Merge tag 'prlimit-tasklist_lock-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull tasklist_lock optimizations from Eric Biederman:
"prlimit and getpriority t

Merge tag 'prlimit-tasklist_lock-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull tasklist_lock optimizations from Eric Biederman:
"prlimit and getpriority tasklist_lock optimizations

The tasklist_lock popped up as a scalability bottleneck on some
testing workloads. The readlocks in do_prlimit and set/getpriority are
not necessary in all cases.

Based on a cycles profile, it looked like ~87% of the time was spent
in the kernel, ~42% of which was just trying to get *some* spinlock
(queued_spin_lock_slowpath, not necessarily the tasklist_lock).

The big offenders (with rough percentages in cycles of the overall
trace):
- do_wait 11%
- setpriority 8% (done previously in commit 7f8ca0edfe07)
- kill 8%
- do_exit 5%
- clone 3%
- prlimit64 2% (this patchset)
- getrlimit 1% (this patchset)

I can't easily test this patchset on the original workload for various
reasons. Instead, I used the microbenchmark below to at least verify
there was some improvement. This patchset had a 28% speedup (12% from
baseline to set/getprio, then another 14% for prlimit).

This series used to do the setpriority case, but an almost identical
change was merged as commit 7f8ca0edfe07 ("kernel/sys.c: only take
tasklist_lock for get/setpriority(PRIO_PGRP)") so that has been
dropped from here.

One interesting thing is that my libc's getrlimit() was calling
prlimit64, so hoisting the read_lock(tasklist_lock) into sys_prlimit64
had no effect - it essentially optimized the older syscalls only. I
didn't do that in this patchset, but figured I'd mention it since it
was an option from the previous patch's discussion"

micobenchmark.c:
---------------
int main(int argc, char **argv)
{
pid_t child;
struct rlimit rlim[1];

fork(); fork(); fork(); fork(); fork(); fork();

for (int i = 0; i < 5000; i++) {
child = fork();
if (child < 0)
exit(1);
if (child > 0) {
usleep(1000);
kill(child, SIGTERM);
waitpid(child, NULL, 0);
} else {
for (;;) {
setpriority(PRIO_PROCESS, 0,
getpriority(PRIO_PROCESS, 0));
getrlimit(RLIMIT_CPU, rlim);
}
}
}

return 0;
}

Link: https://lore.kernel.org/lkml/20211213220401.1039578-1-brho@google.com/ [v1]
Link: https://lore.kernel.org/lkml/20220105212828.197013-1-brho@google.com/ [v2]
Link: https://lore.kernel.org/lkml/20220106172041.522167-1-brho@google.com/ [v3]

* tag 'prlimit-tasklist_lock-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
prlimit: do not grab the tasklist_lock
prlimit: make do_prlimit() static

show more ...

Merge branch 'for-5.18/amd-sfh' into for-linus

- dead code elimination (Christophe JAILLET)

Merge branch 'edac-amd64' into edac-updates-for-v5.18

Signed-off-by: Borislav Petkov <bp@suse.de>

Merge tag 'spi-nor/for-5.18' into mtd/next

SPI NOR core changes:
- move vendor specific code out of the core into vendor drivers.
- unify all function and object names in the vendor modules.
- make

Merge tag 'spi-nor/for-5.18' into mtd/next

SPI NOR core changes:
- move vendor specific code out of the core into vendor drivers.
- unify all function and object names in the vendor modules.
- make setup() callback optional to improve readability.
- skip erase logic when the SPI_NOR_NO_ERASE flag is set at flash
declaration.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

show more ...

Merge drm/drm-fixes into drm-misc-fixes

Backmerging drm/drm-fixes for commit 3755d35ee1d2 ("drm/panel: Select
DRM_DP_HELPER for DRM_PANEL_EDP").

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.d

Merge drm/drm-fixes into drm-misc-fixes

Backmerging drm/drm-fixes for commit 3755d35ee1d2 ("drm/panel: Select
DRM_DP_HELPER for DRM_PANEL_EDP").

