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cec199c5e3
Extend the futex2 interface to be numa aware.
When FUTEX2_NUMA is specified for a futex, the user value is extended
to two words (of the same size). The first is the user value we all
know, the second one will be the node to place this futex on.
struct futex_numa_32 {
u32 val;
u32 node;
};
When node is set to ~0, WAIT will set it to the current node_id such
that WAKE knows where to find it. If userspace corrupts the node value
between WAIT and WAKE, the futex will not be found and no wakeup will
happen.
When FUTEX2_NUMA is not set, the node is simply an extension of the
hash, such that traditional futexes are still interleaved over the
nodes.
This is done to avoid having to have a separate !numa hash-table.
[bigeasy: ensure to have at least hashsize of 4 in futex_init(), add
pr_info() for size and allocation information. Cast the naddr math to
void*]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250416162921.513656-17-bigeasy@linutronix.de
126 lines
3.4 KiB
C
126 lines
3.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_FUTEX_H
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#define _LINUX_FUTEX_H
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#include <linux/sched.h>
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#include <linux/ktime.h>
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#include <linux/mm_types.h>
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#include <uapi/linux/futex.h>
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struct inode;
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struct task_struct;
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/*
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* Futexes are matched on equal values of this key.
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* The key type depends on whether it's a shared or private mapping.
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* Don't rearrange members without looking at hash_futex().
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*
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* offset is aligned to a multiple of sizeof(u32) (== 4) by definition.
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* We use the two low order bits of offset to tell what is the kind of key :
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* 00 : Private process futex (PTHREAD_PROCESS_PRIVATE)
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* (no reference on an inode or mm)
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* 01 : Shared futex (PTHREAD_PROCESS_SHARED)
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* mapped on a file (reference on the underlying inode)
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* 10 : Shared futex (PTHREAD_PROCESS_SHARED)
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* (but private mapping on an mm, and reference taken on it)
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*/
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#define FUT_OFF_INODE 1 /* We set bit 0 if key has a reference on inode */
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#define FUT_OFF_MMSHARED 2 /* We set bit 1 if key has a reference on mm */
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union futex_key {
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struct {
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u64 i_seq;
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unsigned long pgoff;
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unsigned int offset;
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/* unsigned int node; */
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} shared;
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struct {
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union {
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struct mm_struct *mm;
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u64 __tmp;
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};
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unsigned long address;
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unsigned int offset;
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/* unsigned int node; */
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} private;
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struct {
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u64 ptr;
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unsigned long word;
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unsigned int offset;
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unsigned int node; /* NOT hashed! */
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} both;
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};
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#define FUTEX_KEY_INIT (union futex_key) { .both = { .ptr = 0ULL } }
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#ifdef CONFIG_FUTEX
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enum {
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FUTEX_STATE_OK,
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FUTEX_STATE_EXITING,
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FUTEX_STATE_DEAD,
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};
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static inline void futex_init_task(struct task_struct *tsk)
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{
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tsk->robust_list = NULL;
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#ifdef CONFIG_COMPAT
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tsk->compat_robust_list = NULL;
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#endif
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INIT_LIST_HEAD(&tsk->pi_state_list);
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tsk->pi_state_cache = NULL;
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tsk->futex_state = FUTEX_STATE_OK;
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mutex_init(&tsk->futex_exit_mutex);
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}
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void futex_exit_recursive(struct task_struct *tsk);
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void futex_exit_release(struct task_struct *tsk);
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void futex_exec_release(struct task_struct *tsk);
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long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
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u32 __user *uaddr2, u32 val2, u32 val3);
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int futex_hash_prctl(unsigned long arg2, unsigned long arg3, unsigned long arg4);
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#ifdef CONFIG_FUTEX_PRIVATE_HASH
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int futex_hash_allocate_default(void);
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void futex_hash_free(struct mm_struct *mm);
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static inline void futex_mm_init(struct mm_struct *mm)
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{
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rcu_assign_pointer(mm->futex_phash, NULL);
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mutex_init(&mm->futex_hash_lock);
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}
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#else /* !CONFIG_FUTEX_PRIVATE_HASH */
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static inline int futex_hash_allocate_default(void) { return 0; }
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static inline void futex_hash_free(struct mm_struct *mm) { }
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static inline void futex_mm_init(struct mm_struct *mm) { }
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#endif /* CONFIG_FUTEX_PRIVATE_HASH */
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#else /* !CONFIG_FUTEX */
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static inline void futex_init_task(struct task_struct *tsk) { }
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static inline void futex_exit_recursive(struct task_struct *tsk) { }
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static inline void futex_exit_release(struct task_struct *tsk) { }
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static inline void futex_exec_release(struct task_struct *tsk) { }
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static inline long do_futex(u32 __user *uaddr, int op, u32 val,
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ktime_t *timeout, u32 __user *uaddr2,
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u32 val2, u32 val3)
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{
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return -EINVAL;
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}
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static inline int futex_hash_prctl(unsigned long arg2, unsigned long arg3, unsigned long arg4)
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{
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return -EINVAL;
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}
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static inline int futex_hash_allocate_default(void)
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{
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return 0;
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}
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static inline void futex_hash_free(struct mm_struct *mm) { }
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static inline void futex_mm_init(struct mm_struct *mm) { }
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#endif
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#endif
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