1. 02 Aug, 2016 2 commits
    • Jason Wang's avatar
      vhost: new device IOTLB API · 6b1e6cc7
      Jason Wang authored
      
      
      This patch tries to implement an device IOTLB for vhost. This could be
      used with userspace(qemu) implementation of DMA remapping
      to emulate an IOMMU for the guest.
      
      The idea is simple, cache the translation in a software device IOTLB
      (which is implemented as an interval tree) in vhost and use vhost_net
      file descriptor for reporting IOTLB miss and IOTLB
      update/invalidation. When vhost meets an IOTLB miss, the fault
      address, size and access can be read from the file. After userspace
      finishes the translation, it writes the translated address to the
      vhost_net file to update the device IOTLB.
      
      When device IOTLB is enabled by setting VIRTIO_F_IOMMU_PLATFORM all vq
      addresses set by ioctl are treated as iova instead of virtual address and
      the accessing can only be done through IOTLB instead of direct userspace
      memory access. Before each round or vq processing, all vq metadata is
      prefetched in device IOTLB to make sure no translation fault happens
      during vq processing.
      
      In most cases, virtqueues are contiguous even in virtual address space.
      The IOTLB translation for virtqueue itself may make it a little
      slower. We might add fast path cache on top of this patch.
      Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
      [mst: use virtio feature bit: VHOST_F_DEVICE_IOTLB -> VIRTIO_F_IOMMU_PLATFORM ]
      [mst: fix build warnings ]
      Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
      [ weiyj.lk: missing unlock on error ]
      Signed-off-by: default avatarWei Yongjun <weiyj.lk@gmail.com>
      6b1e6cc7
    • Michael S. Tsirkin's avatar
      vhost: drop vringh dependency · b2fbd8b0
      Michael S. Tsirkin authored
      
      
      vringh isn't used by vhost net or scsi - it's used
      by CAIF only at the moment. Drop the dependency.
      Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
      b2fbd8b0
  2. 01 Aug, 2016 14 commits
  3. 24 Jul, 2016 2 commits
  4. 23 Jul, 2016 22 commits
    • Linus Torvalds's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net · 107df032
      Linus Torvalds authored
      Pull networking fixes from David Miller:
      
       1) Fix memory leak in nftables, from Liping Zhang.
      
       2) Need to check result of vlan_insert_tag() in batman-adv otherwise we
          risk NULL skb derefs, from Sven Eckelmann.
      
       3) Check for dev_alloc_skb() failures in cfg80211, from Gregory
          Greenman.
      
       4) Handle properly when we have ppp_unregister_channel() happening in
          parallel with ppp_connect_channel(), from WANG Cong.
      
       5) Fix DCCP deadlock, from Eric Dumazet.
      
       6) Bail out properly in UDP if sk_filter() truncates the packet to be
          smaller than even the space that the protocol headers need.  From
          Michal Kubecek.
      
       7) Similarly for rose, dccp, and sctp, from Willem de Bruijn.
      
       8) Make TCP challenge ACKs less predictable, from Eric Dumazet.
      
       9) Fix infinite loop in bgmac_dma_tx_add() from Florian Fainelli.
      
      * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (65 commits)
        packet: propagate sock_cmsg_send() error
        net/mlx5e: Fix del vxlan port command buffer memset
        packet: fix second argument of sock_tx_timestamp()
        net: switchdev: change ageing_time type to clock_t
        Update maintainer for EHEA driver.
        net/mlx4_en: Add resilience in low memory systems
        net/mlx4_en: Move filters cleanup to a proper location
        sctp: load transport header after sk_filter
        net/sched/sch_htb: clamp xstats tokens to fit into 32-bit int
        net: cavium: liquidio: Avoid dma_unmap_single on uninitialized ndata
        net: nb8800: Fix SKB leak in nb8800_receive()
        et131x: Fix logical vs bitwise check in et131x_tx_timeout()
        vlan: use a valid default mtu value for vlan over macsec
        net: bgmac: Fix infinite loop in bgmac_dma_tx_add()
        mlxsw: spectrum: Prevent invalid ingress buffer mapping
        mlxsw: spectrum: Prevent overwrite of DCB capability fields
        mlxsw: spectrum: Don't emit errors when PFC is disabled
        mlxsw: spectrum: Indicate support for autonegotiation
        mlxsw: spectrum: Force link training according to admin state
        r8152: add MODULE_VERSION
        ...
      107df032
    • Linus Torvalds's avatar
      Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs · 88083e98
      Linus Torvalds authored
      Pull overlayfs fixes from Miklos Szeredi:
       "This contains a fix for a potential crash/corruption issue and another
        where the suid/sgid bits weren't cleared on write"
      
      * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
        ovl: verify upper dentry in ovl_remove_and_whiteout()
        ovl: Copy up underlying inode's ->i_mode to overlay inode
        ovl: handle ATTR_KILL*
      88083e98
    • Linus Torvalds's avatar
      Merge branch 'akpm' (patches from Andrew) · b1386ced
      Linus Torvalds authored
      Merge misc fixes from Andrew Morton:
       "Five fixes"
      
      * emailed patches from Andrew Morton <akpm@linux-foundation.org>:
        pps: do not crash when failed to register
        tools/vm/slabinfo: fix an unintentional printf
        testing/radix-tree: fix a macro expansion bug
        radix-tree: fix radix_tree_iter_retry() for tagged iterators.
        mm: memcontrol: fix cgroup creation failure after many small jobs
      b1386ced
    • Linus Torvalds's avatar
      Merge tag 'drm-fixes-for-v4.7-rc8-intel-kbl' of git://people.freedesktop.org/~airlied/linux · d15ae814
      Linus Torvalds authored
      Pull intel kabylake drm fixes from Dave Airlie:
       "As mentioned Intel has gathered all the Kabylake fixes from -next,
        which we've enabled in 4.7 for the first time, these are pretty much
        limited in scope to only affects kabylake, which is hw that isn't
        shipping yet.  So I'm mostly okay with it going in now.
      
        If we don't land this, it might be a good idea to disable kabylake
        support in 4.7 before we ship"
      
      * tag 'drm-fixes-for-v4.7-rc8-intel-kbl' of git://people.freedesktop.org/~airlied/linux: (28 commits)
        drm/i915/kbl: Introduce the first official DMC for Kabylake.
        drm/i915: Introduce Kabypoint PCH for Kabylake H/DT.
        drm/i915/gen9: implement WaConextSwitchWithConcurrentTLBInvalidate
        drm/i915/gen9: Add WaFbcHighMemBwCorruptionAvoidance
        drm/i195/fbc: Add WaFbcNukeOnHostModify
        drm/i915/gen9: Add WaFbcWakeMemOn
        drm/i915/gen9: Add WaFbcTurnOffFbcWatermark
        drm/i915/kbl: Add WaClearSlmSpaceAtContextSwitch
        drm/i915/gen9: Add WaEnableChickenDCPR
        drm/i915/kbl: Add WaDisableSbeCacheDispatchPortSharing
        drm/i915/kbl: Add WaDisableGafsUnitClkGating
        drm/i915/kbl: Add WaForGAMHang
        drm/i915: Add WaInsertDummyPushConstP for bxt and kbl
        drm/i915/kbl: Add WaDisableDynamicCreditSharing
        drm/i915/kbl: Add WaDisableGamClockGating
        drm/i915/gen9: Enable must set chicken bits in config0 reg
        drm/i915/kbl: Add WaDisableLSQCROPERFforOCL
        drm/i915/kbl: Add WaDisableSDEUnitClockGating
        drm/i915/kbl: Add WaDisableFenceDestinationToSLM for A0
        drm/i915/kbl: Add WaEnableGapsTsvCreditFix
        ...
      d15ae814
    • Linus Torvalds's avatar
      Merge tag 'drm-fixes-for-v4.7-rc8-intel' of git://people.freedesktop.org/~airlied/linux · 3f2625d7
      Linus Torvalds authored
      Pull drm fixes from Dave Airlie:
       "Two i915 regression fixes.
      
