# git rev-parse -q --verify a6fcdbf95d7907bc5d5a669adb86e6bda72d738b^{commit} a6fcdbf95d7907bc5d5a669adb86e6bda72d738b already have revision, skipping fetch # git checkout -q -f -B kisskb a6fcdbf95d7907bc5d5a669adb86e6bda72d738b # git clean -qxdf # < git log -1 # commit a6fcdbf95d7907bc5d5a669adb86e6bda72d738b # Author: Reza Arbab # Date: Thu Aug 2 23:03:36 2018 -0500 # # powerpc/powernv: Fix concurrency issue with npu->mmio_atsd_usage # # We've encountered a performance issue when multiple processors stress # {get,put}_mmio_atsd_reg(). These functions contend for # mmio_atsd_usage, an unsigned long used as a bitmask. # # The accesses to mmio_atsd_usage are done using test_and_set_bit_lock() # and clear_bit_unlock(). As implemented, both of these will require # a (successful) stwcx to that same cache line. # # What we end up with is thread A, attempting to unlock, being slowed by # other threads repeatedly attempting to lock. A's stwcx instructions # fail and retry because the memory reservation is lost every time a # different thread beats it to the punch. # # There may be a long-term way to fix this at a larger scale, but for # now resolve the immediate problem by gating our call to # test_and_set_bit_lock() with one to test_bit(), which is obviously # implemented without using a store. # # Fixes: 1ab66d1fbada ("powerpc/powernv: Introduce address translation services for Nvlink2") # Signed-off-by: Reza Arbab # Acked-by: Alistair Popple # Signed-off-by: Michael Ellerman # < /opt/cross/kisskb/gcc-5.3.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version # < git log --format=%s --max-count=1 a6fcdbf95d7907bc5d5a669adb86e6bda72d738b # < make -s -j 10 ARCH=powerpc O=/kisskb/build/powerpc-next_mpc85xx_smp_defconfig_powerpc-5.3 CROSS_COMPILE=/opt/cross/kisskb/gcc-5.3.0-nolibc/powerpc64-linux/bin/powerpc64-linux- mpc85xx_smp_defconfig # make -s -j 10 ARCH=powerpc O=/kisskb/build/powerpc-next_mpc85xx_smp_defconfig_powerpc-5.3 CROSS_COMPILE=/opt/cross/kisskb/gcc-5.3.0-nolibc/powerpc64-linux/bin/powerpc64-linux- /kisskb/src/net/Makefile:24: CC cannot link executables. Skipping bpfilter. /kisskb/src/net/Makefile:24: CC cannot link executables. Skipping bpfilter. In file included from /kisskb/src/include/linux/kernel.h:10:0, from /kisskb/src/include/linux/list.h:9, from /kisskb/src/include/linux/module.h:9, from /kisskb/src/drivers/net/ethernet/freescale/fs_enet/mac-scc.c:15: /kisskb/src/drivers/net/ethernet/freescale/fs_enet/mac-scc.c: In function 'allocate_bd': /kisskb/src/include/linux/err.h:22:49: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast] #define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO) ^ /kisskb/src/include/linux/compiler.h:77:42: note: in definition of macro 'unlikely' # define unlikely(x) __builtin_expect(!!(x), 0) ^ /kisskb/src/drivers/net/ethernet/freescale/fs_enet/mac-scc.c:139:6: note: in expansion of macro 'IS_ERR_VALUE' if (IS_ERR_VALUE(fep->ring_mem_addr)) ^ arch/powerpc/boot/mpc8541cds.dtb: Warning (pci_device_bus_num): /pci@e0008000/i8259@19000:bus-range: PCI bus number 1 out of range, expected (0 - 0) arch/powerpc/boot/mpc8555cds.dtb: Warning (pci_device_bus_num): /pci@e0008000/i8259@19000:bus-range: PCI bus number 1 out of range, expected (0 - 0) INFO: Uncompressed kernel (size 0xbf36e4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf36e4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf36e4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf36e4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf36e4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf36e4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf36e4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf36e4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf36e4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbe2f2c) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) Image