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David Matlack 89d9a43c1d KVM: selftests: Wait for all vCPU to be created before entering guest mode
Thread creation requires taking the mmap_sem in write mode, which causes
vCPU threads running in guest mode to block while they are populating
memory. Fix this by waiting for all vCPU threads to be created and start
running before entering guest mode on any one vCPU thread.

This substantially improves the "Populate memory time" when using 1GiB
pages since it allows all vCPUs to zero pages in parallel rather than
blocking because a writer is waiting (which is waiting for another vCPU
that is busy zeroing a 1GiB page).

Before:

  $ ./dirty_log_perf_test -v256 -s anonymous_hugetlb_1gb
  ...
  Populate memory time: 52.811184013s

After:

  $ ./dirty_log_perf_test -v256 -s anonymous_hugetlb_1gb
  ...
  Populate memory time: 10.204573342s

Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20211111001257.1446428-4-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-11-16 07:43:28 -05:00
arch KVM: x86: Drop arbitrary KVM_SOFT_MAX_VCPUS 2021-11-11 10:56:24 -05:00
block block-5.15-2021-10-01 2021-10-02 11:00:36 -07:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2021-08-30 12:57:10 -07:00
Documentation KVM/arm64 updates for Linux 5.16 2021-10-31 02:28:48 -04:00
drivers KVM/arm64 updates for Linux 5.16 2021-10-31 02:28:48 -04:00
fs elf: don't use MAP_FIXED_NOREPLACE for elf interpreter mappings 2021-10-03 14:02:58 -07:00
include KVM/arm64 updates for Linux 5.16 2021-10-31 02:28:48 -04:00
init Merge branch 'work.init' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2021-09-24 10:18:07 -07:00
ipc ipc: remove memcg accounting for sops objects in do_semtimedop() 2021-09-14 10:22:11 -07:00
kernel - Tell the compiler to always inline is_percpu_thread() 2021-10-03 10:49:00 -07:00
lib lib/zlib_inflate/inffast: check config in C to avoid unused function warning 2021-09-24 16:13:35 -07:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm mm: fix uninitialized use in overcommit_policy_handler 2021-09-24 16:13:35 -07:00
net af_unix: fix races in sk_peer_pid and sk_peer_cred accesses 2021-09-30 14:18:40 +01:00
samples kgdb patches for 5.15 2021-09-07 12:08:04 -07:00
scripts kasan: always respect CONFIG_KASAN_STACK 2021-09-24 16:13:35 -07:00
security selinux,smack: fix subjective/objective credential use mixups 2021-09-23 12:30:59 -04:00
sound ALSA: pcsp: Make hrtimer forwarding more robust 2021-09-28 10:58:08 +02:00
tools KVM: selftests: Wait for all vCPU to be created before entering guest mode 2021-11-16 07:43:28 -05:00
usr .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
virt kvm: irqfd: avoid update unmodified entries of the routing 2021-09-30 04:27:10 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: update email address of Matthias Fuchs and Thomas Körper 2021-08-19 09:39:44 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: move Murali Karicheri to credits 2021-04-29 15:47:30 -07:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS KVM/arm64 updates for Linux 5.16 2021-10-31 02:28:48 -04:00
Makefile Linux 5.15-rc4 2021-10-03 14:08:47 -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.