Avoid resource deadlocks when one domain has exhausted its memory. Attempt
other allowed domains if the requested domain is below the minimum paging threshold. Block in fork only if all domains available to the forking thread are below the severe threshold rather than any. Submitted by: jeff Reported by: mjg Reviewed by: alc, kib, markj Approved by: re (rgrimes) Differential Revision: https://reviews.freebsd.org/D16191
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parent
0c0c965a8f
commit
23984ce5cd
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=338507
@ -187,6 +187,13 @@ vm_page_count_severe(void)
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return (!DOMAINSET_EMPTY(&vm_severe_domains));
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}
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static inline int
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vm_page_count_severe_set(domainset_t *mask)
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{
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return (DOMAINSET_SUBSET(&vm_severe_domains, mask));
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}
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/*
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* Return TRUE if we are under our minimum low-free-pages threshold.
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*
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@ -100,6 +100,8 @@ vm_domainset_iter_init(struct vm_domainset_iter *di, struct vm_object *obj,
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pindex += (((uintptr_t)obj) / sizeof(*obj));
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di->di_offset = pindex;
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}
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/* Skip zones below min on the first pass. */
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di->di_minskip = true;
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}
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static void
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@ -213,6 +215,8 @@ vm_domainset_iter_page_init(struct vm_domainset_iter *di, struct vm_object *obj,
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*req = (di->di_flags & ~(VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL)) |
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VM_ALLOC_NOWAIT;
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vm_domainset_iter_first(di, domain);
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if (DOMAINSET_ISSET(*domain, &vm_min_domains))
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vm_domainset_iter_page(di, domain, req);
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}
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int
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@ -227,8 +231,15 @@ vm_domainset_iter_page(struct vm_domainset_iter *di, int *domain, int *req)
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return (ENOMEM);
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/* If there are more domains to visit we run the iterator. */
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if (--di->di_n != 0) {
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while (--di->di_n != 0) {
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vm_domainset_iter_next(di, domain);
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if (!di->di_minskip ||
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!DOMAINSET_ISSET(*domain, &vm_min_domains))
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return (0);
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}
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if (di->di_minskip) {
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di->di_minskip = false;
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vm_domainset_iter_first(di, domain);
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return (0);
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}
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@ -258,6 +269,8 @@ vm_domainset_iter_malloc_init(struct vm_domainset_iter *di,
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di->di_flags = *flags;
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*flags = (di->di_flags & ~M_WAITOK) | M_NOWAIT;
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vm_domainset_iter_first(di, domain);
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if (DOMAINSET_ISSET(*domain, &vm_min_domains))
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vm_domainset_iter_malloc(di, domain, flags);
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}
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int
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@ -265,8 +278,17 @@ vm_domainset_iter_malloc(struct vm_domainset_iter *di, int *domain, int *flags)
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{
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/* If there are more domains to visit we run the iterator. */
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if (--di->di_n != 0) {
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while (--di->di_n != 0) {
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vm_domainset_iter_next(di, domain);
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if (!di->di_minskip ||
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!DOMAINSET_ISSET(*domain, &vm_min_domains))
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return (0);
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}
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/* If we skipped zones below min start the search from the beginning. */
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if (di->di_minskip) {
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di->di_minskip = false;
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vm_domainset_iter_first(di, domain);
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return (0);
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}
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@ -34,9 +34,10 @@ struct vm_domainset_iter {
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struct domainset *di_domain;
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int *di_iter;
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vm_pindex_t di_offset;
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int di_policy;
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int di_flags;
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int di_n;
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uint16_t di_policy;
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domainid_t di_n;
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bool di_minskip;
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};
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int vm_domainset_iter_page(struct vm_domainset_iter *, int *, int *);
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@ -46,4 +47,6 @@ int vm_domainset_iter_malloc(struct vm_domainset_iter *, int *, int *);
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void vm_domainset_iter_malloc_init(struct vm_domainset_iter *,
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struct vm_object *, int *, int *);
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void vm_wait_doms(const domainset_t *);
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#endif /* __VM_DOMAINSET_H__ */
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@ -548,6 +548,7 @@ vm_fault_hold(vm_map_t map, vm_offset_t vaddr, vm_prot_t fault_type,
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{
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struct faultstate fs;
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struct vnode *vp;
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struct domainset *dset;
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vm_object_t next_object, retry_object;
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vm_offset_t e_end, e_start;
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vm_pindex_t retry_pindex;
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@ -791,7 +792,11 @@ RetryFault:;
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* there, and allocation can fail, causing
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* restart and new reading of the p_flag.
