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Diffstat (limited to 'sys/uvm/uvm_fault.c')
-rw-r--r--sys/uvm/uvm_fault.c84
1 files changed, 59 insertions, 25 deletions
diff --git a/sys/uvm/uvm_fault.c b/sys/uvm/uvm_fault.c
index bf1bfcd32a6..a4d0337d469 100644
--- a/sys/uvm/uvm_fault.c
+++ b/sys/uvm/uvm_fault.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: uvm_fault.c,v 1.118 2021/03/12 14:15:49 jsg Exp $ */
+/* $OpenBSD: uvm_fault.c,v 1.119 2021/03/20 10:24:21 mpi Exp $ */
/* $NetBSD: uvm_fault.c,v 1.51 2000/08/06 00:22:53 thorpej Exp $ */
/*
@@ -230,24 +230,32 @@ static void
uvmfault_amapcopy(struct uvm_faultinfo *ufi)
{
for (;;) {
- /* no mapping? give up. */
+ /*
+ * no mapping? give up.
+ */
if (uvmfault_lookup(ufi, TRUE) == FALSE)
return;
- /* copy if needed. */
+ /*
+ * copy if needed.
+ */
if (UVM_ET_ISNEEDSCOPY(ufi->entry))
amap_copy(ufi->map, ufi->entry, M_NOWAIT,
UVM_ET_ISSTACK(ufi->entry) ? FALSE : TRUE,
ufi->orig_rvaddr, ufi->orig_rvaddr + 1);
- /* didn't work? must be out of RAM. sleep. */
+ /*
+ * didn't work? must be out of RAM. unlock and sleep.
+ */
if (UVM_ET_ISNEEDSCOPY(ufi->entry)) {
uvmfault_unlockmaps(ufi, TRUE);
uvm_wait("fltamapcopy");
continue;
}
- /* got it! */
+ /*
+ * got it! unlock and return.
+ */
uvmfault_unlockmaps(ufi, TRUE);
return;
}
@@ -341,11 +349,11 @@ uvmfault_anonget(struct uvm_faultinfo *ufi, struct vm_amap *amap,
uvmfault_unlockall(ufi, amap, NULL);
/*
- * we are passing a PG_BUSY+PG_FAKE+PG_CLEAN
- * page into the uvm_swap_get function with
- * all data structures unlocked. note that
- * it is ok to read an_swslot here because
- * we hold PG_BUSY on the page.
+ * Pass a PG_BUSY+PG_FAKE+PG_CLEAN page into
+ * the uvm_swap_get() function with all data
+ * structures unlocked. Note that it is OK
+ * to read an_swslot here, because we hold
+ * PG_BUSY on the page.
*/
counters_inc(uvmexp_counters, pageins);
error = uvm_swap_get(pg, anon->an_swslot,
@@ -393,6 +401,9 @@ uvmfault_anonget(struct uvm_faultinfo *ufi, struct vm_amap *amap,
if (pg->pg_flags & PG_RELEASED) {
pmap_page_protect(pg, PROT_NONE);
KASSERT(anon->an_ref == 0);
+ /*
+ * Released while we had unlocked amap.
+ */
if (locked)
uvmfault_unlockall(ufi, NULL, NULL);
uvm_anon_release(anon); /* frees page for us */
@@ -418,7 +429,7 @@ uvmfault_anonget(struct uvm_faultinfo *ufi, struct vm_amap *amap,
/*
* Note: page was never !PG_BUSY, so it
* cannot be mapped and thus no need to
- * pmap_page_protect it...
+ * pmap_page_protect() it.
*/
uvm_lock_pageq();
uvm_pagefree(pg);
@@ -432,8 +443,7 @@ uvmfault_anonget(struct uvm_faultinfo *ufi, struct vm_amap *amap,
}
/*
- * must be OK, clear modify (already PG_CLEAN)
- * and activate
+ * We have successfully read the page, activate it.
*/
pmap_clear_modify(pg);
uvm_lock_pageq();
@@ -776,7 +786,9 @@ uvm_fault_check(struct uvm_faultinfo *ufi, struct uvm_faultctx *flt,
if (amap)
uvmfault_anonflush(*ranons, nback);
- /* flush object? */
+ /*
+ * flush object?
+ */
if (uobj) {
voff_t uoff;
@@ -843,7 +855,7 @@ uvm_fault_upper_lookup(struct uvm_faultinfo *ufi,
}
/*
- * unmapped or center page. check if any anon at this level.
+ * unmapped or center page. check if any anon at this level.
