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Filename Latest commit message Latest commit date
Gerald Schaefer 4db28111b2 s390/gmap: improve THP splitting
commit ba925fa35057a062ac98c3e8138b013ce4ce351c upstream.

During s390_enable_sie(), we need to take care of splitting all qemu user
process THP mappings. This is currently done with follow_page(FOLL_SPLIT),
by simply iterating over all vma ranges, with PAGE_SIZE increment.

This logic is sub-optimal and can result in a lot of unnecessary overhead,
especially when using qemu and ASAN with large shadow map. Ilya reported
significant system slow-down with one CPU busy for a long time and overall
unresponsiveness.

Fix this by using walk_page_vma() and directly calling split_huge_pmd()
only for present pmds, which greatly reduces overhead.

Cc: <stable@vger.kernel.org> # v5.4+
Reported-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-08-19 08:16:29 +02:00
arch s390/gmap: improve THP splitting 2020-08-19 08:16:29 +02:00
block iocost: Fix check condition of iocg abs_vdebt 2020-08-19 08:15:58 +02:00
certs
crypto keys: asymmetric: fix error return code in software_key_query() 2020-07-22 09:33:04 +02:00
Documentation iio: improve IIO_CONCENTRATION channel type description 2020-08-19 08:16:07 +02:00
drivers s390/dasd: fix inability to use DASD with DIAG driver 2020-08-19 08:16:29 +02:00
fs fs/minix: reject too-large maximum file size 2020-08-19 08:16:28 +02:00
include bitfield.h: don't compile-time validate _val in FIELD_FIT 2020-08-19 08:16:28 +02:00
init x86: Fix early boot crash on gcc-10, third try 2020-05-20 08:20:34 +02:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel seccomp: Fix ioctl number for SECCOMP_IOCTL_NOTIF_ID_VALID 2020-08-19 08:15:58 +02:00
lib kobject: Avoid premature parent object freeing in kobject_cleanup() 2020-08-19 08:16:11 +02:00
LICENSES
mm mm/mmap.c: Add cond_resched() for exit_mmap() CPU stalls 2020-08-19 08:16:02 +02:00
net net: initialize fastreuse on inet_inherit_port 2020-08-19 08:16:23 +02:00
samples bpf: Fix fds_example SIGSEGV error 2020-08-19 08:16:03 +02:00
scripts recordmcount: only record relocation of type R_AARCH64_CALL26 on arm64. 2020-08-19 08:15:57 +02:00
security Smack: prevent underflow in smk_set_cipso() 2020-08-19 08:16:16 +02:00
sound ALSA: usb-audio: add quirk for Pioneer DDJ-RB 2020-08-19 08:16:27 +02:00
tools tools, bpftool: Fix wrong return value in do_dump() 2020-08-19 08:16:19 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: arm64: Don't inherit exec permission across page-table levels 2020-08-05 09:59:51 +02:00
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Makefile Linux 5.4.58 2020-08-11 15:33:42 +02:00
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.