On 02 Aug 2014, at 16:10 , Alan Cox <a...@freebsd.org> wrote:
> Author: alc
> Date: Sat Aug 2 16:10:24 2014
> New Revision: 269433
> URL: http://svnweb.freebsd.org/changeset/base/269433
>
> Log:
> Handle wiring failures in vm_map_wire() with the new functions
> pmap_unwire() and vm_object_unwire().
>
> Retire vm_fault_{un,}wire(), since they are no longer used.
>
> (See r268327 and r269134 for the motivation behind this change.)
>
> Reviewed by: kib
> Sponsored by: EMC / Isilon Storage Division
>
cc1: warnings being treated as errors
/scratch/tmp/bz/head.svn/sys/vm/vm_map.c: In function 'vm_map_wire':
/scratch/tmp/bz/head.svn/sys/vm/vm_map.c:2470: warning: 'rv' may be used
uninitialized in this function
--- vm_map.o ---
*** [vm_map.o] Error code 1
> Modified:
> head/sys/vm/vm_extern.h
> head/sys/vm/vm_fault.c
> head/sys/vm/vm_map.c
>
> Modified: head/sys/vm/vm_extern.h
> ==============================================================================
> --- head/sys/vm/vm_extern.h Sat Aug 2 15:05:23 2014 (r269432)
> +++ head/sys/vm/vm_extern.h Sat Aug 2 16:10:24 2014 (r269433)
> @@ -81,7 +81,6 @@ int vm_fault_hold(vm_map_t map, vm_offse
> int fault_flags, vm_page_t *m_hold);
> int vm_fault_quick_hold_pages(vm_map_t map, vm_offset_t addr, vm_size_t len,
> vm_prot_t prot, vm_page_t *ma, int max_count);
> -int vm_fault_wire(vm_map_t, vm_offset_t, vm_offset_t, boolean_t);
> int vm_forkproc(struct thread *, struct proc *, struct thread *, struct
> vmspace *, int);
> void vm_waitproc(struct proc *);
> int vm_mmap(vm_map_t, vm_offset_t *, vm_size_t, vm_prot_t, vm_prot_t, int,
> objtype_t, void *, vm_ooffset_t);
>
> Modified: head/sys/vm/vm_fault.c
> ==============================================================================
> --- head/sys/vm/vm_fault.c Sat Aug 2 15:05:23 2014 (r269432)
> +++ head/sys/vm/vm_fault.c Sat Aug 2 16:10:24 2014 (r269433)
> @@ -106,7 +106,6 @@ __FBSDID("$FreeBSD$");
> #define PFFOR 4
>
> static int vm_fault_additional_pages(vm_page_t, int, int, vm_page_t *, int *);
> -static void vm_fault_unwire(vm_map_t, vm_offset_t, vm_offset_t, boolean_t);
>
> #define VM_FAULT_READ_BEHIND 8
> #define VM_FAULT_READ_MAX (1 + VM_FAULT_READ_AHEAD_MAX)
> @@ -1155,68 +1154,6 @@ error:
> }
>
> /*
> - * vm_fault_wire:
> - *
> - * Wire down a range of virtual addresses in a map.
> - */
> -int
> -vm_fault_wire(vm_map_t map, vm_offset_t start, vm_offset_t end,
> - boolean_t fictitious)
> -{
> - vm_offset_t va;
> - int rv;
> -
> - /*
> - * We simulate a fault to get the page and enter it in the physical
> - * map. For user wiring, we only ask for read access on currently
> - * read-only sections.
> - */
> - for (va = start; va < end; va += PAGE_SIZE) {
> - rv = vm_fault(map, va, VM_PROT_NONE, VM_FAULT_CHANGE_WIRING);
> - if (rv) {
> - if (va != start)
> - vm_fault_unwire(map, start, va, fictitious);
> - return (rv);
> - }
> - }
> - return (KERN_SUCCESS);
> -}
> -
> -/*
> - * vm_fault_unwire:
> - *
> - * Unwire a range of virtual addresses in a map.
> - */
> -static void
> -vm_fault_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end,
> - boolean_t fictitious)
> -{
> - vm_paddr_t pa;
> - vm_offset_t va;
> - vm_page_t m;
> - pmap_t pmap;
> -
> - pmap = vm_map_pmap(map);
> -
> - /*
> - * Since the pages are wired down, we must be able to get their
> - * mappings from the physical map system.
> - */
> - for (va = start; va < end; va += PAGE_SIZE) {
> - pa = pmap_extract(pmap, va);
> - if (pa != 0) {
> - pmap_change_wiring(pmap, va, FALSE);
> - if (!fictitious) {
> - m = PHYS_TO_VM_PAGE(pa);
> - vm_page_lock(m);
> - vm_page_unwire(m, PQ_ACTIVE);
> - vm_page_unlock(m);
> - }
> - }
> - }
> -}
> -
> -/*
> * Routine:
> * vm_fault_copy_entry
> * Function:
>
> Modified: head/sys/vm/vm_map.c
> ==============================================================================
> --- head/sys/vm/vm_map.c Sat Aug 2 15:05:23 2014 (r269432)
> +++ head/sys/vm/vm_map.c Sat Aug 2 16:10:24 2014 (r269433)
> @@ -140,6 +140,8 @@ static void vmspace_zdtor(void *mem, int
> static int vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos,
> vm_size_t max_ssize, vm_size_t growsize, vm_prot_t prot, vm_prot_t max,
> int cow);
> +static void vm_map_wire_entry_failure(vm_map_t map, vm_map_entry_t entry,
> + vm_offset_t failed_addr);
>
> #define ENTRY_CHARGED(e) ((e)->cred != NULL || \
> ((e)->object.vm_object != NULL && (e)->object.vm_object->cred != NULL && \
> @@ -2418,6 +2420,42 @@ done:
> }
>
> /*
> + * vm_map_wire_entry_failure:
> + *
> + * Handle a wiring failure on the given entry.
