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Revision 85b144f860176ec18db927d6d9ecdfb24d9c6483 authored by Maarten Lankhorst on 29 November 2012, 11:36:54 UTC, committed by Dave Airlie on 10 December 2012, 10:21:03 UTC 
drm/ttm: call ttm_bo_cleanup_refs with reservation and lru lock held, v3
 
By removing the unlocking of lru and retaking it immediately, a race is
removed where the bo is taken off the swap list or the lru list between
the unlock and relock. As such the cleanup_refs code can be simplified,
it will attempt to call ttm_bo_wait non-blockingly, and if it fails
it will drop the locks and perform a blocking wait, or return an error
if no_wait_gpu was set.

The need for looping is also eliminated, since swapout and evict_mem_first
will always follow the destruction path, no new fence is allowed
to be attached. As far as I can see this may already have been the case,
but the unlocking / relocking required a complicated loop to deal with
re-reservation.

Changes since v1:
 - Simplify no_wait_gpu case by folding it in with empty ddestroy.
 - Hold a reservation while calling ttm_bo_cleanup_memtype_use again.
Changes since v2:
 - Do not remove bo from lru list while waiting

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
1 parent 6ed9ccb
Raw File
lglock.c 
/* See include/linux/lglock.h for description */
#include <linux/module.h>
#include <linux/lglock.h>
#include <linux/cpu.h>
#include <linux/string.h>

/*
 * Note there is no uninit, so lglocks cannot be defined in
 * modules (but it's fine to use them from there)
 * Could be added though, just undo lg_lock_init
 */

void lg_lock_init(struct lglock *lg, char *name)
{
	LOCKDEP_INIT_MAP(&lg->lock_dep_map, name, &lg->lock_key, 0);
}
EXPORT_SYMBOL(lg_lock_init);

void lg_local_lock(struct lglock *lg)
{
	arch_spinlock_t *lock;

	preempt_disable();
	rwlock_acquire_read(&lg->lock_dep_map, 0, 0, _RET_IP_);
	lock = this_cpu_ptr(lg->lock);
	arch_spin_lock(lock);
}
EXPORT_SYMBOL(lg_local_lock);

void lg_local_unlock(struct lglock *lg)
{
	arch_spinlock_t *lock;

	rwlock_release(&lg->lock_dep_map, 1, _RET_IP_);
	lock = this_cpu_ptr(lg->lock);
	arch_spin_unlock(lock);
	preempt_enable();
}
EXPORT_SYMBOL(lg_local_unlock);

void lg_local_lock_cpu(struct lglock *lg, int cpu)
{
	arch_spinlock_t *lock;

	preempt_disable();
	rwlock_acquire_read(&lg->lock_dep_map, 0, 0, _RET_IP_);
	lock = per_cpu_ptr(lg->lock, cpu);
	arch_spin_lock(lock);
}
EXPORT_SYMBOL(lg_local_lock_cpu);

void lg_local_unlock_cpu(struct lglock *lg, int cpu)
{
	arch_spinlock_t *lock;

	rwlock_release(&lg->lock_dep_map, 1, _RET_IP_);
	lock = per_cpu_ptr(lg->lock, cpu);
	arch_spin_unlock(lock);
	preempt_enable();
}
EXPORT_SYMBOL(lg_local_unlock_cpu);

void lg_global_lock(struct lglock *lg)
{
	int i;

	preempt_disable();
	rwlock_acquire(&lg->lock_dep_map, 0, 0, _RET_IP_);
	for_each_possible_cpu(i) {
		arch_spinlock_t *lock;
		lock = per_cpu_ptr(lg->lock, i);
		arch_spin_lock(lock);
	}
}
EXPORT_SYMBOL(lg_global_lock);

void lg_global_unlock(struct lglock *lg)
{
	int i;

	rwlock_release(&lg->lock_dep_map, 1, _RET_IP_);
	for_each_possible_cpu(i) {
		arch_spinlock_t *lock;
		lock = per_cpu_ptr(lg->lock, i);
		arch_spin_unlock(lock);
	}
	preempt_enable();
}
EXPORT_SYMBOL(lg_global_unlock);
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