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Aneesh Kumar K.V 16f6b67cf0 powerpc/book3s64/hash: Add cond_resched to avoid soft lockup warning
With large memory (8TB and more) hotplug, we can get soft lockup
warnings as below. These were caused by a long loop without any
explicit cond_resched which is a problem for !PREEMPT kernels.

Avoid this using cond_resched() while inserting hash page table
entries. We already do similar cond_resched() in __add_pages(), see
commit f64ac5e6e3 ("mm, memory_hotplug: add scheduling point to
__add_pages").

  rcu:     3-....: (24002 ticks this GP) idle=13e/1/0x4000000000000002 softirq=722/722 fqs=12001
   (t=24003 jiffies g=4285 q=2002)
  NMI backtrace for cpu 3
  CPU: 3 PID: 3870 Comm: ndctl Not tainted 5.3.0-197.18-default+ #2
  Call Trace:
    dump_stack+0xb0/0xf4 (unreliable)
    nmi_cpu_backtrace+0x124/0x130
    nmi_trigger_cpumask_backtrace+0x1ac/0x1f0
    arch_trigger_cpumask_backtrace+0x28/0x3c
    rcu_dump_cpu_stacks+0xf8/0x154
    rcu_sched_clock_irq+0x878/0xb40
    update_process_times+0x48/0x90
    tick_sched_handle.isra.16+0x4c/0x80
    tick_sched_timer+0x68/0xe0
    __hrtimer_run_queues+0x180/0x430
    hrtimer_interrupt+0x110/0x300
    timer_interrupt+0x108/0x2f0
    decrementer_common+0x114/0x120
  --- interrupt: 901 at arch_add_memory+0xc0/0x130
      LR = arch_add_memory+0x74/0x130
    memremap_pages+0x494/0x650
    devm_memremap_pages+0x3c/0xa0
    pmem_attach_disk+0x188/0x750
    nvdimm_bus_probe+0xac/0x2c0
    really_probe+0x148/0x570
    driver_probe_device+0x19c/0x1d0
    device_driver_attach+0xcc/0x100
    bind_store+0x134/0x1c0
    drv_attr_store+0x44/0x60
    sysfs_kf_write+0x64/0x90
    kernfs_fop_write+0x1a0/0x270
    __vfs_write+0x3c/0x70
    vfs_write+0xd0/0x260
    ksys_write+0xdc/0x130
    system_call+0x5c/0x68

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191001084656.31277-1-aneesh.kumar@linux.ibm.com
2019-11-05 22:24:57 +11:00
arch powerpc/book3s64/hash: Add cond_resched to avoid soft lockup warning 2019-11-05 22:24:57 +11:00
block block: sed-opal: fix sparse warning: convert __be64 data 2019-10-03 14:21:32 -06:00
certs PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
crypto Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
Documentation Kbuild fixes for v5.4 2019-10-05 12:56:59 -07:00
drivers ARM: SoC fixes 2019-10-05 17:18:43 -07:00
fs elf: don't use MAP_FIXED_NOREPLACE for elf executable mappings 2019-10-06 13:53:27 -07:00
include powerpc/mm/book3s64/radix: Flush the full mm even when need_flush_all is set 2019-11-05 22:24:18 +11:00
init Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
ipc ipc/sem.c: convert to use built-in RCU list checking 2019-09-25 17:51:41 -07:00
kernel dma-mapping regression fix for 5.4-rc2 2019-10-06 11:10:15 -07:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-10-05 08:50:15 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Merge branch 'hugepage-fallbacks' (hugepatch patches from David Rientjes) 2019-09-28 14:26:47 -07:00
net nfc: fix memory leak in llcp_sock_bind() 2019-10-04 18:31:36 -07:00
samples rpmsg updates for v5.4 2019-09-22 10:58:15 -07:00
scripts scripts/setlocalversion: clear local variable to make it work for sh 2019-10-05 15:29:49 +09:00
security powerpc/xmon: Restrict when kernel is locked down 2019-10-28 21:54:15 +11:00
sound sound fixes for 5.4-rc1 2019-09-24 16:46:16 -07:00
tools selftests/powerpc: Skip tm-signal-sigreturn-nt if TM not available 2019-11-05 11:26:20 +11:00
usr kbuild: update compile-test header list for v5.4-rc2 2019-10-05 15:29:49 +09:00
virt KVM/arm fixes for 5.4, take #1 2019-10-03 12:08:50 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2019-09-18 12:34:53 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS CREDITS: Update email address 2019-09-13 17:21:38 +03:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS kgdb patches for 5.4-rc2 2019-10-03 11:17:57 -07:00
Makefile Linux 5.4-rc2 2019-10-06 14:27:30 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.