        Intel have submitted some Kabylake fixes I'll send separately, since
        this is the first kernel with kabylake support and they don't go much
        outside that area I think they should be fine"
      
      * tag 'drm-fixes-for-v4.7-rc8-intel' of git://people.freedesktop.org/~airlied/linux:
        drm/i915: add missing condition for committing planes on crtc
        drm/i915: Treat eDP as always connected, again
      3f2625d7
    • Linus Torvalds's avatar
      Merge tag 'm68k-for-v4.8-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k · 23218843
      Linus Torvalds authored
      Pull m68k upddates from Geert Uytterhoeven:
       - assorted spelling fixes
       - defconfig updates
      
      * tag 'm68k-for-v4.8-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k:
        m68k/defconfig: Update defconfigs for v4.7-rc2
        m68k: Assorted spelling fixes
      23218843
    • Linus Torvalds's avatar
      Merge tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc · 7825e0c4
      Linus Torvalds authored
      Pull ARM SoC fixes from Olof Johansson:
       "A handful of fixes before final release:
      
        Marvell Armada:
         - One to fix a typo in the devicetree specifying memory ranges for
           the crypto engine
         - Two to deal with marking PCI and device-memory as strongly ordered
           to avoid hardware deadlocks, in particular when enabling above
           crypto driver.
         - Compile fix for PM
      
        Allwinner:
         - DT clock fixes to deal with u-boot-enabled framebuffer (simplefb).
         - Make R8 (C.H.I.P. SoC) inherit system compatibility from A13 to
           make clocks register proper.
      
        Tegra:
         - Fix SD card voltage setting on the Tegra3 Beaver dev board
      
        Misc:
         - Two maintainers updates for STM32 and STi platforms"
      
      * tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
        ARM: tegra: beaver: Allow SD card voltage to be changed
        MAINTAINERS: update STi maintainer list
        MAINTAINERS: update STM32 maintainers list
        ARM: mvebu: compile pm code conditionally
        ARM: dts: sun7i: Fix pll3x2 and pll7x2 not having a parent clock
        ARM: dts: sunxi: Add pll3 to simplefb nodes clocks lists
        ARM: dts: armada-38x: fix MBUS_ID for crypto SRAM on Armada 385 Linksys
        ARM: mvebu: map PCI I/O regions strongly ordered
        ARM: mvebu: fix HW I/O coherency related deadlocks
        ARM: sunxi/dt: make the CHIP inherit from allwinner,sun5i-a13
      7825e0c4
    • Linus Torvalds's avatar
      Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 · 48d4ca56
      Linus Torvalds authored
      Pull crypto fixes from Herbert Xu:
       "This fixes a sporadic build failure in the qat driver as well as a
        memory corruption bug in rsa-pkcs1pad"
      
      * 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
        crypto: rsa-pkcs1pad - fix rsa-pkcs1pad request struct
        crypto: qat - make qat_asym_algs.o depend on asn1 headers
      48d4ca56
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security · 897473fc
      Linus Torvalds authored
      Pull key handling fixes from James Morris:
       "Quoting David Howells:
      
        Here are three miscellaneous fixes:
      
        (1) Fix a panic in some debugging code in PKCS#7.  This can only
            happen by explicitly inserting a #define DEBUG into the code.
      
        (2) Fix the calculation of the digest length in the PE file parser.
            This causes a failure where there should be a success.
      
        (3) Fix the case where an X.509 cert can be added as an asymmetric key
            to a trusted keyring with no trust restriction if no AKID is
            supplied.
      
        Bugs (1) and (2) aren't particularly problematic, but (3) allows a
        security check to be bypassed.  Happily, this is a recent regression
        and never made it into a released kernel"
      
      * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
        KEYS: Fix for erroneous trust of incorrectly signed X.509 certs
        pefile: Fix the failure of calculation for digest
        PKCS#7: Fix panic when referring to the empty AKID when DEBUG defined
      897473fc
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input · 3aa536d9
      Linus Torvalds authored
      Pull input fixes from Dmitry Torokhov:
       "A few more fixes for the input subsystem:
      
         - restore naming for tsc2005 touchscreens as some userspace match on it
         - fix out of bound access in legacy keyboard driver
         - fixup in RMI4 driver
      
        Everything is tagged for stable as well"
      
      * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
        Input: tsc200x - report proper input_dev name
        tty/vt/keyboard: fix OOB access in do_compute_shiftstate()
        Input: synaptics-rmi4 - fix maximum size check for F12 control register 8
      3aa536d9
    • Linus Torvalds's avatar
      Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm · f1894d83
      Linus Torvalds authored
      Pull libnvdimm fix from Dan Williams:
       "This contains a regression fix for a problem that was introduced in
        v4.7-rc6.
      