Name: Linux-4.18.0-rc3-ga6fcdbf Created: Fri Aug 3 16:54:07 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5896482 Bytes = 5758.28 kB = 5.62 MB Load Address: 00c00000 Entry Point: 00c0020c Image Name: Linux-4.18.0-rc3-ga6fcdbf Created: Fri Aug 3 16:54:07 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5895250 Bytes = 5757.08 kB = 5.62 MB Load Address: 00c00000 Entry Point: 00c0020c INFO: Uncompressed kernel (size 0xbf36e4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf36e4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) Image Name: Linux-4.18.0-rc3-ga6fcdbf Created: Fri Aug 3 16:54:07 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5896792 Bytes = 5758.59 kB = 5.62 MB Load Address: 00c00000 Entry Point: 00c0020c Image Name: Linux-4.18.0-rc3-ga6fcdbf Created: Fri Aug 3 16:54:07 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5895246 Bytes = 5757.08 kB = 5.62 MB Load Address: 00c00000 Entry Point: 00c0020c Image Name: Linux-4.18.0-rc3-ga6fcdbf Created: Fri Aug 3 16:54:07 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5872379 Bytes = 5734.75 kB = 5.60 MB Load Address: 00000000 Entry Point: 00000000 Image Name: Linux-4.18.0-rc3-ga6fcdbf Created: Fri Aug 3 16:54:07 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5895096 Bytes = 5756.93 kB = 5.62 MB Load Address: 00c00000 Entry Point: 00c00278 Image Name: Linux-4.18.0-rc3-ga6fcdbf Created: Fri Aug 3 16:54:07 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5896227 Bytes = 5758.03 kB = 5.62 MB Load Address: 00c00000 Entry Point: 00c0020c Image Name: Linux-4.18.0-rc3-ga6fcdbf Created: Fri Aug 3 16:54:07 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5896834 Bytes = 5758.63 kB = 5.62 MB Load Address: 00c00000 Entry Point: 00c0020c Image Name: Linux-4.18.0-rc3-ga6fcdbf Created: Fri Aug 3 16:54:07 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5896495 Bytes = 5758.30 kB = 5.62 MB Load Address: 00c00000 Entry Point: 00c0020c Image Name: Linux-4.18.0-rc3-ga6fcdbf Created: Fri Aug 3 16:54:07 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5895567 Bytes = 5757.39 kB = 5.62 MB Load Address: 00c00000 Entry Point: 00c0020c INFO: Uncompressed kernel (size 0xbf36e4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf36e4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf36e4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf36e4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) Image Name: Linux-4.18.0-rc3-ga6fcdbf Created: Fri Aug 3 16:54:10 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5895325 Bytes = 5757.15 kB = 5.62 MB Load Address: 00c00000 Entry Point: 00c0020c Image Name: Linux-4.18.0-rc3-ga6fcdbf Created: Fri Aug 3 16:54:10 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5895305 Bytes = 5757.13 kB = 5.62 MB Load Address: 00c00000 Entry Point: 00c00278 Image Name: Linux-4.18.0-rc3-ga6fcdbf Created: Fri Aug 3 16:54:10 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5896445 Bytes = 5758.25 kB = 5.62 MB Load Address: 00c00000 Entry Point: 00c00278 Image Name: Linux-4.18.0-rc3-ga6fcdbf Created: Fri Aug 3 16:54:10 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5896375 Bytes = 5758.18 kB = 5.62 MB Load Address: 00c00000 Entry Point: 00c00278 Image Name: Linux-4.18.0-rc3-ga6fcdbf Created: Fri Aug 3 16:54:10 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5896447 Bytes = 5758.25 kB = 5.62 MB Load Address: 00c00000 Entry Point: 00c00278 Image Name: Linux-4.18.0-rc3-ga6fcdbf Created: Fri Aug 3 16:54:10 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5895356 Bytes = 5757.18 kB = 5.62 MB Load Address: 00c00000 Entry Point: 00c0020c Completed OK # rm -rf /kisskb/build/powerpc-next_mpc85xx_smp_defconfig_powerpc-5.3 # Build took: 0:02:22.875656