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Filename Latest commit message Latest commit date
Naoya Horiguchi faf53def3b mm: hugetlb: soft-offline: dissolve_free_huge_page() return zero on !PageHuge
madvise(MADV_SOFT_OFFLINE) often returns -EBUSY when calling soft offline
for hugepages with overcommitting enabled.  That was caused by the
suboptimal code in current soft-offline code.  See the following part:

    ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL,
                            MIGRATE_SYNC, MR_MEMORY_FAILURE);
    if (ret) {
            ...
    } else {
            /*
             * We set PG_hwpoison only when the migration source hugepage
             * was successfully dissolved, because otherwise hwpoisoned
             * hugepage remains on free hugepage list, then userspace will
             * find it as SIGBUS by allocation failure. That's not expected
             * in soft-offlining.
             */
            ret = dissolve_free_huge_page(page);
            if (!ret) {
                    if (set_hwpoison_free_buddy_page(page))
                            num_poisoned_pages_inc();
            }
    }
    return ret;

Here dissolve_free_huge_page() returns -EBUSY if the migration source page
was freed into buddy in migrate_pages(), but even in that case we actually
has a chance that set_hwpoison_free_buddy_page() succeeds.  So that means
current code gives up offlining too early now.

dissolve_free_huge_page() checks that a given hugepage is suitable for
dissolving, where we should return success for !PageHuge() case because
the given hugepage is considered as already dissolved.

This change also affects other callers of dissolve_free_huge_page(), which
are cleaned up together.

[n-horiguchi@ah.jp.nec.com: v3]
  Link: http://lkml.kernel.org/r/1560761476-4651-3-git-send-email-n-horiguchi@ah.jp.nec.comLink: http://lkml.kernel.org/r/1560154686-18497-3-git-send-email-n-horiguchi@ah.jp.nec.com
Fixes: 6bc9b56433 ("mm: fix race on soft-offlining")
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: Chen, Jerry T <jerry.t.chen@intel.com>
Tested-by: Chen, Jerry T <jerry.t.chen@intel.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Xishi Qiu <xishi.qiuxishi@alibaba-inc.com>
Cc: "Chen, Jerry T" <jerry.t.chen@intel.com>
Cc: "Zhuo, Qiuxu" <qiuxu.zhuo@intel.com>
Cc: <stable@vger.kernel.org>	[4.19+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-06-29 16:43:45 +08:00
arch ARM: SoC fixes 2019-06-28 08:37:04 +08:00
block
certs
crypto
Documentation Char/Misc driver fixes for 5.2-rc6 2019-06-21 10:18:16 -07:00
drivers A handful of clk driver fixes and one core framework fix 2019-06-28 08:50:09 +08:00
fs signal: remove the wrong signal_pending() check in restore_user_sigmask() 2019-06-29 16:43:45 +08:00
include signal: remove the wrong signal_pending() check in restore_user_sigmask() 2019-06-29 16:43:45 +08:00
init
ipc
kernel signal: remove the wrong signal_pending() check in restore_user_sigmask() 2019-06-29 16:43:45 +08:00
lib SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
LICENSES
mm mm: hugetlb: soft-offline: dissolve_free_huge_page() return zero on !PageHuge 2019-06-29 16:43:45 +08:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-28 08:24:37 +08:00
samples samples: make pidfd-metadata fail gracefully on older kernels 2019-06-24 15:55:50 +02:00
scripts
security SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
sound
tools powerpc fixes for 5.2 #6 2019-06-24 21:20:39 +08:00
usr
virt SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS ARM: SoC fixes 2019-06-28 08:37:04 +08:00
Makefile Linux 5.2-rc6 2019-06-22 16:01:36 -07:00
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.