diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2025-05-03 16:38:56 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-05-04 10:29:25 +0200 |
| commit | 016a2e6f8ae5ed544ba8fb2b6d78f64ddfd9d01b (patch) | |
| tree | 690053c7f761f4cf72c2478e824377916043aad2 | |
| parent | 2d299e3d773d519ee93e5aaa3ffddd4a6276b005 (diff) | |
x86/fpu: Check TIF_NEED_FPU_LOAD instead of PF_KTHREAD|PF_USER_WORKER in fpu__drop()
PF_KTHREAD|PF_USER_WORKER tasks should never clear TIF_NEED_FPU_LOAD,
so the TIF_NEED_FPU_LOAD check should equally filter them out.
And this way an exiting userspace task can avoid the unnecessary "fwait"
if it does context_switch() at least once on its way to exit_thread().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Chang S . Bae <chang.seok.bae@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250503143856.GA9009@redhat.com
| -rw-r--r-- | arch/x86/kernel/fpu/core.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 8d674435f173..fa131299c7da 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -693,8 +693,7 @@ void fpu__drop(struct task_struct *tsk) { struct fpu *fpu; - /* PF_KTHREAD tasks do not use the FPU context area: */ - if (tsk->flags & (PF_KTHREAD | PF_USER_WORKER)) + if (test_tsk_thread_flag(tsk, TIF_NEED_FPU_LOAD)) return; fpu = x86_task_fpu(tsk); |