*/
if (amap == NULL || anons[lcv] == NULL) {
pages[lcv] = NULL;
@@ -903,6 +915,7 @@ uvm_fault_upper(struct uvm_faultinfo *ufi, struct uvm_faultctx *flt,
struct vm_page *pg = NULL;
int error, ret;
+ /* locked: maps(read), amap, anon */
KASSERT(rw_write_held(amap->am_lock));
KASSERT(anon->an_lock == amap->am_lock);
@@ -1037,7 +1050,9 @@ uvm_fault_upper(struct uvm_faultinfo *ufi, struct uvm_faultctx *flt,
return ERESTART;
}
- /* ... update the page queues. */
+ /*
+ * ... update the page queues.
+ */
uvm_lock_pageq();
if (fault_type == VM_FAULT_WIRE) {
@@ -1181,6 +1196,7 @@ uvm_fault_lower(struct uvm_faultinfo *ufi, struct uvm_faultctx *flt,
* (PGO_LOCKED).
*/
if (uobj == NULL) {
+ /* zero fill; don't care neighbor pages */
uobjpage = NULL;
} else {
uobjpage = uvm_fault_lower_lookup(ufi, flt, pages);
@@ -1236,7 +1252,9 @@ uvm_fault_lower(struct uvm_faultinfo *ufi, struct uvm_faultctx *flt,
0, flt->access_type & MASK(ufi->entry), ufi->entry->advice,
PGO_SYNCIO);
- /* recover from I/O */
+ /*
+ * recover from I/O
+ */
if (result != VM_PAGER_OK) {
KASSERT(result != VM_PAGER_PEND);
@@ -1343,7 +1361,9 @@ uvm_fault_lower(struct uvm_faultinfo *ufi, struct uvm_faultctx *flt,
* out of memory resources?
*/
if (anon == NULL || pg == NULL) {
- /* arg! must unbusy our page and fail or sleep. */
+ /*
+ * arg! must unbusy our page and fail or sleep.
+ */
if (uobjpage != PGO_DONTCARE) {
uvm_lock_pageq();
uvm_pageactivate(uobjpage);
@@ -1378,7 +1398,9 @@ uvm_fault_lower(struct uvm_faultinfo *ufi, struct uvm_faultctx *flt,
return ERESTART;
}
- /* fill in the data */
+ /*
+ * fill in the data
+ */
if (uobjpage != PGO_DONTCARE) {
counters_inc(uvmexp_counters, flt_prcopy);
/* copy page [pg now dirty] */
@@ -1559,9 +1581,12 @@ uvm_fault_unwire_locked(vm_map_t map, vaddr_t start, vaddr_t end)
* the PAs from the pmap. we also lock out the page daemon so that
* we can call uvm_pageunwire.
*/
+
uvm_lock_pageq();
- /* find the beginning map entry for the region. */
+ /*
+ * find the beginning map entry for the region.
+ */
KASSERT(start >= vm_map_min(map) && end <= vm_map_max(map));
if (uvm_map_lookup_entry(map, start, &entry) == FALSE)
panic("uvm_fault_unwire_locked: address not in map");
@@ -1570,7 +1595,9 @@ uvm_fault_unwire_locked(vm_map_t map, vaddr_t start, vaddr_t end)
if (pmap_extract(pmap, va, &pa) == FALSE)
continue;
- /* find the map entry for the current address. */
+ /*
+ * find the map entry for the current address.
+ */
KASSERT(va >= entry->start);
while (va >= entry->end) {
next = RBT_NEXT(uvm_map_addr, entry);
@@ -1578,7 +1605,9 @@ uvm_fault_unwire_locked(vm_map_t map, vaddr_t start, vaddr_t end)
entry = next;
}
- /* if the entry is no longer wired, tell the pmap. */
+ /*
+ * if the entry is no longer wired, tell the pmap.
+ */
if (VM_MAPENT_ISWIRED(entry) == 0)
pmap_unwire(pmap, va);
@@ -1646,7 +1675,9 @@ uvmfault_lookup(struct uvm_faultinfo *ufi, boolean_t write_lock)
{
vm_map_t tmpmap;
- /* init ufi values for lookup. */
+ /*
+ * init ufi values for lookup.
+ */
ufi->map = ufi->orig_map;
ufi->size = ufi->orig_size;
@@ -1688,11 +1719,14 @@ uvmfault_lookup(struct uvm_faultinfo *ufi, boolean_t write_lock)
continue;
}
- /* got it! */
+ /*
+ * got it!
+ */
ufi->mapv = ufi->map->timestamp;
return(TRUE);
- }
+ } /* while loop */
+
/*NOTREACHED*/
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-30 02:07:55 +0000