e48c15b796
This commit adds a destination CPU to __call_single_data, and is inspired by an earlier commit by Peter Zijlstra. This version adds #ifdef to permit use by 32-bit systems and supplying the destination CPU for all smp_call_function*() requests, not just smp_call_function_single(). If need be, 32-bit systems could be accommodated by shrinking the flags field to 16 bits (the atomic_t variant is currently unused) and by providing only eight bits for CPU on such systems. It is not clear that the addition of the fields to __call_single_node are really needed. [ paulmck: Apply Boqun Feng feedback on 32-bit builds. ] Link: https://lore.kernel.org/lkml/20200615164048.GC2531@hirez.programming.kicks-ass.net/ Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
70 lines
1.3 KiB
C
70 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_SMP_TYPES_H
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#define __LINUX_SMP_TYPES_H
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#include <linux/llist.h>
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enum {
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CSD_FLAG_LOCK = 0x01,
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IRQ_WORK_PENDING = 0x01,
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IRQ_WORK_BUSY = 0x02,
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IRQ_WORK_LAZY = 0x04, /* No IPI, wait for tick */
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IRQ_WORK_HARD_IRQ = 0x08, /* IRQ context on PREEMPT_RT */
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IRQ_WORK_CLAIMED = (IRQ_WORK_PENDING | IRQ_WORK_BUSY),
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CSD_TYPE_ASYNC = 0x00,
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CSD_TYPE_SYNC = 0x10,
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CSD_TYPE_IRQ_WORK = 0x20,
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CSD_TYPE_TTWU = 0x30,
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CSD_FLAG_TYPE_MASK = 0xF0,
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};
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/*
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* struct __call_single_node is the primary type on
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* smp.c:call_single_queue.
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*
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* flush_smp_call_function_queue() only reads the type from
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* __call_single_node::u_flags as a regular load, the above
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* (anonymous) enum defines all the bits of this word.
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*
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* Other bits are not modified until the type is known.
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*
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* CSD_TYPE_SYNC/ASYNC:
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* struct {
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* struct llist_node node;
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* unsigned int flags;
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* smp_call_func_t func;
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* void *info;
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* };
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*
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* CSD_TYPE_IRQ_WORK:
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* struct {
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* struct llist_node node;
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* atomic_t flags;
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* void (*func)(struct irq_work *);
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* };
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*
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* CSD_TYPE_TTWU:
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* struct {
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* struct llist_node node;
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* unsigned int flags;
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* };
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*
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*/
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struct __call_single_node {
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struct llist_node llist;
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union {
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unsigned int u_flags;
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atomic_t a_flags;
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};
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#ifdef CONFIG_64BIT
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u16 src, dst;
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#endif
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};
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#endif /* __LINUX_SMP_TYPES_H */
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