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A mirror of the official Linux kernel repository just in case
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Mike Kravetz 22146c3ce9 hugetlbfs: dirty pages as they are added to pagecache 
Some test systems were experiencing negative huge page reserve counts and
incorrect file block counts.  This was traced to /proc/sys/vm/drop_caches
removing clean pages from hugetlbfs file pagecaches.  When non-hugetlbfs
explicit code removes the pages, the appropriate accounting is not
performed.

This can be recreated as follows:
 fallocate -l 2M /dev/hugepages/foo
 echo 1 > /proc/sys/vm/drop_caches
 fallocate -l 2M /dev/hugepages/foo
 grep -i huge /proc/meminfo
   AnonHugePages:         0 kB
   ShmemHugePages:        0 kB
   HugePages_Total:    2048
   HugePages_Free:     2047
   HugePages_Rsvd:    18446744073709551615
   HugePages_Surp:        0
   Hugepagesize:       2048 kB
   Hugetlb:         4194304 kB
 ls -lsh /dev/hugepages/foo
   4.0M -rw-r--r--. 1 root root 2.0M Oct 17 20:05 /dev/hugepages/foo

To address this issue, dirty pages as they are added to pagecache.  This
can easily be reproduced with fallocate as shown above.  Read faulted
pages will eventually end up being marked dirty.  But there is a window
where they are clean and could be impacted by code such as drop_caches.
So, just dirty them all as they are added to the pagecache.

Link: http://lkml.kernel.org/r/b5be45b8-5afe-56cd-9482-28384699a049@oracle.com
Fixes: 6bda666a03 ("hugepages: fold find_or_alloc_pages into huge_no_page()")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Mihcla Hocko <mhocko@suse.com>
Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26 16:38:16 -07:00
arch Revert "x86/e820: put !E820_TYPE_RAM regions into memblock.reserved" 2018-10-26 16:38:15 -07:00
block sched: loadavg: consolidate LOAD_INT, LOAD_FRAC, CALC_LOAD 2018-10-26 16:26:32 -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 2018-10-25 16:43:35 -07:00
Documentation mm: don't raise MEMCG_OOM event due to failed high-order allocation 2018-10-26 16:38:14 -07:00
drivers sched: loadavg: consolidate LOAD_INT, LOAD_FRAC, CALC_LOAD 2018-10-26 16:26:32 -07:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs mm: zero-seek shrinkers 2018-10-26 16:26:33 -07:00
include mm: split SWP_FILE into SWP_ACTIVATED and SWP_FS 2018-10-26 16:38:15 -07:00
init psi: cgroup support 2018-10-26 16:26:32 -07:00
ipc Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-10-25 11:14:36 -07:00
kernel mm: defer ZONE_DEVICE page initialization to the point where we init pgmap 2018-10-26 16:26:34 -07:00
lib lib/test_kasan.c: add tests for several string/memory API functions 2018-10-26 16:25:18 -07:00
LICENSES This is a fairly typical cycle for documentation. There's some welcome 2018-10-24 18:01:11 +01:00
mm hugetlbfs: dirty pages as they are added to pagecache 2018-10-26 16:38:16 -07:00
net Merge branch 'for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2018-10-25 17:15:46 -07:00
samples Char/Misc driver patches for 4.20-rc1 2018-10-26 09:11:43 -07:00
scripts scripts/tags.sh: add DECLARE_HASHTABLE() 2018-10-26 16:25:18 -07:00
security Merge branch 'next-loadpin' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2018-10-25 13:32:00 -07:00
sound sound updates for 4.20 2018-10-25 09:00:15 -07:00
tools tools/testing/selftests/vm/map_fixed_noreplace.c: add test for MAP_FIXED_NOREPLACE 2018-10-26 16:38:15 -07:00
usr initramfs: move gen_initramfs_list.sh from scripts/ to usr/ 2018-08-22 23:21:44 +09:00
virt Revert "mm, mmu_notifier: annotate mmu notifiers with blockable invalidate callbacks" 2018-10-26 16:25:19 -07:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.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 libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
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 Char/Misc driver patches for 4.20-rc1 2018-10-26 09:11:43 -07:00
Makefile Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-10-23 13:08:53 +01:00
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.