On 02 Aug 2014, at 17:03 , Alan Cox <a...@rice.edu> wrote:
> On 08/02/2014 11:54, Bjoern A. Zeeb wrote:
>> 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
>
> gcc?
>
mips, powerpc, sparc64, arm; yeah very likely.
>>
>>
>>> 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
>>
>>
>
—
Bjoern A. Zeeb "Come on. Learn, goddamn it.", WarGames, 1983
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