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Drop the object lock earlier in fault and don't relock it after pmap_enter().

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Recent changes in object and page locking have enabled more lock pushdown.

Reviewed by:	kib
Tested by:	pho
Differential Revision:	https://reviews.freebsd.org/D22036
This commit is contained in:
jeff 2019-10-29 20:46:25 +00:00
parent d122abaabb
commit e367407259
1 changed files with 12 additions and 5 deletions
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17
sys/vm/vm_fault.c
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@ -184,11 +184,10 @@ unlock_vp(struct faultstate *fs)
}
static void
unlock_and_deallocate(struct faultstate *fs)
fault_deallocate(struct faultstate *fs)
{
vm_object_pip_wakeup(fs->object);
VM_OBJECT_WUNLOCK(fs->object);
if (fs->object != fs->first_object) {
VM_OBJECT_WLOCK(fs->first_object);
vm_page_free(fs->first_m);
@ -201,6 +200,14 @@ unlock_and_deallocate(struct faultstate *fs)
unlock_vp(fs);
}
static void
unlock_and_deallocate(struct faultstate *fs)
{
VM_OBJECT_WUNLOCK(fs->object);
fault_deallocate(fs);
}
static void
vm_fault_dirty(vm_map_entry_t entry, vm_page_t m, vm_prot_t prot,
vm_prot_t fault_type, int fault_flags, bool set_wd)
@ -1261,10 +1268,12 @@ vm_fault(vm_map_t map, vm_offset_t vaddr, vm_prot_t fault_type,
fs.object, OFF_TO_IDX(
fs.first_object->backing_object_offset));
#endif
VM_OBJECT_WUNLOCK(fs.object);
fs.first_m = fs.m;
fs.m = NULL;
VM_CNT_INC(v_cow_optim);
} else {
VM_OBJECT_WUNLOCK(fs.object);
/*
* Oh, well, lets copy it.
*/
@ -1285,7 +1294,6 @@ vm_fault(vm_map_t map, vm_offset_t vaddr, vm_prot_t fault_type,
* conditional
*/
vm_object_pip_wakeup(fs.object);
VM_OBJECT_WUNLOCK(fs.object);
/*
* We only try to prefault read-only mappings to the
@ -1405,7 +1413,6 @@ vm_fault(vm_map_t map, vm_offset_t vaddr, vm_prot_t fault_type,
vm_fault_prefault(&fs, vaddr,
faultcount > 0 ? behind : PFBAK,
faultcount > 0 ? ahead : PFFOR, false);
VM_OBJECT_WLOCK(fs.object);
/*
* If the page is not wired down, then put it where the pageout daemon
@ -1427,7 +1434,7 @@ vm_fault(vm_map_t map, vm_offset_t vaddr, vm_prot_t fault_type,
/*
* Unlock everything, and return
*/
unlock_and_deallocate(&fs);
fault_deallocate(&fs);
if (hardfault) {
VM_CNT_INC(v_io_faults);
curthread->td_ru.ru_majflt++;