        In 4.7-rc1 we introduced auto-probing for the ACPI DSM (device-
        specific-method) format that the platform firmware implements for
        nvdimm devices.  We initially fixed a regression in probing the QEMU
        DSM implementation by making acpi_check_dsm() tolerant of the way QEMU
        reports the "0 DSMs supported" condition.
      
        However, that broke HPE platforms since that tolerance caused the
        driver to mistakenly match the 1-zero-byte response those platforms
        give to "unknown" commands.  Instead, we simply make the driver
        tolerant of not finding any supported DSMs.  This has been tested to
        work with both QEMU and HPE platforms.
      
        This commit has appeared in a -next release with no reported issues"
      
      * 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
        nfit: make DIMM DSMs optional
      f1894d83
    • Linus Torvalds's avatar
      Merge tag 'gpio-v4.7-6' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio · ee62f09b
      Linus Torvalds authored
      Pull GPIO fix from Linus Walleij:
       "Compile problem fix for Tegra,
      
        Sorry to send this in the last minute but Ingo says this build failure
        is very prominent so I'm not going to wait for v4.7 before sending it.
      
        It is a case of COMPILE_TEST causing more problems than it solves and
        I'm already swearing about me shooting myself in the foot with that
        gun :("
      
      * tag 'gpio-v4.7-6' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
        gpio: tegra: don't auto-enable for COMPILE_TEST
      ee62f09b
    • Linus Torvalds's avatar
      Merge tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux · 62cd69d5
      Linus Torvalds authored
      Pull clk fixes from Michael Turquette:
       "Fix a bug in the at91 clk driver, two compile time warnings in sunxi
        clk drivers, and one bug in a sunxi clk driver introduced in the 4.7
        merge window"
      
      * tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
        clk: at91: fix clk_programmable_set_parent()
        clk: sunxi: remove unused variable
        clk: sunxi: display: Add per-clock flags
        clk: sunxi: tcon-ch1: Do not return a negative error in get_parent
      62cd69d5
    • Linus Torvalds's avatar
      Merge branch 'for-4.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata · a933f80d
      Linus Torvalds authored
      Pull libata fix from Tejun Heo:
       "Another fallout from max_sectors bump a couple years ago.  The lite-on
        optical drive times out on large requests"
      
      * 'for-4.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata:
        libata: LITE-ON CX1-JB256-HP needs lower max_sectors
      a933f80d
    • Linus Torvalds's avatar
      Merge tag 'mmc-v4.7-rc7' of git://git.linaro.org/people/ulf.hansson/mmc · ea4b3cfa
      Linus Torvalds authored
      Pull MMC fixes from Ulf Hansson:
       "Here are a few late mmc fixes intended for v4.7 final.
      
        MMC core:
         - Fix eMMC packed command header endianness
         - Fix free of uninitialized buffer for mmc ioctl
      
        MMC host:
         - pxamci: Fix potential oops in ->probe()"
      
      * tag 'mmc-v4.7-rc7' of git://git.linaro.org/people/ulf.hansson/mmc:
        mmc: pxamci: fix potential oops
        mmc: block: fix packed command header endianness
        mmc: block: fix free of uninitialized 'idata->buf'
      ea4b3cfa
    • Linus Torvalds's avatar
      Merge tag 'sound-4.7-fix2' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound · b6cbecae
      Linus Torvalds authored
      Pull sound fixes from Takashi Iwai:
       "No surprise, just a few small fixes: a couple of changes are seen in
        the core part, and both of them are rather for unusual error paths.
      
