Push Giant deep into vm_forkproc(), acquiring it only if the process has
mapped System V shared memory segments (see shmfork_myhook()) or requires the allocation of an ldt (see vm_fault_wire()).
This commit is contained in:
parent
2e3e26a50c
commit
94ddc7076d
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=134675
@ -219,9 +219,7 @@ fork1(td, flags, pages, procp)
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* certain parts of a process from itself.
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*/
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if ((flags & RFPROC) == 0) {
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mtx_lock(&Giant);
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vm_forkproc(td, NULL, NULL, flags);
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mtx_unlock(&Giant);
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/*
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* Close all file descriptors.
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@ -668,27 +666,25 @@ fork1(td, flags, pages, procp)
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* Finish creating the child process. It will return via a different
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* execution path later. (ie: directly into user mode)
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*/
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mtx_lock(&Giant);
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vm_forkproc(td, p2, td2, flags);
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if (flags == (RFFDG | RFPROC)) {
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cnt.v_forks++;
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cnt.v_forkpages += p2->p_vmspace->vm_dsize +
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p2->p_vmspace->vm_ssize;
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atomic_add_int(&cnt.v_forks, 1);
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atomic_add_int(&cnt.v_forkpages, p2->p_vmspace->vm_dsize +
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p2->p_vmspace->vm_ssize);
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} else if (flags == (RFFDG | RFPROC | RFPPWAIT | RFMEM)) {
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cnt.v_vforks++;
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cnt.v_vforkpages += p2->p_vmspace->vm_dsize +
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p2->p_vmspace->vm_ssize;
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atomic_add_int(&cnt.v_vforks, 1);
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atomic_add_int(&cnt.v_vforkpages, p2->p_vmspace->vm_dsize +
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p2->p_vmspace->vm_ssize);
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} else if (p1 == &proc0) {
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cnt.v_kthreads++;
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cnt.v_kthreadpages += p2->p_vmspace->vm_dsize +
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p2->p_vmspace->vm_ssize;
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atomic_add_int(&cnt.v_kthreads, 1);
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atomic_add_int(&cnt.v_kthreadpages, p2->p_vmspace->vm_dsize +
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p2->p_vmspace->vm_ssize);
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} else {
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cnt.v_rforks++;
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cnt.v_rforkpages += p2->p_vmspace->vm_dsize +
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p2->p_vmspace->vm_ssize;
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atomic_add_int(&cnt.v_rforks, 1);
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atomic_add_int(&cnt.v_rforkpages, p2->p_vmspace->vm_dsize +
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p2->p_vmspace->vm_ssize);
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}
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mtx_unlock(&Giant);
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/*
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* Both processes are set up, now check if any loadable modules want
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@ -806,6 +806,7 @@ shmfork_myhook(p1, p2)
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size_t size;
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int i;
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mtx_lock(&Giant);
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size = shminfo.shmseg * sizeof(struct shmmap_state);
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shmmap_s = malloc(size, M_SHM, M_WAITOK);
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bcopy(p1->p_vmspace->vm_shm, shmmap_s, size);
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@ -813,6 +814,7 @@ shmfork_myhook(p1, p2)
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for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
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if (shmmap_s->shmid != -1)
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shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
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mtx_unlock(&Giant);
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}
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static void
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@ -1026,9 +1026,13 @@ vm_fault_wire(vm_map_t map, vm_offset_t start, vm_offset_t end,
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* read-only sections.
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*/
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for (va = start; va < end; va += PAGE_SIZE) {
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if (map->system_map)
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mtx_lock(&Giant);
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rv = vm_fault(map, va,
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user_wire ? VM_PROT_READ : VM_PROT_READ | VM_PROT_WRITE,
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user_wire ? VM_FAULT_USER_WIRE : VM_FAULT_CHANGE_WIRING);
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if (map->system_map)
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mtx_unlock(&Giant);
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if (rv) {
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if (va != start)
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vm_fault_unwire(map, start, va, fictitious);
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@ -619,8 +619,6 @@ vm_forkproc(td, p2, td2, flags)
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{
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struct proc *p1 = td->td_proc;
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GIANT_REQUIRED;
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if ((flags & RFPROC) == 0) {
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/*
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* Divorce the memory, if it is shared, essentially
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@ -2482,8 +2482,6 @@ vmspace_fork(struct vmspace *vm1)
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vm_map_entry_t new_entry;
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vm_object_t object;
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GIANT_REQUIRED;
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vm_map_lock(old_map);
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vm2 = vmspace_alloc(old_map->min_offset, old_map->max_offset);
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@ -2942,7 +2940,6 @@ vmspace_unshare(struct proc *p)
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struct vmspace *oldvmspace = p->p_vmspace;
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struct vmspace *newvmspace;
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GIANT_REQUIRED;
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if (oldvmspace->vm_refcnt == 1)
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return;
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newvmspace = vmspace_fork(oldvmspace);
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