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*/
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if (!vm_page_count_severe() || P_KILLED(curproc)) {
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dset = fs.object->domain.dr_policy;
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if (dset == NULL)
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dset = curthread->td_domain.dr_policy;
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if (!vm_page_count_severe_set(&dset->ds_mask) ||
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P_KILLED(curproc)) {
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#if VM_NRESERVLEVEL > 0
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vm_object_color(fs.object, atop(vaddr) -
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fs.pindex);
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@ -806,7 +811,7 @@ RetryFault:;
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}
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if (fs.m == NULL) {
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unlock_and_deallocate(&fs);
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vm_waitpfault();
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vm_waitpfault(dset);
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goto RetryFault;
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}
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}
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@ -92,6 +92,7 @@ __FBSDID("$FreeBSD$");
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/pmap.h>
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#include <vm/vm_domainset.h>
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#include <vm/vm_map.h>
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#include <vm/vm_page.h>
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#include <vm/vm_pageout.h>
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@ -534,6 +535,7 @@ vm_forkproc(struct thread *td, struct proc *p2, struct thread *td2,
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struct vmspace *vm2, int flags)
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{
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struct proc *p1 = td->td_proc;
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struct domainset *dset;
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int error;
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if ((flags & RFPROC) == 0) {
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@ -557,9 +559,9 @@ vm_forkproc(struct thread *td, struct proc *p2, struct thread *td2,
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p2->p_vmspace = p1->p_vmspace;
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atomic_add_int(&p1->p_vmspace->vm_refcnt, 1);
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}
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while (vm_page_count_severe()) {
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vm_wait_severe();
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dset = td2->td_domain.dr_policy;
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while (vm_page_count_severe_set(&dset->ds_mask)) {
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vm_wait_doms(&dset->ds_mask);
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}
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if ((flags & RFMEM) == 0) {
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@ -2935,7 +2935,7 @@ vm_wait_count(void)
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return (vm_severe_waiters + vm_min_waiters + vm_pageproc_waiters);
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}
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static void
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void
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vm_wait_doms(const domainset_t *wdoms)
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{
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@ -2961,10 +2961,10 @@ vm_wait_doms(const domainset_t *wdoms)
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mtx_lock(&vm_domainset_lock);
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if (DOMAINSET_SUBSET(&vm_min_domains, wdoms)) {
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vm_min_waiters++;
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msleep(&vm_min_domains, &vm_domainset_lock, PVM,
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"vmwait", 0);
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}
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mtx_unlock(&vm_domainset_lock);
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msleep(&vm_min_domains, &vm_domainset_lock,
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PVM | PDROP, "vmwait", 0);
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} else
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mtx_unlock(&vm_domainset_lock);
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}
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}
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@ -3069,15 +3069,21 @@ vm_domain_alloc_fail(struct vm_domain *vmd, vm_object_t object, int req)
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* this balance without careful testing first.
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*/
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void
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vm_waitpfault(void)
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vm_waitpfault(struct domainset *dset)
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{
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/*
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* XXX Ideally we would wait only until the allocation could
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* be satisfied. This condition can cause new allocators to
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* consume all freed pages while old allocators wait.
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*/
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mtx_lock(&vm_domainset_lock);
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if (vm_page_count_min()) {
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if (DOMAINSET_SUBSET(&vm_min_domains, &dset->ds_mask)) {
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vm_min_waiters++;
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msleep(&vm_min_domains, &vm_domainset_lock, PUSER, "pfault", 0);
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}
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mtx_unlock(&vm_domainset_lock);
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msleep(&vm_min_domains, &vm_domainset_lock, PUSER | PDROP,
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"pfault", 0);
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} else
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mtx_unlock(&vm_domainset_lock);
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}
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struct vm_pagequeue *
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*/
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void vm_wait(vm_object_t obj);
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void vm_waitpfault(void);
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void vm_waitpfault(struct domainset *);
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void vm_wait_domain(int domain);
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void vm_wait_min(void);
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void vm_wait_severe(void);
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