Messages in this thread Patch in this message | | | Date | Wed, 25 Jan 2023 11:39:12 -0000 | From | "tip-bot2 for Jens Axboe" <> | Subject | [tip: x86/fpu] x86/fpu: Don't set TIF_NEED_FPU_LOAD for PF_IO_WORKER threads |
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The following commit has been merged into the x86/fpu branch of tip:
Commit-ID: cb3ea4b7671b7cfbac3ee609976b790aebd0bbda Gitweb: https://git.kernel.org/tip/cb3ea4b7671b7cfbac3ee609976b790aebd0bbda Author: Jens Axboe <axboe@kernel.dk> AuthorDate: Tue, 24 Jan 2023 08:23:20 -07:00 Committer: Ingo Molnar <mingo@kernel.org> CommitterDate: Wed, 25 Jan 2023 12:35:15 +01:00
x86/fpu: Don't set TIF_NEED_FPU_LOAD for PF_IO_WORKER threads
We don't set it on PF_KTHREAD threads as they never return to userspace, and PF_IO_WORKER threads are identical in that regard. As they keep running in the kernel until they die, skip setting the FPU flag on them.
More of a cosmetic thing that was found while debugging and issue and pondering why the FPU flag is set on these threads.
Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/560c844c-f128-555b-40c6-31baff27537f@kernel.dk --- arch/x86/include/asm/fpu/sched.h | 2 +- arch/x86/kernel/fpu/context.h | 2 +- arch/x86/kernel/fpu/core.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/fpu/sched.h b/arch/x86/include/asm/fpu/sched.h index b2486b2..c2d6cd7 100644 --- a/arch/x86/include/asm/fpu/sched.h +++ b/arch/x86/include/asm/fpu/sched.h @@ -39,7 +39,7 @@ extern void fpu_flush_thread(void); static inline void switch_fpu_prepare(struct fpu *old_fpu, int cpu) { if (cpu_feature_enabled(X86_FEATURE_FPU) && - !(current->flags & PF_KTHREAD)) { + !(current->flags & (PF_KTHREAD | PF_IO_WORKER))) { save_fpregs_to_fpstate(old_fpu); /* * The save operation preserved register state, so the diff --git a/arch/x86/kernel/fpu/context.h b/arch/x86/kernel/fpu/context.h index 958accf..9fcfa5c 100644 --- a/arch/x86/kernel/fpu/context.h +++ b/arch/x86/kernel/fpu/context.h @@ -57,7 +57,7 @@ static inline void fpregs_restore_userregs(void) struct fpu *fpu = ¤t->thread.fpu; int cpu = smp_processor_id(); - if (WARN_ON_ONCE(current->flags & PF_KTHREAD)) + if (WARN_ON_ONCE(current->flags & (PF_KTHREAD | PF_IO_WORKER))) return; if (!fpregs_state_valid(fpu, cpu)) { diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 9baa89a..2babc53 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -426,7 +426,7 @@ void kernel_fpu_begin_mask(unsigned int kfpu_mask) this_cpu_write(in_kernel_fpu, true); - if (!(current->flags & PF_KTHREAD) && + if (!(current->flags & (PF_KTHREAD | PF_IO_WORKER)) && !test_thread_flag(TIF_NEED_FPU_LOAD)) { set_thread_flag(TIF_NEED_FPU_LOAD); save_fpregs_to_fpstate(¤t->thread.fpu);
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