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7de9d4f946
Start to flesh out the real find_proxy_task() implementation, but avoid the migration cases for now, in those cases just deactivate the donor task and pick again. To ensure the donor task or other blocked tasks in the chain aren't migrated away while we're running the proxy, also tweak the fair class logic to avoid migrating donor or mutex blocked tasks. [jstultz: This change was split out from the larger proxy patch] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Connor O'Brien <connoro@google.com> Signed-off-by: John Stultz <jstultz@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: K Prateek Nayak <kprateek.nayak@amd.com> Link: https://lkml.kernel.org/r/20250712033407.2383110-9-jstultz@google.com
73 lines
2.5 KiB
C
73 lines
2.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Mutexes: blocking mutual exclusion locks
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*
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* started by Ingo Molnar:
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*
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* Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
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*/
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#ifndef CONFIG_PREEMPT_RT
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/*
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* This is the control structure for tasks blocked on mutex, which resides
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* on the blocked task's kernel stack:
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*/
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struct mutex_waiter {
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struct list_head list;
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struct task_struct *task;
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struct ww_acquire_ctx *ww_ctx;
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#ifdef CONFIG_DEBUG_MUTEXES
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void *magic;
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#endif
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};
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/*
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* @owner: contains: 'struct task_struct *' to the current lock owner,
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* NULL means not owned. Since task_struct pointers are aligned at
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* at least L1_CACHE_BYTES, we have low bits to store extra state.
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*
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* Bit0 indicates a non-empty waiter list; unlock must issue a wakeup.
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* Bit1 indicates unlock needs to hand the lock to the top-waiter
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* Bit2 indicates handoff has been done and we're waiting for pickup.
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*/
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#define MUTEX_FLAG_WAITERS 0x01
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#define MUTEX_FLAG_HANDOFF 0x02
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#define MUTEX_FLAG_PICKUP 0x04
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#define MUTEX_FLAGS 0x07
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/*
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* Internal helper function; C doesn't allow us to hide it :/
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*
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* DO NOT USE (outside of mutex & scheduler code).
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*/
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static inline struct task_struct *__mutex_owner(struct mutex *lock)
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{
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if (!lock)
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return NULL;
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return (struct task_struct *)(atomic_long_read(&lock->owner) & ~MUTEX_FLAGS);
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}
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#ifdef CONFIG_DEBUG_MUTEXES
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extern void debug_mutex_lock_common(struct mutex *lock,
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struct mutex_waiter *waiter);
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extern void debug_mutex_wake_waiter(struct mutex *lock,
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struct mutex_waiter *waiter);
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extern void debug_mutex_free_waiter(struct mutex_waiter *waiter);
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extern void debug_mutex_add_waiter(struct mutex *lock,
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struct mutex_waiter *waiter,
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struct task_struct *task);
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extern void debug_mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
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struct task_struct *task);
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extern void debug_mutex_unlock(struct mutex *lock);
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extern void debug_mutex_init(struct mutex *lock, const char *name,
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struct lock_class_key *key);
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#else /* CONFIG_DEBUG_MUTEXES */
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# define debug_mutex_lock_common(lock, waiter) do { } while (0)
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# define debug_mutex_wake_waiter(lock, waiter) do { } while (0)
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# define debug_mutex_free_waiter(waiter) do { } while (0)
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# define debug_mutex_add_waiter(lock, waiter, ti) do { } while (0)
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# define debug_mutex_remove_waiter(lock, waiter, ti) do { } while (0)
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# define debug_mutex_unlock(lock) do { } while (0)
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# define debug_mutex_init(lock, name, key) do { } while (0)
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#endif /* !CONFIG_DEBUG_MUTEXES */
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#endif /* CONFIG_PREEMPT_RT */
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