path: root/arch/csky
diff options
authorLinus Torvalds <>2020-12-16 12:33:35 -0800
committerLinus Torvalds <>2020-12-16 12:33:35 -0800
commit005b2a9dc819a1265a8c765595f8f6d88d6173d9 (patch)
tree688107572f6b3e017fc7ccf54f552c6a30441a79 /arch/csky
parent5ee863bec794f30bdf7fdf57ce0d9f579b0d1aa3 (diff)
parent355fb9e2b78e78b38ec00f5cd9b05c6aceb98335 (diff)
Merge tag 'tif-task_work.arch-2020-12-14' of git://
Pull TIF_NOTIFY_SIGNAL updates from Jens Axboe: "This sits on top of of the core entry/exit and x86 entry branch from the tip tree, which contains the generic and x86 parts of this work. Here we convert the rest of the archs to support TIF_NOTIFY_SIGNAL. With that done, we can get rid of JOBCTL_TASK_WORK from task_work and signal.c, and also remove a deadlock work-around in io_uring around knowing that signal based task_work waking is invoked with the sighand wait queue head lock. The motivation for this work is to decouple signal notify based task_work, of which io_uring is a heavy user of, from sighand. The sighand lock becomes a huge contention point, particularly for threaded workloads where it's shared between threads. Even outside of threaded applications it's slower than it needs to be. Roman Gershman <> reported that his networked workload dropped from 1.6M QPS at 80% CPU to 1.0M QPS at 100% CPU after io_uring was changed to use TIF_NOTIFY_SIGNAL. The time was all spent hammering on the sighand lock, showing 57% of the CPU time there [1]. There are further cleanups possible on top of this. One example is TIF_PATCH_PENDING, where a patch already exists to use TIF_NOTIFY_SIGNAL instead. Hopefully this will also lead to more consolidation, but the work stands on its own as well" [1] * tag 'tif-task_work.arch-2020-12-14' of git:// (28 commits) io_uring: remove 'twa_signal_ok' deadlock work-around kernel: remove checking for TIF_NOTIFY_SIGNAL signal: kill JOBCTL_TASK_WORK io_uring: JOBCTL_TASK_WORK is no longer used by task_work task_work: remove legacy TWA_SIGNAL path sparc: add support for TIF_NOTIFY_SIGNAL riscv: add support for TIF_NOTIFY_SIGNAL nds32: add support for TIF_NOTIFY_SIGNAL ia64: add support for TIF_NOTIFY_SIGNAL h8300: add support for TIF_NOTIFY_SIGNAL c6x: add support for TIF_NOTIFY_SIGNAL alpha: add support for TIF_NOTIFY_SIGNAL xtensa: add support for TIF_NOTIFY_SIGNAL arm: add support for TIF_NOTIFY_SIGNAL microblaze: add support for TIF_NOTIFY_SIGNAL hexagon: add support for TIF_NOTIFY_SIGNAL csky: add support for TIF_NOTIFY_SIGNAL openrisc: add support for TIF_NOTIFY_SIGNAL sh: add support for TIF_NOTIFY_SIGNAL um: add support for TIF_NOTIFY_SIGNAL ...
Diffstat (limited to 'arch/csky')
2 files changed, 5 insertions, 2 deletions
diff --git a/arch/csky/include/asm/thread_info.h b/arch/csky/include/asm/thread_info.h
index 68e7a1227170..21456a3737c2 100644
--- a/arch/csky/include/asm/thread_info.h
+++ b/arch/csky/include/asm/thread_info.h
@@ -64,6 +64,7 @@ static inline struct thread_info *current_thread_info(void)
#define TIF_SYSCALL_TRACE 4 /* syscall trace active */
#define TIF_SYSCALL_TRACEPOINT 5 /* syscall tracepoint instrumentation */
#define TIF_SYSCALL_AUDIT 6 /* syscall auditing */
+#define TIF_NOTIFY_SIGNAL 7 /* signal notifications exist */
#define TIF_POLLING_NRFLAG 16 /* poll_idle() is TIF_NEED_RESCHED */
#define TIF_MEMDIE 18 /* is terminating due to OOM killer */
#define TIF_RESTORE_SIGMASK 20 /* restore signal mask in do_signal() */
@@ -75,6 +76,7 @@ static inline struct thread_info *current_thread_info(void)
#define _TIF_UPROBE (1 << TIF_UPROBE)
#define _TIF_MEMDIE (1 << TIF_MEMDIE)
@@ -82,7 +84,8 @@ static inline struct thread_info *current_thread_info(void)
diff --git a/arch/csky/kernel/signal.c b/arch/csky/kernel/signal.c
index 8b068cf37447..37ea64ed3c12 100644
--- a/arch/csky/kernel/signal.c
+++ b/arch/csky/kernel/signal.c
@@ -257,7 +257,7 @@ asmlinkage void do_notify_resume(struct pt_regs *regs,
/* Handle pending signal delivery */
- if (thread_info_flags & _TIF_SIGPENDING)
+ if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
if (thread_info_flags & _TIF_NOTIFY_RESUME) {