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

show more ...

Merge tag 'v5.17-rc8' into usb-next

We need the Xen USB fixes as other patches depend on those changes.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge tag 'v5.17-rc8' into sched/core, to pick up fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge tag 'v5.17-rc8' into next

Sync up with mainline to again get the latest changes in HID subsystem.

Merge remote-tracking branch 'torvalds/master' into perf/core

To pick up fixes that went thru perf/urgent.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Merge tag 'v5.17-rc8' into irq/core, to fix conflicts

Conflicts:
drivers/pinctrl/pinctrl-starfive.c

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge 5.17-rc8 into staging-next

We need the staging fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

net/dsa/dsa2.c
commit afb3cc1a397d ("net: dsa: unlock the rtnl_mutex when dsa_master_setup() fails")
commit e83d56537859 ("net: dsa

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

net/dsa/dsa2.c
commit afb3cc1a397d ("net: dsa: unlock the rtnl_mutex when dsa_master_setup() fails")
commit e83d56537859 ("net: dsa: replay master state events in dsa_tree_{setup,teardown}_master")
https://lore.kernel.org/all/20220307101436.7ae87da0@canb.auug.org.au/

drivers/net/ethernet/intel/ice/ice.h
commit 97b0129146b1 ("ice: Fix error with handling of bonding MTU")
commit 43113ff73453 ("ice: add TTY for GNSS module for E810T device")
https://lore.kernel.org/all/20220310112843.3233bcf1@canb.auug.org.au/

drivers/staging/gdm724x/gdm_lte.c
commit fc7f750dc9d1 ("staging: gdm724x: fix use after free in gdm_lte_rx()")
commit 4bcc4249b4cf ("staging: Use netif_rx().")
https://lore.kernel.org/all/20220308111043.1018a59d@canb.auug.org.au/

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

prlimit: do not grab the tasklist_lock

Unnecessarily grabbing the tasklist_lock can be a scalability bottleneck
for workloads that also must grab the tasklist_lock for waiting,
killing, and cloning.

prlimit: do not grab the tasklist_lock

Unnecessarily grabbing the tasklist_lock can be a scalability bottleneck
for workloads that also must grab the tasklist_lock for waiting,
killing, and cloning.

The tasklist_lock was grabbed to protect tsk->sighand from disappearing
(becoming NULL). tsk->signal was already protected by holding a
reference to tsk.

update_rlimit_cpu() assumed tsk->sighand != NULL. With this commit, it
attempts to lock_task_sighand(). However, this means that
update_rlimit_cpu() can fail. This only happens when a task is exiting.
Note that during exec, sighand may *change*, but it will not be NULL.

Prior to this commit, the do_prlimit() ensured that update_rlimit_cpu()
would not fail by read locking the tasklist_lock and checking tsk->sighand
!= NULL.

If update_rlimit_cpu() fails, there may be other tasks that are not
exiting that share tsk->signal. However, the group_leader is the last
task to be released, so if we cannot update_rlimit_cpu(group_leader),
then the entire process is exiting.

The only other caller of update_rlimit_cpu() is
selinux_bprm_committing_creds(). It has tsk == current, so
update_rlimit_cpu() cannot fail (current->sighand cannot disappear
until current exits).

This change resulted in a 14% speedup on a microbenchmark where parents
kill and wait on their children, and children getpriority, setpriority,
and getrlimit.

Signed-off-by: Barret Rhoden <brho@google.com>
Link: https://lkml.kernel.org/r/20220106172041.522167-4-brho@google.com
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

show more ...

prlimit: make do_prlimit() static

There are no other callers in the kernel.

Fixed up a comment format and whitespace issue when moving do_prlimit()
higher in sys.c.

Signed-off-by: Barret Rhoden <b

prlimit: make do_prlimit() static

There are no other callers in the kernel.

Fixed up a comment format and whitespace issue when moving do_prlimit()
higher in sys.c.

Signed-off-by: Barret Rhoden <brho@google.com>
Link: https://lkml.kernel.org/r/20220106172041.522167-3-brho@google.com
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

show more ...

Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
"8 patches.

Subsystems affected by this patch series: mm (hugetlb, pagemap, and
userfaultfd), memfd, selftests, a

Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
"8 patches.

Subsystems affected by this patch series: mm (hugetlb, pagemap, and
userfaultfd), memfd, selftests, and kconfig"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
configs/debug: set CONFIG_DEBUG_INFO=y properly
proc: fix documentation and description of pagemap
kselftest/vm: fix tests build with old libc
memfd: fix F_SEAL_WRITE after shmem huge page allocated
mm: fix use-after-free when anon vma name is used after vma is freed
mm: prevent vm_area_struct::anon_name refcount saturation
mm: refactor vm_area_struct::anon_vma_name usage code
selftests/vm: cleanup hugetlb file after mremap test

show more ...

mm: refactor vm_area_struct::anon_vma_name usage code

Avoid mixing strings and their anon_vma_name referenced pointers by
using struct anon_vma_name whenever possible. This simplifies the code
and

mm: refactor vm_area_struct::anon_vma_name usage code

Avoid mixing strings and their anon_vma_name referenced pointers by
using struct anon_vma_name whenever possible. This simplifies the code
and allows easier sharing of anon_vma_name structures when they
represent the same name.

[surenb@google.com: fix comment]

Link: https://lkml.kernel.org/r/20220223153613.835563-1-surenb@google.com
Link: https://lkml.kernel.org/r/20220224231834.1481408-1-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Colin Cross <ccross@google.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Alexey Gladkov <legion@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Chris Hyser <chris.hyser@oracle.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Xiaofeng Cao <caoxiaofeng@yulong.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

show more ...

Merge tag 'v5.17-rc4' into for-linus

Merge with mainline to get the Intel ASoC generic helpers header and
other changes.

Merge 5.17-rc6 into tty-next

We need the tty/serial fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge 5.17-rc6 into usb-next

We need the USB fixes in here, and it resolves a merge conflict in:
drivers/usb/dwc3/dwc3-pci.c

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge 5.17-rc6 into staging-next

We need the staging fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge 5.17-rc6 into driver-core-next

We need the driver core fix in here as well for future changes.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge 5.17-rc6 into char-misc-next

We need the char-misc fixes in here.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Backmerge tag 'v5.17-rc6' into drm-next

This backmerges v5.17-rc6 so I can merge some amdgpu and some tegra changes on top.

Signed-off-by: Dave Airlie <airlied@redhat.com>

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

tools/testing/selftests/net/mptcp/mptcp_join.sh
34aa6e3bccd8 ("selftests: mptcp: add ip mptcp wrappers")

857898eb4b28 ("selftests:

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

tools/testing/selftests/net/mptcp/mptcp_join.sh
34aa6e3bccd8 ("selftests: mptcp: add ip mptcp wrappers")

857898eb4b28 ("selftests: mptcp: add missing join check")
6ef84b1517e0 ("selftests: mptcp: more robust signal race test")
https://lore.kernel.org/all/20220221131842.468893-1-broonie@kernel.org/

drivers/net/ethernet/mellanox/mlx5/core/en/tc/act/act.h
drivers/net/ethernet/mellanox/mlx5/core/en/tc/act/ct.c
fb7e76ea3f3b6 ("net/mlx5e: TC, Skip redundant ct clear actions")
c63741b426e11 ("net/mlx5e: Fix MPLSoUDP encap to use MPLS action information")

09bf97923224f ("net/mlx5e: TC, Move pedit_headers_action to parse_attr")
84ba8062e383 ("net/mlx5e: Test CT and SAMPLE on flow attr")
efe6f961cd2e ("net/mlx5e: CT, Don't set flow flag CT for ct clear flow")
3b49a7edec1d ("net/mlx5e: TC, Reject rules with multiple CT actions")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

Merge tag 'irq-api-2022-02-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into i2c/for-mergewindow

Provide a tag for maintainers to pull the generic_handle_irq_safe() API.