# 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 # 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 # Signed-off-by: Feng Tang # Acked-by: Waiman Long # Signed-off-by: Linus Torvalds # < /opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux-gcc --version # < /opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux-ld --version # < git log --format=%s --max-count=1 4df910620bebb5cfe234af16ac8f6474b60215fd # < make -s -j 48 ARCH=mips O=/kisskb/build/linus_mips-allmodconfig_mipsel CROSS_COMPILE=/opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux- allmodconfig # Added to kconfig CONFIG_BUILD_DOCSRC=n # Added to kconfig CONFIG_MODULE_SIG=n # Added to kconfig CONFIG_SAMPLES=n # Added to kconfig CONFIG_MIPS_CPS_NS16550_BASE=0x1b0003f8 # Added to kconfig CONFIG_MIPS_CPS_NS16550_SHIFT=0 # Added to kconfig # < make -s -j 48 ARCH=mips O=/kisskb/build/linus_mips-allmodconfig_mipsel CROSS_COMPILE=/opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux- help # make -s -j 48 ARCH=mips O=/kisskb/build/linus_mips-allmodconfig_mipsel CROSS_COMPILE=/opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux- olddefconfig .config:12743:warning: override: reassigning to symbol MIPS_CPS_NS16550_SHIFT # make -s -j 48 ARCH=mips O=/kisskb/build/linus_mips-allmodconfig_mipsel CROSS_COMPILE=/opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux- /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/mips/include/asm/sibyte/sb1250.h:28:0, from /kisskb/src/drivers/watchdog/sb_wdog.c:58: /kisskb/src/arch/mips/include/asm/sibyte/bcm1480_scd.h:261:0: warning: "M_SPC_CFG_CLEAR" redefined #define M_SPC_CFG_CLEAR M_BCM1480_SPC_CFG_CLEAR ^ In file included from /kisskb/src/arch/mips/include/asm/sibyte/sb1250.h:27:0, from /kisskb/src/drivers/watchdog/sb_wdog.c:58: /kisskb/src/arch/mips/include/asm/sibyte/sb1250_scd.h:392:0: note: this is the location of the previous definition #define M_SPC_CFG_CLEAR _SB_MAKEMASK1(32) ^ In file included from /kisskb/src/arch/mips/include/asm/sibyte/sb1250.h:28:0, from /kisskb/src/drivers/watchdog/sb_wdog.c:58: /kisskb/src/arch/mips/include/asm/sibyte/bcm1480_scd.h:262:0: warning: "M_SPC_CFG_ENABLE" redefined #define M_SPC_CFG_ENABLE M_BCM1480_SPC_CFG_ENABLE ^ In file included from /kisskb/src/arch/mips/include/asm/sibyte/sb1250.h:27:0, from /kisskb/src/drivers/watchdog/sb_wdog.c:58: /kisskb/src/arch/mips/include/asm/sibyte/sb1250_scd.h:393:0: note: this is the location of the previous definition #define M_SPC_CFG_ENABLE _SB_MAKEMASK1(33) ^ FIT description: Linux 5.10.0-rc5+ Created: Fri Nov 27 06:31:28 2020 Image 0 (kernel@0) Description: Linux 5.10.0-rc5+ Created: Fri Nov 27 06:31:28 2020 Type: Kernel Image Compression: gzip compressed Data Size: 8304145 Bytes = 8109.52 KiB = 7.92 MiB Architecture: MIPS OS: Linux Load Address: 0x84000000 Entry Point: 0x84ca4600 Hash algo: sha1 Hash value: 340af05c027dfab20d1db3d15ab9987efd8eb175 Image 1 (fdt@boston) Description: img,boston Device Tree Created: Fri Nov 27 06:31:28 2020 Type: Flat Device Tree Compression: uncompressed Data Size: 3793 Bytes = 3.70 KiB = 0.00 MiB Architecture: MIPS Hash algo: sha1 Hash value: 4799f50d688573234da6e9d7701234d394759ef4 Image 2 (fdt@ni169445) Description: NI 169445 device tree Created: Fri Nov 27 06:31:28 2020 Type: Flat Device Tree Compression: uncompressed Data Size: 1871 Bytes = 1.83 KiB = 0.00 MiB Architecture: MIPS Hash algo: sha1 Hash value: 51b89b31605ee62038c8468c429af091dfc75ec7 Image 3 (fdt@ocelot_pcb123) Description: MSCC Ocelot PCB123 Device Tree Created: Fri Nov 27 06:31:28 2020 Type: Flat Device Tree Compression: uncompressed Data Size: 4659 Bytes = 4.55 KiB = 0.00 MiB Architecture: MIPS Hash algo: sha1 Hash value: 5bcb6e4f21e8e5372544aa130b3bd097355a9050 Image 4 (fdt@ocelot_pcb120) Description: MSCC Ocelot PCB120 Device Tree Created: Fri Nov 27 06:31:28 2020 Type: Flat Device Tree Compression: uncompressed Data Size: 5418 Bytes = 5.29 KiB = 0.01 MiB Architecture: MIPS Hash algo: sha1 Hash value: 93d882f2009a217e0fa9dab94788535ed2be8476 Image 5 (fdt@xilfpga) Description: MIPSfpga (xilfpga) Device Tree Created: Fri Nov 27 06:31:28 2020 Type: Flat Device Tree Compression: uncompressed Data Size: 2708 Bytes = 2.64 KiB = 0.00 MiB Architecture: MIPS Hash algo: sha1 Hash value: 63d058b780f65e22da30f0a183433765f1807f1d Default Configuration: 'conf@default' Configuration 0 (conf@default) Description: Generic Linux kernel Kernel: kernel@0 Configuration 1 (conf@boston) Description: Boston Linux kernel Kernel: kernel@0 FDT: fdt@boston Configuration 2 (conf@ni169445) Description: NI 169445 Linux Kernel Kernel: kernel@0 FDT: fdt@ni169445 Configuration 3 (conf@ocelot_pcb123) Description: Ocelot Linux kernel Kernel: kernel@0 FDT: fdt@ocelot_pcb123 Configuration 4 (conf@ocelot_pcb120) Description: Ocelot Linux kernel Kernel: kernel@0 FDT: fdt@ocelot_pcb120 Configuration 5 (conf@xilfpga) Description: MIPSfpga Linux kernel Kernel: kernel@0 FDT: fdt@xilfpga Completed OK # rm -rf /kisskb/build/linus_mips-allmodconfig_mipsel # Build took: 0:20:12.521013