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Qian Cai a9ee3a63db debugobjects: call debug_objects_mem_init eariler
The current value of the early boot static pool size, 1024 is not big
enough for systems with large number of CPUs with timer or/and workqueue
objects selected.  As the results, systems have 60+ CPUs with both timer
and workqueue objects enabled could trigger "ODEBUG: Out of memory.
ODEBUG disabled".

Some debug objects are allocated during the early boot.  Enabling some
options like timers or workqueue objects may increase the size required
significantly with large number of CPUs.  For example,

CONFIG_DEBUG_OBJECTS_TIMERS:
No. CPUs x 2 (worker pool) objects:
start_kernel
  workqueue_init_early
    init_worker_pool
      init_timer_key
        debug_object_init

plus No. CPUs objects (CONFIG_HIGH_RES_TIMERS):
sched_init
  hrtick_rq_init
    hrtimer_init

CONFIG_DEBUG_OBJECTS_WORK:
No. CPUs objects:
vmalloc_init
  __init_work

plus No. CPUs x 6 (workqueue) objects:
workqueue_init_early
  alloc_workqueue
    __alloc_workqueue_key
      alloc_and_link_pwqs
        init_pwq

Also, plus No. CPUs objects:
perf_event_init
  __init_srcu_struct
    init_srcu_struct_fields
      init_srcu_struct_nodes
        __init_work

However, none of the things are actually used or required before
debug_objects_mem_init() is invoked, so just move the call right before
vmalloc_init().

According to tglx, "the reason why the call is at this place in
start_kernel() is historical.  It's because back in the days when
debugobjects were added the memory allocator was enabled way later than
today."

Link: http://lkml.kernel.org/r/20181126102407.1836-1-cai@gmx.us
Signed-off-by: Qian Cai <cai@gmx.us>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <longman@redhat.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:45 -08:00
Documentation kasan: update documentation 2018-12-28 12:11:44 -08:00
LICENSES This is a fairly typical cycle for documentation. There's some welcome 2018-10-24 18:01:11 +01:00
arch sh: lib: convert to SPDX identifiers 2018-12-28 12:11:45 -08:00
block block: Fix null_blk_zoned creation failure with small number of zones 2018-12-11 16:19:38 -07:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-12-27 13:53:32 -08:00
drivers Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-12-27 13:53:32 -08:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs File locking changes for v4.21 2018-12-27 17:12:30 -08:00
include kasan: add __must_check annotations to kasan hooks 2018-12-28 12:11:44 -08:00
init debugobjects: call debug_objects_mem_init eariler 2018-12-28 12:11:45 -08:00
ipc ipc: IPCMNI limit check for semmni 2018-10-31 08:54:14 -07:00
kernel Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-12-27 13:53:32 -08:00
lib debugobjects: call debug_objects_mem_init eariler 2018-12-28 12:11:45 -08:00
mm kasan: add SPDX-License-Identifier mark to source files 2018-12-28 12:11:44 -08:00
net Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-12-27 13:53:32 -08:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-12-27 13:04:52 -08:00
scripts scripts/tags.sh: add more declarations 2018-12-28 12:11:44 -08:00
security Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-12-27 13:53:32 -08:00
sound xen: features and fixes for 4.21 2018-12-26 11:35:07 -08:00
tools Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-12-27 13:53:32 -08:00
usr initramfs: move gen_initramfs_list.sh from scripts/ to usr/ 2018-08-22 23:21:44 +09:00
virt Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-12-26 13:07:19 -08:00
.clang-format page cache: Convert find_get_pages_contig to XArray 2018-10-21 10:46:34 -04:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap Merge tag 'nand/for-4.21' of git://git.infradead.org/linux-mtd into mtd/next 2018-12-18 19:59:16 +01:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: update entry for MMP platform 2018-12-03 12:39:57 -08:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-12-27 13:53:32 -08:00
Makefile Linux 4.20 2018-12-23 15:55:59 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

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.