1. 06 May, 2019 15 commits
  2. 05 May, 2019 1 commit
    • Richard Weinberger's avatar
      Merge tag 'nand/for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux into mtd/next · 1c7cbd63
      Richard Weinberger authored
      NAND core changes:
      - Support having the bad block markers in either the first, second or
        last page of a block. The combination of all three location is now
        possible.
      - Constification of NAND_OP_PARSER(_PATTERN) elements.
      - Generic NAND DT bindings changed to yaml format (can be used to
        check the proposed bindings. First platform to be fully supported:
        sunxi.
      - Stopped using several legacy hooks.
      - Preparation to use the generic NAND layer with the addition of
        several helpers and the removal of the struct nand_chip from generic
        functions.
      - Kconfig cleanup to prepare the introduction of external ECC engines
        support.
      - Fallthrough comments.
      - Introduction of the SPI-mem dirmap API for SPI-NAND devices.
      
      Raw NAND controller drivers changes:
      - nandsim:
        * Switch to ->exec-op().
      - meson:
        * Misc cleanups and fixes.
        * New OOB layout.
      - Sunxi:
        * A23/A33 NAND DMA support.
      - Ingenic:
        * Full reorganization and cleanup.
        * Clear separation between NAND controller and ECC engine.
        * Support JZ4740 an JZ4725B.
      - Denali:
        * Clear controller/chip separation.
        * ->exec_op() migration.
        * Various cleanups.
      - fsl_elbc:
        * Enable software ECC support.
      - Atmel:
        * Sam9x60 support.
      - GPMI:
        * Introduce the GPMI_IS_MXS() macro.
      - Various trivial/spelling/coding style fixes.
      1c7cbd63
  3. 29 Apr, 2019 1 commit
  4. 28 Apr, 2019 5 commits
    • Linus Torvalds's avatar
      Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm · 9520b532
      Linus Torvalds authored
      Pull ARM fixes from Russell King:
       "A small number of ARM fixes
      
         - Fix function tracer and unwinder dependencies so that we don't end
           up building kernels that will crash
      
         - Fix ARMv7M nommu initialisation (missing register initialisation)
      
         - Fix EFI decompressor entry (ensuring barrier instructions are
           enabled prior to use)"
      
      * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
        ARM: 8857/1: efi: enable CP15 DMB instructions before cleaning the cache
        ARM: 8856/1: NOMMU: Fix CCR register faulty initialization when MPU is disabled
        ARM: fix function graph tracer and unwinder dependencies
      9520b532
    • Linus Torvalds's avatar
      Merge tag 'powerpc-5.1-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux · 0d82044e
      Linus Torvalds authored
      Pull powerpc fixes from Michael Ellerman:
       "A one-liner to make our Radix MMU support depend on HUGETLB_PAGE. We
        use some of the hugetlb inlines (eg. pud_huge()) when operating on the
        linear mapping and if they're compiled into empty wrappers we can
        corrupt memory.
      
        Then two fixes to our VFIO IOMMU code. The first is not a regression
        but fixes the locking to avoid a user-triggerable deadlock.
      
        The second does fix a regression since rc1, and depends on the first
        fix. It makes it possible to run guests with large amounts of memory
        again (~256GB).
      
        Thanks to Alexey Kardashevskiy"
      
      * tag 'powerpc-5.1-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
        powerpc/mm_iommu: Allow pinning large regions
        powerpc/mm_iommu: Fix potential deadlock
        powerpc/mm/radix: Make Radix require HUGETLB_PAGE
      0d82044e
    • Linus Torvalds's avatar
      Merge tag 'for-linus-20190428' of git://git.kernel.dk/linux-block · 975a0f40
      Linus Torvalds authored
      Pull block fixes from Jens Axboe:
       "A set of io_uring fixes that should go into this release. In
        particular, this contains:
      
         - The mutex lock vs ctx ref count fix (me)
      
         - Removal of a dead variable (me)
      
         - Two race fixes (Stefan)
      
