| Message ID | 20230510162406.1955-2-jszhang@kernel.org (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | riscv: add PREEMPT_RT support | expand |
| Context | Check | Description |
|---|---|---|
| conchuod/cover_letter | success | Series has a cover letter |
| conchuod/tree_selection | success | Guessed tree name to be for-next at HEAD ac9a78681b92 |
| conchuod/fixes_present | success | Fixes tag not required for -next series |
| conchuod/maintainers_pattern | success | MAINTAINERS pattern errors before the patch: 6 and now 6 |
| conchuod/verify_signedoff | success | Signed-off-by tag matches author and committer |
| conchuod/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| conchuod/build_rv64_clang_allmodconfig | success | Errors and warnings before: 2849 this patch: 2849 |
| conchuod/module_param | success | Was 0 now: 0 |
| conchuod/build_rv64_gcc_allmodconfig | success | Errors and warnings before: 16380 this patch: 16380 |
| conchuod/build_rv32_defconfig | success | Build OK |
| conchuod/dtb_warn_rv64 | success | Errors and warnings before: 3 this patch: 3 |
| conchuod/header_inline | success | No static functions without inline keyword in header files |
| conchuod/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 26 lines checked |
| conchuod/build_rv64_nommu_k210_defconfig | success | Build OK |
| conchuod/verify_fixes | success | No Fixes tag |
| conchuod/build_rv64_nommu_virt_defconfig | success | Build OK |
diff --git a/include/asm-generic/preempt.h b/include/asm-generic/preempt.h index b4d43a4af5f7..b583e7c38ccf 100644 --- a/include/asm-generic/preempt.h +++ b/include/asm-generic/preempt.h @@ -59,6 +59,11 @@ static __always_inline void __preempt_count_sub(int val) *preempt_count_ptr() -= val; } +#ifdef CONFIG_PREEMPT_LAZY +#define preempt_lazy_count() (current_thread_info()->preempt_lazy_count) +#else +#define preempt_lazy_count() (0) +#endif static __always_inline bool __preempt_count_dec_and_test(void) { /* @@ -66,7 +71,7 @@ static __always_inline bool __preempt_count_dec_and_test(void) * operations; we cannot use PREEMPT_NEED_RESCHED because it might get * lost. */ - return !--*preempt_count_ptr() && tif_need_resched(); + return !--*preempt_count_ptr() && !preempt_lazy_count() && tif_need_resched(); } /* @@ -75,6 +80,7 @@ static __always_inline bool __preempt_count_dec_and_test(void) static __always_inline bool should_resched(int preempt_offset) { return unlikely(preempt_count() == preempt_offset && + !preempt_lazy_count() && tif_need_resched()); }
lazy preempt count is great mechanism to help ordinary SCHED_OTHER tasks' throughput Under PREEMPT_RT. But current implementation relies on each arch-specific code to check the preempt_lazy_count in should_resched() and __preempt_count_dec_and_test(), if the arch, e.g riscv use the asm-generic preempt implementation, it losts the great lazy preempt mechanism. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> --- include/asm-generic/preempt.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)