Hi Mel, On Fri, May 20, 2016 at 7:42 PM, Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx> wrote: > Web: https://git.kernel.org/torvalds/c/c33d6c06f60f710f0305ae792773e1c2560e1e51 > Commit: c33d6c06f60f710f0305ae792773e1c2560e1e51 > Parent: 48ee5f3696f62496481a8b6d852bcad9b3ebbe37 > Refname: refs/heads/master > Author: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> > AuthorDate: Thu May 19 17:14:10 2016 -0700 > Committer: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > CommitDate: Thu May 19 19:12:14 2016 -0700 > > mm, page_alloc: avoid looking up the first zone in a zonelist twice > > The allocator fast path looks up the first usable zone in a zonelist and > then get_page_from_freelist does the same job in the zonelist iterator. > This patch preserves the necessary information. > > 4.6.0-rc2 4.6.0-rc2 > fastmark-v1r20 initonce-v1r20 > Min alloc-odr0-1 364.00 ( 0.00%) 359.00 ( 1.37%) > Min alloc-odr0-2 262.00 ( 0.00%) 260.00 ( 0.76%) > Min alloc-odr0-4 214.00 ( 0.00%) 214.00 ( 0.00%) > Min alloc-odr0-8 186.00 ( 0.00%) 186.00 ( 0.00%) > Min alloc-odr0-16 173.00 ( 0.00%) 173.00 ( 0.00%) > Min alloc-odr0-32 165.00 ( 0.00%) 165.00 ( 0.00%) > Min alloc-odr0-64 161.00 ( 0.00%) 162.00 ( -0.62%) > Min alloc-odr0-128 159.00 ( 0.00%) 161.00 ( -1.26%) > Min alloc-odr0-256 168.00 ( 0.00%) 170.00 ( -1.19%) > Min alloc-odr0-512 180.00 ( 0.00%) 181.00 ( -0.56%) > Min alloc-odr0-1024 190.00 ( 0.00%) 190.00 ( 0.00%) > Min alloc-odr0-2048 196.00 ( 0.00%) 196.00 ( 0.00%) > Min alloc-odr0-4096 202.00 ( 0.00%) 202.00 ( 0.00%) > Min alloc-odr0-8192 206.00 ( 0.00%) 205.00 ( 0.49%) > Min alloc-odr0-16384 206.00 ( 0.00%) 205.00 ( 0.49%) > > The benefit is negligible and the results are within the noise but each > cycle counts. > > Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> > Cc: Vlastimil Babka <vbabka@xxxxxxx> > Cc: Jesper Dangaard Brouer <brouer@xxxxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> About one week ago, I started seeing an obscure intermittent crash during system shutdown on m68k/ARAnyM using atari_defconfig. The crash isn't 100% reproducible, but it happens during ca. 1 out of 5 shutdowns. I finally managed to bisect it to the above commit. I did verify that the parent commit didn't crash after 60 tries. Unfortunately I couldn't revert the offending commit on top of v4.7-rc1, due to conflicting changes. Do you have any idea what's going wrong? Thanks! Linux version 4.6.0-atari-05133-gc33d6c06f60f710f (geert@ramsan) (gcc version 4.1.2 20061115 (prerelease) (Ubuntu 4.1.1-21)) #364 Mon May 30 14:13:39 CEST 2016 Saving 198 bytes of bootinfo console [debug0] enabled Atari hardware found: VIDEL STDMA-SCSI ST_MFP YM2149 PCM CODEC DSP56K SCC ANALOG_JOY Blitter tried to read byte from register ff8a00 at 007606 BLITTER IDE TT_CLK FDC_SPEED On node 0 totalpages: 3584 free_area_init_node: node 0, pgdat 003ca184, node_mem_map 0046a000 DMA zone: 32 pages used for memmap DMA zone: 0 pages reserved DMA zone: 3584 pages, LIFO batch:0 On node 1 totalpages: 65536 free_area_init_node: node 1, pgdat 003caa76, node_mem_map 0048e090 DMA zone: 576 