Date: Fri, 7 Dec 2018 16:22:54 +0000 (UTC) From: Mateusz Guzik <mjg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r341699 - head/sys/vm Message-ID: <201812071622.wB7GMsUo072168@repo.freebsd.org>
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Author: mjg Date: Fri Dec 7 16:22:54 2018 New Revision: 341699 URL: https://svnweb.freebsd.org/changeset/base/341699 Log: vm: use fcmpset for vmspace reference counting Sponsored by: The FreeBSD Foundation Modified: head/sys/vm/vm_map.c Modified: head/sys/vm/vm_map.c ============================================================================== --- head/sys/vm/vm_map.c Fri Dec 7 16:11:45 2018 (r341698) +++ head/sys/vm/vm_map.c Fri Dec 7 16:22:54 2018 (r341699) @@ -391,8 +391,8 @@ vmspace_exit(struct thread *td) p = td->td_proc; vm = p->p_vmspace; atomic_add_int(&vmspace0.vm_refcnt, 1); + refcnt = vm->vm_refcnt; do { - refcnt = vm->vm_refcnt; if (refcnt > 1 && p->p_vmspace != &vmspace0) { /* Switch now since other proc might free vmspace */ PROC_VMSPACE_LOCK(p); @@ -400,7 +400,7 @@ vmspace_exit(struct thread *td) PROC_VMSPACE_UNLOCK(p); pmap_activate(td); } - } while (!atomic_cmpset_int(&vm->vm_refcnt, refcnt, refcnt - 1)); + } while (!atomic_fcmpset_int(&vm->vm_refcnt, &refcnt, refcnt - 1)); if (refcnt == 1) { if (p->p_vmspace != vm) { /* vmspace not yet freed, switch back */ @@ -437,13 +437,13 @@ vmspace_acquire_ref(struct proc *p) PROC_VMSPACE_UNLOCK(p); return (NULL); } + refcnt = vm->vm_refcnt; do { - refcnt = vm->vm_refcnt; if (refcnt <= 0) { /* Avoid 0->1 transition */ PROC_VMSPACE_UNLOCK(p); return (NULL); } - } while (!atomic_cmpset_int(&vm->vm_refcnt, refcnt, refcnt + 1)); + } while (!atomic_fcmpset_int(&vm->vm_refcnt, &refcnt, refcnt + 1)); if (vm != p->p_vmspace) { PROC_VMSPACE_UNLOCK(p); vmspace_free(vm);
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