         - Ring head/tail condition fix for poll full SQ detection (Stefan)"
      
      * tag 'for-linus-20190428' of git://git.kernel.dk/linux-block:
        io_uring: remove 'state' argument from io_{read,write} path
        io_uring: fix poll full SQ detection
        io_uring: fix race condition when sq threads goes sleeping
        io_uring: fix race condition reading SQ entries
        io_uring: fail io_uring_register(2) on a dying io_uring instance
      975a0f40
    • Linus Torvalds's avatar
      Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma · 14f974d7
      Linus Torvalds authored
      Pull rdma fixes from Jason Gunthorpe:
       "One core bug fix and a few driver ones
      
         - FRWR memory registration for hfi1/qib didn't work with with some
           iovas causing a NFSoRDMA failure regression due to a fix in the NFS
           side
      
         - A command flow error in mlx5 allowed user space to send a corrupt
           command (and also smash the kernel stack we've since learned)
      
         - Fix a regression and some bugs with device hot unplug that was
           discovered while reviewing Andrea's patches
      
         - hns has a failure if the user asks for certain QP configurations"
      
      * tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
        RDMA/hns: Bugfix for mapping user db
        RDMA/ucontext: Fix regression with disassociate
        RDMA/mlx5: Use rdma_user_map_io for mapping BAR pages
        RDMA/mlx5: Do not allow the user to write to the clock page
        IB/mlx5: Fix scatter to CQE in DCT QP creation
        IB/rdmavt: Fix frwr memory registration
      14f974d7
    • Linus Torvalds's avatar
      Merge tag 'dmaengine-fix-5.1-rc7' of git://git.infradead.org/users/vkoul/slave-dma · 72a6e35d
      Linus Torvalds authored
      Pull dmaengine fixes from Vinod Koul:
      
       - fix for wrong register use in mediatek driver
      
       - fix in sh driver for glitch is tx_status and treating 0 a valid
         residue for cyclic
      
       - fix in bcm driver for using right memory allocation flag
      
      * tag 'dmaengine-fix-5.1-rc7' of git://git.infradead.org/users/vkoul/slave-dma:
        dmaengine: mediatek-cqdma: fix wrong register usage in mtk_cqdma_start
        dmaengine: sh: rcar-dmac: Fix glitch in dmaengine_tx_status
        dmaengine: sh: rcar-dmac: With cyclic DMA residue 0 is valid
        dmaengine: bcm2835: Avoid GFP_KERNEL in device_prep_slave_sg
      72a6e35d
  5. 27 Apr, 2019 7 commits
  6. 26 Apr, 2019 11 commits
    • Linus Torvalds's avatar
      Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux · 857e17c2
      Linus Torvalds authored
      Pull arm64 fixes from Catalin Marinas:
      
       - keep the tail of an unaligned initrd reserved
      
       - adjust ftrace_make_call() to deal with the relative nature of PLTs
      
      * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
        arm64/module: ftrace: deal with place relative nature of PLTs
        arm64: mm: Ensure tail of unaligned initrd is reserved
      857e17c2
    • Linus Torvalds's avatar
      Merge tag 'trace-v5.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace · e9e1a2e7
      Linus Torvalds authored
      Pull tracing fixes from Steven Rostedt:
       "Three tracing fixes:
      
         - Use "nosteal" for ring buffer splice pages
      
         - Memory leak fix in error path of trace_pid_write()
      
         - Fix preempt_enable_no_resched() (use preempt_enable()) in ring
           buffer code"
      
      * tag 'trace-v5.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
        trace: Fix preempt_enable_no_resched() abuse
        tracing: Fix a memory leak by early error exit in trace_pid_write()
        tracing: Fix buffer_ref pipe ops
      e9e1a2e7
    • Linus Torvalds's avatar
      Merge tag 'gpio-v5.1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio · 29279d21
      Linus Torvalds authored
      Pull GPIO fixes from Linus Walleij:
       "Not much to say about them, regular fixes:
      
         - Fix a bug on the errorpath of gpiochip_add_data_with_key()
      