        The rest are the regular HD-audio fixes and one USB-audio regression
        fix"
      
      * tag 'sound-4.7-fix2' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
        ALSA: usb-audio: Fix quirks code is not called
        ALSA: hda: add AMD Stoney PCI ID with proper driver caps
        ALSA: hda - fix use-after-free after module unload
        ALSA: pcm: Free chmap at PCM free callback, too
        ALSA: ctl: Stop notification after disconnection
        ALSA: hda/realtek - add new pin definition in alc225 pin quirk table
      b6cbecae
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.dk/linux-block · ff8d6fac
      Linus Torvalds authored
      Pull NVMe fix from Jens Axboe:
       "Late addition here, it's basically a revert of a patch that was added
        in this merge window, but has proven to cause problems.
      
        This is swapping out the RCU based namespace protection with a good
        old mutex instead"
      
      * 'for-linus' of git://git.kernel.dk/linux-block:
        nvme: Remove RCU namespace protection
      ff8d6fac
    • Jiri Slaby's avatar
      pps: do not crash when failed to register · 368301f2
      Jiri Slaby authored
      With this command sequence:
      
        modprobe plip
        modprobe pps_parport
        rmmod pps_parport
      
      the partport_pps modules causes this crash:
      
        BUG: unable to handle kernel NULL pointer dereference at (null)
        IP: parport_detach+0x1d/0x60 [pps_parport]
        Oops: 0000 [#1] SMP
        ...
        Call Trace:
          parport_unregister_driver+0x65/0xc0 [parport]
          SyS_delete_module+0x187/0x210
      
      The sequence that builds up to this is:
      
       1) plip is loaded and takes the parport device for exclusive use:
      
          plip0: Parallel port at 0x378, using IRQ 7.
      
       2) pps_parport then fails to grab the device:
      
          pps_parport: parallel port PPS client
          parport0: cannot grant exclusive access for device pps_parport
          pps_parport: couldn't register with parport0
      
       3) rmmod of pps_parport is then killed because it tries to access
          pardev->name, but pardev (taken from port->cad) is NULL.
      
      So add a check for NULL in the test there too.
      
      Link: http://lkml.kernel.org/r/20160714115245.12651-1-jslaby@suse.cz
      
      Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
      Acked-by: default avatarRodolfo Giometti <giometti@enneenne.com>
      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>
      368301f2
    • Dan Carpenter's avatar
      tools/vm/slabinfo: fix an unintentional printf · 2d6a4d64
      Dan Carpenter authored
      The curly braces are missing here so we print stuff unintentionally.
      
      Fixes: 9da4714a ('slub: slabinfo update for cmpxchg handling')
      Link: http://lkml.kernel.org/r/20160715211243.GE19522@mwanda
      
      Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
      Acked-by: default avatarChristoph Lameter <cl@linux.com>
      Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
      Cc: Colin Ian King <colin.king@canonical.com>
      Cc: Laura Abbott <labbott@fedoraproject.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2d6a4d64
    • Dan Carpenter's avatar
      testing/radix-tree: fix a macro expansion bug · b301aac5
      Dan Carpenter authored
      There are no parentheses around this macro and it causes a problem when
      we do:
      
      	index = rand() % THRASH_SIZE;
      
      Link: http://lkml.kernel.org/r/20160715210953.GC19522@mwanda
      
      Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
      Acked-by: default avatarRoss Zwisler <ross.zwisler@linux.intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b301aac5
    • Andrey Ryabinin's avatar
      radix-tree: fix radix_tree_iter_retry() for tagged iterators. · 3cb9185c
      Andrey Ryabinin authored
      radix_tree_iter_retry() resets slot to NULL, but it doesn't reset tags.
      Then NULL slot and non-zero iter.tags passed to radix_tree_next_slot()
      leading to crash:
      
        RIP: radix_tree_next_slot include/linux/radix-tree.h:473
          find_get_pages_tag+0x334/0x930 mm/filemap.c:1452
        ....
        Call Trace:
          pagevec_lookup_tag+0x3a/0x80 mm/swap.c:960
          mpage_prepare_extent_to_map+0x321/0xa90 fs/ext4/inode.c:2516
          ext4_writepages+0x10be/0x2b20 fs/ext4/inode.c:2736
          do_writepages+0x97/0x100 mm/page-writeback.c:2364
          __filemap_fdatawrite_range+0x248/0x2e0 mm/filemap.c:300
          filemap_write_and_wait_range+0x121/0x1b0 mm/filemap.c:490
          ext4_sync_file+0x34d/0xdb0 fs/ext4/fsync.c:115
          vfs_fsync_range+0x10a/0x250 fs/sync.c:195
          vfs_fsync fs/sync.c:209
          do_fsync+0x42/0x70 fs/sync.c:219
          SYSC_fdatasync fs/sync.c:232
          SyS_fdatasync+0x19/0x20 fs/sync.c:230
          entry_SYSCALL_64_fastpath+0x23/0xc1 arch/x86/entry/entry_64.S:207
      
