From: Andrei Vagin <[email protected]>
seccomp_unotify allows more privileged processes do actions on behalf
of less privileged processes.
In many cases, the workflow is fully synchronous. It means a target
process triggers a system call and passes controls to a supervisor
process that handles the system call and returns controls back to the
target process. In this context, "synchronous" means that only one
process is running and another one is waiting.
The new WF_CURRENT_CPU flag advises the scheduler to move the wakee to
the current CPU. For such synchronous workflows, it makes context
switches a few times faster.
Right now, each interaction takes 12µs. With this patch, it takes about
3µs.
v2: clean up the first patch and add the test.
v3: update commit messages and a few fixes suggested by Kees Cook.
Kees is ready to take this patch set, but wants to get Acks from the
sched folks.
Cc: Andy Lutomirski <[email protected]>
Cc: Christian Brauner <[email protected]>
Cc: Dietmar Eggemann <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Peter Oskolkov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Tycho Andersen <[email protected]>
Cc: Will Drewry <[email protected]>
Cc: Vincent Guittot <[email protected]>
Andrei Vagin (4):
seccomp: don't use semaphore and wait_queue together
sched: add a few helpers to wake up tasks on the current cpu
seccomp: add the synchronous mode for seccomp_unotify
selftest/seccomp: add a new test for the sync mode of
seccomp_user_notify
Peter Oskolkov (1):
sched: add WF_CURRENT_CPU and externise ttwu
include/linux/completion.h | 1 +
include/linux/swait.h | 1 +
include/linux/wait.h | 3 +
include/uapi/linux/seccomp.h | 4 +
kernel/sched/completion.c | 12 +++
kernel/sched/core.c | 5 +-
kernel/sched/fair.c | 4 +
kernel/sched/sched.h | 13 +--
kernel/sched/swait.c | 11 +++
kernel/sched/wait.c | 5 ++
kernel/seccomp.c | 72 +++++++++++++--
tools/testing/selftests/seccomp/seccomp_bpf.c | 88 +++++++++++++++++++
12 files changed, 204 insertions(+), 15 deletions(-)
--
2.37.2