         - IRQ type setting on the spreadtrum GPIO driver"
      
      * tag 'gpio-v5.1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
        gpio: Fix gpiochip_add_data_with_key() error path
        gpio: eic: sprd: Fix incorrect irq type setting for the sync EIC
      29279d21
    • Linus Torvalds's avatar
      Merge tag 'drm-fixes-2019-04-26' of git://anongit.freedesktop.org/drm/drm · 4e40f0f3
      Linus Torvalds authored
      Pull drm fixes from Dave Airlie:
       "Regular drm fixes, nothing too outstanding, I'm guessing Easter was
        slowing people down.
      
        i915:
         - FEC enable fix
         - BXT display lanes fix
      
        ttm:
         - fix reinit for reloading drivers regression
      
        imx:
         - DP CSC fix
      
        sun4i:
         - module unload/load fix
      
        vc4:
         - memory leak fix
         - compile fix
      
        dw-hdmi:
         - rockchip scdc overflow fix
      
        sched:
         - docs fix
      
        vmwgfx:
         - dma api layering fix"
      
      * tag 'drm-fixes-2019-04-26' of git://anongit.freedesktop.org/drm/drm:
        drm/bridge: dw-hdmi: fix SCDC configuration for ddc-i2c-bus
        drm/vmwgfx: Fix dma API layer violation
        drm/vc4: Fix compilation error reported by kbuild test bot
        drm/sun4i: Unbind components before releasing DRM and memory
        drm/vc4: Fix memory leak during gpu reset.
        drm/sched: Fix description of drm_sched_stop
        drm/imx: don't skip DP channel disable for background plane
        gpu: ipu-v3: dp: fix CSC handling
        drm/ttm: fix re-init of global structures
        drm/sun4i: Fix component unbinding and component master deletion
        drm/sun4i: Set device driver data at bind time for use in unbind
        drm/sun4i: Add missing drm_atomic_helper_shutdown at driver unbind
        drm/i915: Restore correct bxt_ddi_phy_calc_lane_lat_optim_mask() calculation
        drm/i915: Do not enable FEC without DSC
        drm: bridge: dw-hdmi: Fix overflow workaround for Rockchip SoCs
      4e40f0f3
    • Linus Torvalds's avatar
      Merge tag 'for-5.1-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux · d0473f97
      Linus Torvalds authored
      Pull btrfs fix from David Sterba:
       "One patch to fix a crash in io submission path, due to memory
        allocation errors.
      
        In short, the multipage bio work that landed in 5.1 caused larger bios
        that in turn require larger temporary memory for checksums. The patch
        is a workaround, we're going to rework the allocation so it does not
        require the vmalloc fallback.
      
        It took a while to identify that it's caused by patches in 5.1 and not
        a patchset that did some changes in error handling in the code. I've
        tested it on various memory/cpu combinations, it could hit OOM but
        does not crash.
      
        The timestamp of the patch is less than a day due to updates in the
        changelog, tests were running meanwhile"
      
      * tag 'for-5.1-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
        btrfs: Switch memory allocations in async csum calculation path to kvmalloc
      d0473f97
    • Linus Torvalds's avatar
      Merge tag '5.1-rc6-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6 · 58130235
      Linus Torvalds authored
      Pull cifs fixes from Steve French:
       "Three small SMB3 fixes (all for stable as well): two leaks and a
        rename bug"
      
      * tag '5.1-rc6-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
        cifs: fix page reference leak with readv/writev
        cifs: do not attempt cifs operation on smb2+ rename error
        cifs: fix memory leak in SMB2_read
      58130235
    • YueHaibing's avatar
      fs/proc/proc_sysctl.c: Fix a NULL pointer dereference · 89189557
      YueHaibing authored
      Syzkaller report this:
      