> + *
> + * The map should be locked.
> + */
> +static void
> +vm_map_wire_entry_failure(vm_map_t map, vm_map_entry_t entry,
> + vm_offset_t failed_addr)
> +{
> +
> + VM_MAP_ASSERT_LOCKED(map);
> + KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0 &&
> + entry->wired_count == 1,
> + ("vm_map_wire_entry_failure: entry %p isn't being wired", entry));
> + KASSERT(failed_addr < entry->end,
> + ("vm_map_wire_entry_failure: entry %p was fully wired", entry));
> +
> + /*
> + * If any pages at the start of this entry were successfully wired,
> + * then unwire them.
> + */
> + if (failed_addr > entry->start) {
> + pmap_unwire(map->pmap, entry->start, failed_addr);
> + vm_object_unwire(entry->object.vm_object, entry->offset,
> + failed_addr - entry->start, PQ_ACTIVE);
> + }
> +
> + /*
> + * Assign an out-of-range value to represent the failure to wire this
> + * entry.
> + */
> + entry->wired_count = -1;
> +}
> +
> +/*
> * vm_map_wire:
> *
> * Implements both kernel and user wiring.
> @@ -2427,10 +2465,10 @@ vm_map_wire(vm_map_t map, vm_offset_t st
> int flags)
> {
> vm_map_entry_t entry, first_entry, tmp_entry;
> - vm_offset_t saved_end, saved_start;
> + vm_offset_t faddr, saved_end, saved_start;
> unsigned int last_timestamp;
> int rv;
> - boolean_t fictitious, need_wakeup, result, user_wire;
> + boolean_t need_wakeup, result, user_wire;
> vm_prot_t prot;
>
> if (start == end)
> @@ -2523,17 +2561,24 @@ vm_map_wire(vm_map_t map, vm_offset_t st
> entry->wired_count++;
> saved_start = entry->start;
> saved_end = entry->end;
> - fictitious = entry->object.vm_object != NULL &&
> - (entry->object.vm_object->flags &
> - OBJ_FICTITIOUS) != 0;
> +
> /*
> * Release the map lock, relying on the in-transition
> * mark. Mark the map busy for fork.
> */
> vm_map_busy(map);
> vm_map_unlock(map);
> - rv = vm_fault_wire(map, saved_start, saved_end,
> - fictitious);
> +
> + for (faddr = saved_start; faddr < saved_end; faddr +=
> + PAGE_SIZE) {
> + /*
> + * Simulate a fault to get the page and enter
> + * it into the physical map.
> + */
> + if ((rv = vm_fault(map, faddr, VM_PROT_NONE,
> + VM_FAULT_CHANGE_WIRING)) != KERN_SUCCESS)
> + break;
> + }
> vm_map_lock(map);
> vm_map_unbusy(map);
> if (last_timestamp + 1 != map->timestamp) {
> @@ -2552,23 +2597,22 @@ vm_map_wire(vm_map_t map, vm_offset_t st
> first_entry = NULL;
> entry = tmp_entry;
> while (entry->end < saved_end) {
> - if (rv != KERN_SUCCESS) {
> - KASSERT(entry->wired_count == 1,
> - ("vm_map_wire: bad count"));
> - entry->wired_count = -1;
> - }
> + /*
> + * In case of failure, handle entries
> + * that were not fully wired here;
> + * fully wired entries are handled
> + * later.
> + */
> + if (rv != KERN_SUCCESS &&
> + faddr < entry->end)
> + vm_map_wire_entry_failure(map,
> + entry, faddr);
> entry = entry->next;
> }
> }
> last_timestamp = map->timestamp;
> if (rv != KERN_SUCCESS) {
> - KASSERT(entry->wired_count == 1,
> - ("vm_map_wire: bad count"));
> - /*
> - * Assign an out-of-range value to represent
> - * the failure to wire this entry.
> - */
> - entry->wired_count = -1;
> + vm_map_wire_entry_failure(map, entry, faddr);
> end = entry->end;
> goto done;
> }
> @@ -2632,6 +2676,10 @@ done:
> entry->wired_count = 0;
> } else if (!user_wire ||
> (entry->eflags & MAP_ENTRY_USER_WIRED) == 0) {
> + /*
> + * Undo the wiring. Wiring succeeded on this entry
> + * but failed on a later entry.
> + */
> if (entry->wired_count == 1)
> vm_map_entry_unwire(map, entry);
> else
>
—
Bjoern A. Zeeb "Come on. Learn, goddamn it.", WarGames, 1983
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