int
memory_object_control_uiomove(
memory_object_control_t control,
memory_object_offset_t offset,
void * uio,
int start_offset,
int io_requested,
int mark_dirty,
int take_reference)
{
vm_object_t object;
vm_page_t dst_page;
int xsize;
int retval = 0;
int cur_run;
int cur_needed;
int i;
int orig_offset;
boolean_t make_lru = FALSE;
vm_page_t page_run[MAX_RUN];
object = memory_object_control_to_vm_object(control);
if (object == VM_OBJECT_NULL) {
return (0);
}
assert(!object->internal);
vm_object_lock(object);
if (mark_dirty && object->copy != VM_OBJECT_NULL) {
/*
* We can't modify the pages without honoring
* copy-on-write obligations first, so fall off
* this optimized path and fall back to the regular
* path.
*/
vm_object_unlock(object);
return 0;
}
orig_offset = start_offset;
while (io_requested && retval == 0) {
cur_needed = (start_offset + io_requested + (PAGE_SIZE - 1)) / PAGE_SIZE;
if (cur_needed > MAX_RUN)
cur_needed = MAX_RUN;
for (cur_run = 0; cur_run < cur_needed; ) {
if ((dst_page = vm_page_lookup(object, offset)) == VM_PAGE_NULL)
break;
/*
* Sync up on getting the busy bit
*/
if ((dst_page->busy || dst_page->cleaning)) {
/*
* someone else is playing with the page... if we've
* already collected pages into this run, go ahead
* and process now, we can't block on this
* page while holding other pages in the BUSY state
* otherwise we will wait
*/
if (cur_run)
break;
PAGE_SLEEP(object, dst_page, THREAD_UNINT);
continue;
}
/*
* this routine is only called when copying
* to/from real files... no need to consider
* encrypted swap pages
*/
assert(!dst_page->encrypted);
if (mark_dirty) {
dst_page->dirty = TRUE;
if (dst_page->cs_validated) {
/*
* CODE SIGNING:
* We're modifying a code-signed
* page: assume that it is now tainted.
*/
dst_page->cs_tainted = TRUE;
vm_cs_tainted_forces++;
}
}
dst_page->busy = TRUE;
page_run[cur_run++] = dst_page;
offset += PAGE_SIZE_64;
}
if (cur_run == 0)
/*
* we hit a 'hole' in the cache
* we bail at this point
* we'll unlock the object below
*/
break;
vm_object_unlock(object);
for (i = 0; i < cur_run; i++) {
dst_page = page_run[i];
if ((xsize = PAGE_SIZE - start_offset) > io_requested)
xsize = io_requested;
if ( (retval = uiomove64((addr64_t)(((addr64_t)(dst_page->phys_page) << 12) + start_offset), xsize, uio)) )
break;
io_requested -= xsize;
start_offset = 0;
}
vm_object_lock(object);
/*
* if we have more than 1 page to work on
* in the current run, or the original request
* started at offset 0 of the page, or we're
* processing multiple batches, we will move
* the pages to the tail of the inactive queue
* to implement an LRU for read/write accesses
*
* the check for orig_offset == 0 is there to
* mitigate the cost of small (< page_size) requests
* to the same page (this way we only move it once)
*/
if (take_reference && (cur_run > 1 || orig_offset == 0)) {
vm_page_lockspin_queues();
make_lru = TRUE;
}
for (i = 0; i < cur_run; i++) {
dst_page = page_run[i];
/*
* someone is explicitly referencing this page...
* update clustered and speculative state
*
*/
VM_PAGE_CONSUME_CLUSTERED(dst_page);
if (make_lru == TRUE)
vm_page_lru(dst_page);
PAGE_WAKEUP_DONE(dst_page);
}
if (make_lru == TRUE) {
vm_page_unlock_queues();
make_lru = FALSE;
}
orig_offset = 0;
}
vm_object_unlock(object);
return (retval);
}
int
memory_object_control_uiomove(
memory_object_control_t control,
memory_object_offset_t offset,
void * uio,
int start_offset,
int io_requested,
int mark_dirty,
int take_reference)
{
vm_object_t object;
vm_page_t dst_page;
int xsize;
int retval = 0;
int cur_run;
int cur_needed;
int i;
int orig_offset;
vm_page_t page_run[MAX_RUN];
object = memory_object_control_to_vm_object(control);
if (object == VM_OBJECT_NULL) {
return (0);
}
assert(!object->internal);
vm_object_lock(object);
if (mark_dirty && object->copy != VM_OBJECT_NULL) {
/*
* We can't modify the pages without honoring
* copy-on-write obligations first, so fall off
* this optimized path and fall back to the regular
* path.