        sysctl could not get directory: /net//bridge -12
        kasan: CONFIG_KASAN_INLINE enabled
        kasan: GPF could be caused by NULL-ptr deref or user memory access
        general protection fault: 0000 [#1] SMP KASAN PTI
        CPU: 1 PID: 7027 Comm: syz-executor.0 Tainted: G         C        5.1.0-rc3+ #8
        Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
        RIP: 0010:__write_once_size include/linux/compiler.h:220 [inline]
        RIP: 0010:__rb_change_child include/linux/rbtree_augmented.h:144 [inline]
        RIP: 0010:__rb_erase_augmented include/linux/rbtree_augmented.h:186 [inline]
        RIP: 0010:rb_erase+0x5f4/0x19f0 lib/rbtree.c:459
        Code: 00 0f 85 60 13 00 00 48 89 1a 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f c3 48 89 f2 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 75 0c 00 00 4d 85 ed 4c 89 2e 74 ce 4c 89 ea 48
        RSP: 0018:ffff8881bb507778 EFLAGS: 00010206
        RAX: dffffc0000000000 RBX: ffff8881f224b5b8 RCX: ffffffff818f3f6a
        RDX: 000000000000000a RSI: 0000000000000050 RDI: ffff8881f224b568
        RBP: 0000000000000000 R08: ffffed10376a0ef4 R09: ffffed10376a0ef4
        R10: 0000000000000001 R11: ffffed10376a0ef4 R12: ffff8881f224b558
        R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
        FS:  00007f3e7ce13700(0000) GS:ffff8881f7300000(0000) knlGS:0000000000000000
        CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
        CR2: 00007fd60fbe9398 CR3: 00000001cb55c001 CR4: 00000000007606e0
        DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
        DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
        PKRU: 55555554
        Call Trace:
         erase_entry fs/proc/proc_sysctl.c:178 [inline]
         erase_header+0xe3/0x160 fs/proc/proc_sysctl.c:207
         start_unregistering fs/proc/proc_sysctl.c:331 [inline]
         drop_sysctl_table+0x558/0x880 fs/proc/proc_sysctl.c:1631
         get_subdir fs/proc/proc_sysctl.c:1022 [inline]
         __register_sysctl_table+0xd65/0x1090 fs/proc/proc_sysctl.c:1335
         br_netfilter_init+0x68/0x1000 [br_netfilter]
         do_one_initcall+0xbc/0x47d init/main.c:901
         do_init_module+0x1b5/0x547 kernel/module.c:3456
         load_module+0x6405/0x8c10 kernel/module.c:3804
         __do_sys_finit_module+0x162/0x190 kernel/module.c:3898
         do_syscall_64+0x9f/0x450 arch/x86/entry/common.c:290
         entry_SYSCALL_64_after_hwframe+0x49/0xbe
        Modules linked in: br_netfilter(+) backlight comedi(C) hid_sensor_hub max3100 ti_ads8688 udc_core fddi snd_mona leds_gpio rc_streamzap mtd pata_netcell nf_log_common rc_winfast udp_tunnel snd_usbmidi_lib snd_usb_toneport snd_usb_line6 snd_rawmidi snd_seq_device snd_hwdep videobuf2_v4l2 videobuf2_common videodev media videobuf2_vmalloc videobuf2_memops rc_gadmei_rm008z 8250_of smm665 hid_tmff hid_saitek hwmon_vid rc_ati_tv_wonder_hd_600 rc_core pata_pdc202xx_old dn_rtmsg as3722 ad714x_i2c ad714x snd_soc_cs4265 hid_kensington panel_ilitek_ili9322 drm drm_panel_orientation_quirks ipack cdc_phonet usbcore phonet hid_jabra hid extcon_arizona can_dev industrialio_triggered_buffer kfifo_buf industrialio adm1031 i2c_mux_ltc4306 i2c_mux ipmi_msghandler mlxsw_core snd_soc_cs35l34 snd_soc_core snd_pcm_dmaengine snd_pcm snd_timer ac97_bus snd_compress snd soundcore gpio_da9055 uio ecdh_generic mdio_thunder of_mdio fixed_phy libphy mdio_cavium iptable_security iptable_raw iptable_mangle
         iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_filter bpfilter ip6_vti ip_vti ip_gre ipip sit tunnel4 ip_tunnel hsr veth netdevsim vxcan batman_adv cfg80211 rfkill chnl_net caif nlmon dummy team bonding vcan bridge stp llc ip6_gre gre ip6_tunnel tunnel6 tun joydev mousedev ppdev tpm kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel ide_pci_generic piix aes_x86_64 crypto_simd cryptd ide_core glue_helper input_leds psmouse intel_agp intel_gtt serio_raw ata_generic i2c_piix4 agpgart pata_acpi parport_pc parport floppy rtc_cmos sch_fq_codel ip_tables x_tables sha1_ssse3 sha1_generic ipv6 [last unloaded: br_netfilter]
        Dumping ftrace buffer:
           (ftrace buffer empty)
        ---[ end trace 68741688d5fbfe85 ]---
      