      We must reset iterator's tags to bail out from radix_tree_next_slot()
      and go to the slow-path in radix_tree_next_chunk().
      
      Fixes: 46437f9a ("radix-tree: fix race in gang lookup")
      Link: http://lkml.kernel.org/r/1468495196-10604-1-git-send-email-aryabinin@virtuozzo.com
      
      Signed-off-by: default avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
      Reported-by: default avatarDmitry Vyukov <dvyukov@google.com>
      Acked-by: default avatarKonstantin Khlebnikov <koct9i@gmail.com>
      Cc: Matthew Wilcox <willy@linux.intel.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
      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>
      3cb9185c
    • Johannes Weiner's avatar
      mm: memcontrol: fix cgroup creation failure after many small jobs · 73f576c0
      Johannes Weiner authored
      The memory controller has quite a bit of state that usually outlives the
      cgroup and pins its CSS until said state disappears.  At the same time
      it imposes a 16-bit limit on the CSS ID space to economically store IDs
      in the wild.  Consequently, when we use cgroups to contain frequent but
      small and short-lived jobs that leave behind some page cache, we quickly
      run into the 64k limitations of outstanding CSSs.  Creating a new cgroup
      fails with -ENOSPC while there are only a few, or even no user-visible
      cgroups in existence.
      
      Although pinning CSSs past cgroup removal is common, there are only two
      instances that actually need an ID after a cgroup is deleted: cache
      shadow entries and swapout records.
      
      Cache shadow entries reference the ID weakly and can deal with the CSS
      having disappeared when it's looked up later.  They pose no hurdle.
      
      Swap-out records do need to pin the css to hierarchically attribute
      swapins after the cgroup has been deleted; though the only pages that
      remain swapped out after offlining are tmpfs/shmem pages.  And those
      references are under the user's control, so they are manageable.
      
      This patch introduces a private 16-bit memcg ID and switches swap and
      cache shadow entries over to using that.  This ID can then be recycled
      after offlining when the CSS remains pinned only by objects that don't
      specifically need it.
      
      This script demonstrates the problem by faulting one cache page in a new
      cgroup and deleting it again:
      
        set -e
        mkdir -p pages
        for x in `seq 128000`; do
          [ $((x % 1000)) -eq 0 ] && echo $x
          mkdir /cgroup/foo
          echo $$ >/cgroup/foo/cgroup.procs
          echo trex >pages/$x
          echo $$ >/cgroup/cgroup.procs
          rmdir /cgroup/foo
        done
      
      When run on an unpatched kernel, we eventually run out of possible IDs
      even though there are no visible cgroups:
      
        [root@ham ~]# ./cssidstress.sh
        [...]
        65000
        mkdir: cannot create directory '/cgroup/foo': No space left on device
      
      After this patch, the IDs get released upon cgroup destruction and the
      cache and css objects get released once memory reclaim kicks in.
      
      [hannes@cmpxchg.org: init the IDR]
        Link: http://lkml.kernel.org/r/20160621154601.GA22431@cmpxchg.org
      Fixes: b2052564 ("mm: memcontrol: continue cache reclaim from offlined groups")
      Link: http://lkml.kernel.org/r/20160617162516.GD19084@cmpxchg.org
      
      Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Reported-by: default avatarJohn Garcia <john.garcia@mesosphere.io>
      Reviewed-by: default avatarVladimir Davydov <vdavydov@virtuozzo.com>
      Acked-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Nikolay Borisov <kernel@kyup.com>
      Cc: <stable@vger.kernel.org>	[3.19+]
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      73f576c0