*/
vm_object_unlock(object);
return 0;
}
orig_offset = start_offset;
while (io_requested && retval == 0) {
cur_needed = (start_offset + io_requested + (PAGE_SIZE - 1)) / PAGE_SIZE;
if (cur_needed > MAX_RUN)
cur_needed = MAX_RUN;
for (cur_run = 0; cur_run < cur_needed; ) {
if ((dst_page = vm_page_lookup(object, offset)) == VM_PAGE_NULL)
break;
/*
* if we're in this routine, we are inside a filesystem's
* locking model, so we don't ever want to wait for pages that have
* list_req_pending == TRUE since it means that the
* page is a candidate for some type of I/O operation,
* but that it has not yet been gathered into a UPL...
* this implies that it is still outside the domain
* of the filesystem and that whoever is responsible for
* grabbing it into a UPL may be stuck behind the filesystem
* lock this thread owns, or trying to take a lock exclusively
* and waiting for the readers to drain from a rw lock...
* if we block in those cases, we will deadlock
*/
if (dst_page->list_req_pending) {
if (dst_page->absent) {
/*
* this is the list_req_pending | absent | busy case
* which originates from vm_fault_page... we want
* to fall out of the fast path and go back
* to the caller which will gather this page
* into a UPL and issue the I/O if no one
* else beats us to it
*/
break;
}
if (dst_page->pageout || dst_page->cleaning) {
/*
* this is the list_req_pending | pageout | busy case
* or the list_req_pending | cleaning case...
* which originate from the pageout_scan and
* msync worlds for the pageout case and the hibernate
* pre-cleaning world for the cleaning case...
* we need to reset the state of this page to indicate
* it should stay in the cache marked dirty... nothing else we
* can do at this point... we can't block on it, we can't busy
* it and we can't clean it from this routine.
*/
vm_page_lockspin_queues();
vm_pageout_queue_steal(dst_page, TRUE);
vm_page_deactivate(dst_page);
vm_page_unlock_queues();
}
/*
* this is the list_req_pending | cleaning case...
* we can go ahead and deal with this page since
* its ok for us to mark this page busy... if a UPL
* tries to gather this page, it will block until the
* busy is cleared, thus allowing us safe use of the page
* when we're done with it, we will clear busy and wake
* up anyone waiting on it, thus allowing the UPL creation
* to finish
*/
} else if (dst_page->busy || dst_page->cleaning) {
/*
* someone else is playing with the page... if we've
* already collected pages into this run, go ahead
* and process now, we can't block on this
* page while holding other pages in the BUSY state
* otherwise we will wait
*/
if (cur_run)
break;
PAGE_SLEEP(object, dst_page, THREAD_UNINT);
continue;
}
/*
* this routine is only called when copying
* to/from real files... no need to consider
* encrypted swap pages
*/
assert(!dst_page->encrypted);
if (mark_dirty) {
dst_page->dirty = TRUE;
if (dst_page->cs_validated &&
!dst_page->cs_tainted) {
/*
* CODE SIGNING:
* We're modifying a code-signed
* page: force revalidate
*/
dst_page->cs_validated = FALSE;
#if DEVELOPMENT || DEBUG
vm_cs_validated_resets++;
#endif
pmap_disconnect(dst_page->phys_page);
}
}
dst_page->busy = TRUE;
page_run[cur_run++] = dst_page;
offset += PAGE_SIZE_64;
}
if (cur_run == 0)
/*
* we hit a 'hole' in the cache or
* a page we don't want to try to handle,
* so bail at this point
* we'll unlock the object below
*/
break;
vm_object_unlock(object);
for (i = 0; i < cur_run; i++) {
dst_page = page_run[i];
if ((xsize = PAGE_SIZE - start_offset) > io_requested)
xsize = io_requested;
if ( (retval = uiomove64((addr64_t)(((addr64_t)(dst_page->phys_page) << 12) + start_offset), xsize, uio)) )
break;
io_requested -= xsize;
start_offset = 0;
}
vm_object_lock(object);
/*
* if we have more than 1 page to work on
* in the current run, or the original request
* started at offset 0 of the page, or we're
* processing multiple batches, we will move
* the pages to the tail of the inactive queue
* to implement an LRU for read/write accesses
*
* the check for orig_offset == 0 is there to
* mitigate the cost of small (< page_size) requests
* to the same page (this way we only move it once)
*/
if (take_reference && (cur_run > 1 || orig_offset == 0)) {
vm_page_lockspin_queues();
for (i = 0; i < cur_run; i++)
vm_page_lru(page_run[i]);
vm_page_unlock_queues();
}
for (i = 0; i < cur_run; i++) {
dst_page = page_run[i];
/*
* someone is explicitly referencing this page...
* update clustered and speculative state
*
*/
VM_PAGE_CONSUME_CLUSTERED(dst_page);
PAGE_WAKEUP_DONE(dst_page);
}
orig_offset = 0;
}
vm_object_unlock(object);
return (retval);
}