      commit 23da9588 ("fs/proc/proc_sysctl.c: fix NULL pointer
      dereference in put_links") forgot to handle start_unregistering() case,
      while header->parent is NULL, it calls erase_header() and as seen in the
      above syzkaller call trace, accessing &header->parent->root will trigger
      a NULL pointer dereference.
      
      As that commit explained, there is also no need to call
      start_unregistering() if header->parent is NULL.
      
      Link: http://lkml.kernel.org/r/20190409153622.28112-1-yuehaibing@huawei.com
      Fixes: 23da9588 ("fs/proc/proc_sysctl.c: fix NULL pointer dereference in put_links")
      Fixes: 0e47c99d ("sysctl: Replace root_list with links between sysctl_table_sets")
      Signed-off-by: default avatarYueHaibing <yuehaibing@huawei.com>
      Reported-by: default avatarHulk Robot <hulkci@huawei.com>
      Reviewed-by: default avatarKees Cook <keescook@chromium.org>
      Cc: Luis Chamberlain <mcgrof@kernel.org>
      Cc: Alexey Dobriyan <adobriyan@gmail.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      89189557
    • Andrey Ryabinin's avatar
      mm/page_alloc.c: fix never set ALLOC_NOFRAGMENT flag · 8118b82e
      Andrey Ryabinin authored
      Commit 0a79cdad ("mm: use alloc_flags to record if kswapd can wake")
      removed setting of the ALLOC_NOFRAGMENT flag.  Bring it back.
      
      The runtime effect is that ALLOC_NOFRAGMENT behaviour is restored so
      that allocations are spread across local zones to avoid fragmentation
      due to mixing pageblocks as long as possible.
      
      Link: http://lkml.kernel.org/r/20190423120806.3503-2-aryabinin@virtuozzo.com
      Fixes: 0a79cdad ("mm: use alloc_flags to record if kswapd can wake")
      Signed-off-by: default avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
      Acked-by: default avatarMel Gorman <mgorman@techsingularity.net>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8118b82e
    • Andrey Ryabinin's avatar
      mm/page_alloc.c: avoid potential NULL pointer dereference · 8139ad04
      Andrey Ryabinin authored
      ac.preferred_zoneref->zone passed to alloc_flags_nofragment() can be NULL.
      'zone' pointer unconditionally derefernced in alloc_flags_nofragment().
      Bail out on NULL zone to avoid potential crash.  Currently we don't see
      any crashes only because alloc_flags_nofragment() has another bug which
      allows compiler to optimize away all accesses to 'zone'.
      
      Link: http://lkml.kernel.org/r/20190423120806.3503-1-aryabinin@virtuozzo.com
      Fixes: 6bb15450 ("mm, page_alloc: spread allocations across zones before introducing fragmentation")
      Signed-off-by: default avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
      Acked-by: default avatarMel Gorman <mgorman@techsingularity.net>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8139ad04
    • Mel Gorman's avatar
      mm, page_alloc: always use a captured page regardless of compaction result · ee8ab0ee
      Mel Gorman authored
      During the development of commit 5e1f0f09 ("mm, compaction: capture
      a page under direct compaction"), a paranoid check was added to ensure
      that if a captured page was available after compaction that it was
      consistent with the final state of compaction.  The intent was to catch
      serious programming bugs such as using a stale page pointer and causing
      corruption problems.
      
