_speed_maps references
the variable __initconst qede_forced_speed_100000
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qede/qede.o(.data+0x17c): Section mismatch in reference from the variable qede_forced_speed_maps to the variable .init.rodata:qede_forced_speed_100000
The variable qede_forced_speed_maps references
the variable __initconst qede_forced_speed_100000
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qede/qede.o(.data+0x194): Section mismatch in reference from the variable qede_forced_speed_maps to the variable .init.rodata:qede_forced_speed_100000
The variable qede_forced_speed_maps references
the variable __initconst qede_forced_speed_100000
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qede/qede.o(.data+0x1ac): Section mismatch in reference from the variable qede_forced_speed_maps to the variable .init.rodata:qede_forced_speed_100000
The variable qede_forced_speed_maps references
the variable __initconst qede_forced_speed_100000
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qede/qede.o(.data+0x1c4): Section mismatch in reference from the variable qede_forced_speed_maps to the variable .init.rodata:qede_forced_speed_100000
The variable qede_forced_speed_maps references
the variable __initconst qede_forced_speed_100000
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

Completed OK
# rm -rf /kisskb/build/linus_xtensa-allmodconfig_xtensa
# Build took: 0:15:22.899157