pages used for memmap DMA zone: 0 pages reserved DMA zone: 65536 pages, LIFO batch:15 NatFeats found (ARAnyM, 1.0) pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768 pcpu-alloc: [0] 0 Built 2 zonelists in Zone order, mobility grouping on. Total pages: 68512 Kernel command line: root=/dev/hda1 video=atafb:tthigh debug=par console=tty0 initcall_blacklist=atari_scsi_driver_init BOOT_IMAGE=vmlinux blacklisting initcall atari_scsi_driver_init PID hash table entries: 2048 (order: 1, 8192 bytes) Dentry cache hash table entries: 65536 (order: 6, 262144 bytes) Inode-cache hash table entries: 32768 (order: 5, 131072 bytes) Sorting __ex_table... Memory: 268060K/276480K available (3023K kernel code, 301K rwdata, 716K rodata, 148K init, 178K bss, 8420K reserved, 0K cma-reserved) Virtual kernel memory layout: vector : 0x003c9c74 - 0x003ca074 ( 1 KiB) kmap : 0xd0000000 - 0xf0000000 ( 512 MiB) vmalloc : 0x11800000 - 0xd0000000 (3048 MiB) lowmem : 0x00000000 - 0x11000000 ( 272 MiB) .init : 0x003f7000 - 0x0041c000 ( 148 KiB) .text : 0x00001000 - 0x002f4fc6 (3024 KiB) .data : 0x002f7e20 - 0x003f65f0 (1018 KiB) .bss : 0x003c9b80 - 0x003f65f0 ( 179 KiB) NR_IRQS:141 Console: colour dummy device 80x25 console [tty0] enabled Calibrating delay loop... 187.80 BogoMIPS (lpj=939008) pid_max: default: 32768 minimum: 301 Mount-cache hash table entries: 1024 (order: 0, 4096 bytes) Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes) devtmpfs: initialized clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns NET: Registered protocol family 16 SCSI subsystem initialized VFS: Disk quotas dquot_6.6.0 VFS: Dquot-cache hash table entries: 1024 (order 0, 4096 bytes) NET: Registered protocol family 2 TCP established hash table entries: 4096 (order: 2, 16384 bytes) TCP bind hash table entries: 4096 (order: 2, 16384 bytes) TCP: Hash tables configured (established 4096 bind 4096) UDP hash table entries: 256 (order: 0, 4096 bytes) UDP-Lite hash table entries: 256 (order: 0, 4096 bytes) NET: Registered protocol family 1 RPC: Registered named UNIX socket transport module. RPC: Registered udp transport module. RPC: Registered tcp transport module. RPC: Registered tcp NFSv4.1 backchannel transport module. nfhd8: found device with 2118816 blocks (512 bytes) nfhd8: AHDI p1 p2 nfeth: API 5 eth0: nfeth addr:192.168.0.1 (192.168.0.2) HWaddr:00:41:45:54:48:30 futex hash table entries: 256 (order: -1, 3072 bytes) workingset: timestamp_bits=25 max_order=17 bucket_order=0 Block layer SCSI generic (bsg) driver version 0.4 loaded (major 252) io scheduler noop registered io scheduler cfq registered (default) atafb_init: start atafb_init: initializing Falcon hw atafb: screen_base 006cf000 phys_screen_base 6cf000 screen_len 311296 Determined 640x480, depth 4 virtual 640x972 Console: switching to colour frame buffer device 80x30 fb0: frame buffer device, using 304K of video memory Non-volatile memory driver v1.3 Atari floppy driver: max. HD, track buffering Probing floppy drive(s): fd0 brd: module loaded loop: module loaded Uniform Multi-Platform E-IDE driver ide: Falcon IDE controller Probing IDE interface