      However, it is possible to get a captured page even if compaction was
      unsuccessful if an interrupt triggered and happened to free pages in
      interrupt context that got merged into a suitable high-order page.  It's
      highly unlikely but Li Wang did report the following warning on s390
      occuring when testing OOM handling.  Note that the warning is slightly
      edited for clarity.
      
        WARNING: CPU: 0 PID: 9783 at mm/page_alloc.c:3777 __alloc_pages_direct_compact+0x182/0x190
        Modules linked in: rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs
          lockd grace fscache sunrpc pkey ghash_s390 prng xts aes_s390
          des_s390 des_generic sha512_s390 zcrypt_cex4 zcrypt vmur binfmt_misc
          ip_tables xfs libcrc32c dasd_fba_mod qeth_l2 dasd_eckd_mod dasd_mod
          qeth qdio lcs ctcm ccwgroup fsm dm_mirror dm_region_hash dm_log
          dm_mod
        CPU: 0 PID: 9783 Comm: copy.sh Kdump: loaded Not tainted 5.1.0-rc 5 #1
      
      This patch simply removes the check entirely instead of trying to be
      clever about pages freed from interrupt context.  If a serious
      programming error was introduced, it is highly likely to be caught by
      prep_new_page() instead.
      
      Link: http://lkml.kernel.org/r/20190419085133.GH18914@techsingularity.net
      Fixes: 5e1f0f09 ("mm, compaction: capture a page under direct compaction")
      Signed-off-by: default avatarMel Gorman <mgorman@techsingularity.net>
      Reported-by: default avatarLi Wang <liwang@redhat.com>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ee8ab0ee
    • Mel Gorman's avatar
      mm: do not boost watermarks to avoid fragmentation for the DISCONTIG memory model · 24512228
      Mel Gorman authored
      Mikulas Patocka reported that commit 1c30844d ("mm: reclaim small
      amounts of memory when an external fragmentation event occurs") "broke"
      memory management on parisc.
      
      The machine is not NUMA but the DISCONTIG model creates three pgdats
      even though it's a UMA machine for the following ranges
      
              0) Start 0x0000000000000000 End 0x000000003fffffff Size   1024 MB
              1) Start 0x0000000100000000 End 0x00000001bfdfffff Size   3070 MB
              2) Start 0x0000004040000000 End 0x00000040ffffffff Size   3072 MB
      
      Mikulas reported:
      
      	With the patch 1c30844d, the kernel will incorrectly reclaim the
      	first zone when it fills up, ignoring the fact that there are two
      	completely free zones. Basiscally, it limits cache size to 1GiB.
      
      	For example, if I run:
      	# dd if=/dev/sda of=/dev/null bs=1M count=2048
      
      	- with the proper kernel, there should be "Buffers - 2GiB"
      	when this command finishes. With the patch 1c30844d, buffers
      	will consume just 1GiB or slightly more, because the kernel was
      	incorrectly reclaiming them.
      
      The page allocator and reclaim makes assumptions that pgdats really
      represent NUMA nodes and zones represent ranges and makes decisions on
      that basis.  Watermark boosting for small pgdats leads to unexpected
      results even though this would have behaved reasonably on SPARSEMEM.
      
      DISCONTIG is essentially deprecated and even parisc plans to move to
      SPARSEMEM so there is no need to be fancy, this patch simply disables
      watermark boosting by default on DISCONTIGMEM.
      
      Link: http://lkml.kernel.org/r/20190419094335.GJ18914@techsingularity.net
      Fixes: 1c30844d ("mm: reclaim small amounts of memory when an external fragmentation event occurs")
      Signed-off-by: default avatarMel Gorman <mgorman@techsingularity.net>
      Reported-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Tested-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
      Cc: Matthew Wilcox <willy@infradead.org>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      24512228