From: Jisheng Zhang <jszhang@kernel.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Thomas Gleixner <tglx@linutronix.de>,
Schaffner Tobias <tobias.schaffner@siemens.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>, Arnd Bergmann <arnd@arndb.de>
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org
Subject: [PATCH RT 2/3] riscv: add lazy preempt support
Date: Thu, 11 May 2023 00:24:05 +0800 [thread overview]
Message-ID: <20230510162406.1955-3-jszhang@kernel.org> (raw)
In-Reply-To: <20230510162406.1955-1-jszhang@kernel.org>
Implement the lazy preempt for riscv.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
arch/riscv/Kconfig | 1 +
arch/riscv/include/asm/thread_info.h | 5 ++++-
arch/riscv/kernel/asm-offsets.c | 1 +
3 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 348c0fa1fc8c..89e9d9fb35c4 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -118,6 +118,7 @@ config RISCV
select HAVE_PERF_REGS
select HAVE_PERF_USER_STACK_DUMP
select HAVE_POSIX_CPU_TIMERS_TASK_WORK
+ select HAVE_PREEMPT_LAZY
select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_RSEQ
select HAVE_STACKPROTECTOR
diff --git a/arch/riscv/include/asm/thread_info.h b/arch/riscv/include/asm/thread_info.h
index e0d202134b44..c5e9223e9b91 100644
--- a/arch/riscv/include/asm/thread_info.h
+++ b/arch/riscv/include/asm/thread_info.h
@@ -59,6 +59,7 @@ extern unsigned long spin_shadow_stack;
struct thread_info {
unsigned long flags; /* low level flags */
int preempt_count; /* 0=>preemptible, <0=>BUG */
+ int preempt_lazy_count; /* 0=>preemptible, <0=>BUG */
/*
* These stack pointers are overwritten on every system call or
* exception. SP is also saved to the stack it can be recovered when
@@ -90,6 +91,7 @@ struct thread_info {
* - pending work-to-be-done flags are in lowest half-word
* - other flags in upper half-word(s)
*/
+#define TIF_NEED_RESCHED_LAZY 0 /* lazy rescheduling */
#define TIF_NOTIFY_RESUME 1 /* callback before returning to user */
#define TIF_SIGPENDING 2 /* signal pending */
#define TIF_NEED_RESCHED 3 /* rescheduling necessary */
@@ -104,9 +106,10 @@ struct thread_info {
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
#define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL)
#define _TIF_UPROBE (1 << TIF_UPROBE)
+#define _TIF_NEED_RESCHED_LAZY (1 << TIF_NEED_RESCHED_LAZY)
#define _TIF_WORK_MASK \
(_TIF_NOTIFY_RESUME | _TIF_SIGPENDING | _TIF_NEED_RESCHED | \
- _TIF_NOTIFY_SIGNAL | _TIF_UPROBE)
+ _TIF_NEED_RESCHED_LAZY | _TIF_NOTIFY_SIGNAL | _TIF_UPROBE)
#endif /* _ASM_RISCV_THREAD_INFO_H */
diff --git a/arch/riscv/kernel/asm-offsets.c b/arch/riscv/kernel/asm-offsets.c
index d6a75aac1d27..1f8cccacb44e 100644
--- a/arch/riscv/kernel/asm-offsets.c
+++ b/arch/riscv/kernel/asm-offsets.c
@@ -36,6 +36,7 @@ void asm_offsets(void)
OFFSET(TASK_THREAD_S11, task_struct, thread.s[11]);
OFFSET(TASK_TI_FLAGS, task_struct, thread_info.flags);
OFFSET(TASK_TI_PREEMPT_COUNT, task_struct, thread_info.preempt_count);
+ OFFSET(TASK_TI_PREEMPT_LAZY_COUNT, task_struct, thread_info.preempt_lazy_count);
OFFSET(TASK_TI_KERNEL_SP, task_struct, thread_info.kernel_sp);
OFFSET(TASK_TI_USER_SP, task_struct, thread_info.user_sp);
--
2.40.1
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next prev parent reply other threads:[~2023-05-10 16:35 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-10 16:24 [PATCH RT 0/3] riscv: add PREEMPT_RT support Jisheng Zhang
2023-05-10 16:24 ` [PATCH RT 1/3] asm-generic/preempt: also check preempt_lazy_count for should_resched() etc Jisheng Zhang
2023-05-10 16:24 ` Jisheng Zhang [this message]
2023-05-10 16:24 ` [PATCH RT 3/3] riscv: Allow to enable RT Jisheng Zhang
2023-10-23 16:33 ` [PATCH RT 0/3] riscv: add PREEMPT_RT support Schaffner, Tobias
2023-10-23 16:40 ` Jisheng Zhang
2023-10-24 6:18 ` Sebastian Andrzej Siewior
2023-10-31 14:43 ` Jisheng Zhang
2023-10-31 15:34 ` Sebastian Andrzej Siewior
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