ide0... hda: Sarge m68k, ATA DISK drive ide0 at 0xfff00000 on irq 15 (serialized) ide-gd driver 1.18 hda: max request size: 128KiB hda: 2118816 sectors (1084 MB) w/256KiB Cache, CHS=2102/16/63 hda: AHDI hda1 hda2 ide-cd driver 5.00 initcall atari_scsi_driver_init blacklisted ne ne (unnamed net_device) (uninitialized): NE*000 ethercard probe at 0x300: not found (no reset ack). ne ne (unnamed net_device) (uninitialized): ne.c: No NE*000 card found at i/o = 0x300 mousedev: PS/2 mouse device common for all mice input: Atari Keyboard as /devices/virtual/input/input0 NET: Registered protocol family 17 NET: Registered protocol family 15 Key type dns_resolver registered hctosys: unable to open rtc device (rtc0) EXT4-fs (hda1): mounting ext3 file system using the ext4 subsystem EXT4-fs (hda1): mounted filesystem with ordered data mode. Opts: (null) VFS: Mounted root (ext3 filesystem) readonly on device 3:1. devtmpfs: mounted Freeing unused kernel memory: 148K (003f7000 - 0041c000) This architecture does not have kernel memory protection. random: nonblocking pool is initialized Detected scancode offset = 8 (key: 'left ctrl' with scancode $25) Adding 137800k swap on /dev/hda2. Priority:-1 extents:1 across:137800k EXT4-fs (hda1): re-mounted. Opts: EXT4-fs (hda1): re-mounted. Opts: errors=remount-ro BUG: scheduling while atomic: cron/668/0x10c9a0c0 Modules linked in: CPU: 0 PID: 668 Comm: cron Not tainted 4.6.0-atari-05133-gc33d6c06f60f710f #364 Stack from 10c9a074: 10c9a074 003763ca 0003d7d0 00361a58 00bcf834 0000029c 10c9a0c0 10c9a0c0 002f0f42 00bcf5e0 00000000 00000082 0048e018 00000000 00000000 002f0c30 000410de 00000000 00000000 10c9a0e0 002f112c 00000000 7fffffff 10c9a180 003b1490 00bcf60c 10c9a1f0 10c9a118 002f2d30 00000000 10c9a174 10c9a180 0003ef56 003b1490 00bcf60c 003b1490 00bcf60c 0003eff6 003b1490 00bcf60c 003b1490 10c9a128 002f118e 7fffffff 00000082 002f1612 002f1624 7fffffff Call Trace: [<0003d7d0>] __schedule_bug+0x40/0x54 [<002f0f42>] __schedule+0x312/0x388 [<002f0c30>] __schedule+0x0/0x388 [<000410de>] prepare_to_wait+0x0/0x52 [<002f112c>] schedule+0x64/0x82 [<002f2d30>] schedule_timeout+0xda/0x104 [<0003ef56>] set_next_entity+0x18/0x40 [<0003eff6>] pick_next_task_fair+0x78/0xda [<002f118e>] io_schedule_timeout+0x36/0x4a [<002f1612>] bit_wait_io+0x0/0x40 [<002f1624>] bit_wait_io+0x12/0x40 [<002f12c4>] __wait_on_bit+0x46/0x76 [<0006a06a>] wait_on_page_bit_killable+0x64/0x6c [<002f1612>] bit_wait_io+0x0/0x40 [<000411fe>] wake_bit_function+0x0/0x4e [<0006a1b8>] __lock_page_or_retry+0xde/0x124 [<00217000>] do_scan_async+0x114/0x17c [<00098856>] lookup_swap_cache+0x24/0x4e [<0008b7c8>] handle_mm_fault+0x626/0x7de [<0008ef46>] find_vma+0x0/0x66 [<002f2612>] down_read+0x0/0xe [<0006a001>] wait_on_page_bit_killable_timeout+0x77/0x7c [<0008ef5c>] find_vma+0x16/0x66 [<00006b44>] do_page_fault+0xe6/0x23a [<0000c350>] res_func+0xa3c/0x141a [<00005bb8>] buserr_c+0x190/0x6d4 [<0000c350>] res_func+0xa3c/0x141a [<000028ec>] buserr+0x20/0x28 [<0000c350>] res_func+0xa3c/0x141a [<000028ec>] buserr+0x20/0x28 ... Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>