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ecbd804752
We ripped out PV and virtualization related bits from rqspinlock in an earlier commit, however, a fair lock performs poorly within a virtual machine when the lock holder is preempted. As such, retain the virt_spin_lock fallback to test and set lock, but with timeout and deadlock detection. We can do this by simply depending on the resilient_tas_spin_lock implementation from the previous patch. We don't integrate support for CONFIG_PARAVIRT_SPINLOCKS yet, as that requires more involved algorithmic changes and introduces more complexity. It can be done when the need arises in the future. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20250316040541.108729-15-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
33 lines
847 B
C
33 lines
847 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_RQSPINLOCK_H
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#define _ASM_X86_RQSPINLOCK_H
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#include <asm/paravirt.h>
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#ifdef CONFIG_PARAVIRT
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DECLARE_STATIC_KEY_FALSE(virt_spin_lock_key);
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#define resilient_virt_spin_lock_enabled resilient_virt_spin_lock_enabled
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static __always_inline bool resilient_virt_spin_lock_enabled(void)
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{
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return static_branch_likely(&virt_spin_lock_key);
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}
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#ifdef CONFIG_QUEUED_SPINLOCKS
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typedef struct qspinlock rqspinlock_t;
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#else
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typedef struct rqspinlock rqspinlock_t;
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#endif
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extern int resilient_tas_spin_lock(rqspinlock_t *lock);
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#define resilient_virt_spin_lock resilient_virt_spin_lock
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static inline int resilient_virt_spin_lock(rqspinlock_t *lock)
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{
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return resilient_tas_spin_lock(lock);
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}
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#endif /* CONFIG_PARAVIRT */
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#include <asm-generic/rqspinlock.h>
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#endif /* _ASM_X86_RQSPINLOCK_H */
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