[src/netbsd-1-6]: src/sys/uvm Pull up revision 1.45 (requested by skrll):

[tron <tron%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/99e66eb523fb
branches:  netbsd-1-6
changeset: 530232:99e66eb523fb
user:      tron <tron%NetBSD.org@localhost>
date:      Mon Jun 02 14:30:18 2003 +0000

description:
Pull up revision 1.45 (requested by skrll):
add a new km flag UVM_KMF_CANFAIL, which causes uvm_km_kmemalloc() to
return failure if swap is full and there are no free physical pages.
have malloc() use this flag if M_CANFAIL is passed to it.
use M_CANFAIL to allow amap_extend() to fail when memory is scarce.
this should prevent most of the remaining hangs in low-memory situations.

diffstat:

 sys/uvm/uvm_amap.c |  53 ++++++++++++++++++++++++++++++++++-------------------
 1 files changed, 34 insertions(+), 19 deletions(-)

diffs (133 lines):

diff -r 5371118b510b -r 99e66eb523fb sys/uvm/uvm_amap.c
--- a/sys/uvm/uvm_amap.c        Mon Jun 02 14:30:10 2003 +0000
+++ b/sys/uvm/uvm_amap.c        Mon Jun 02 14:30:18 2003 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_amap.c,v 1.43 2002/03/28 06:06:29 nathanw Exp $    */
+/*     $NetBSD: uvm_amap.c,v 1.43.4.1 2003/06/02 14:30:18 tron Exp $   */
 
 /*
  *
@@ -42,7 +42,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_amap.c,v 1.43 2002/03/28 06:06:29 nathanw Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_amap.c,v 1.43.4.1 2003/06/02 14:30:18 tron Exp $");
 
 #undef UVM_AMAP_INLINE         /* enable/disable amap inlines */
 
@@ -282,10 +282,8 @@
  * => amap should be unlocked (we will lock it)
  * => to safely extend an amap it should have a reference count of
  *    one (thus it can't be shared)
- * => XXXCDC: needs a waitflag or failure return value?
- * => XXXCDC: support padding at this level?
  */
-void
+int
 amap_extend(entry, addsize)
        struct vm_map_entry *entry;
        vsize_t addsize;
@@ -308,8 +306,7 @@
         * there are some unused slots before us in the amap.
         */
 
-       amap_lock(amap);                                        /* lock! */
-
+       amap_lock(amap);
        AMAP_B2SLOT(slotmapped, entry->end - entry->start); /* slots mapped */
        AMAP_B2SLOT(slotadd, addsize);                  /* slots to add */
        slotneed = slotoff + slotmapped + slotadd;
@@ -329,13 +326,14 @@
                amap_unlock(amap);
                UVMHIST_LOG(maphist,"<- done (case 1), amap = 0x%x, sltneed=%d",
                    amap, slotneed, 0, 0);
-               return;                         /* done! */
+               return 0;
        }
 
        /*
         * case 2: we pre-allocated slots for use and we just need to
         * bump nslot up to take account for these slots.
         */
+
        if (amap->am_maxslot >= slotneed) {
 #ifdef UVM_AMAP_PPREF
                if (amap->am_ppref && amap->am_ppref != PPREF_NONE) {
@@ -349,13 +347,15 @@
 #endif
                amap->am_nslot = slotneed;
                amap_unlock(amap);
+
                /*
                 * no need to zero am_anon since that was done at
                 * alloc time and we never shrink an allocation.
                 */
-               UVMHIST_LOG(maphist,"<- done (case 2), amap = 0x%x, slotneed=%d",
-                   amap, slotneed, 0, 0);
-               return;
+
+               UVMHIST_LOG(maphist,"<- done (case 2), amap = 0x%x, "
+                   "slotneed=%d", amap, slotneed, 0, 0);
+               return 0;
        }
 
        /*
@@ -371,19 +371,32 @@
        newppref = NULL;
        if (amap->am_ppref && amap->am_ppref != PPREF_NONE) {
                newppref = malloc(slotalloc * sizeof(int), M_UVMAMAP,
-                   M_NOWAIT);
+                   M_WAITOK | M_CANFAIL);
                if (newppref == NULL) {
-                       /* give up if malloc fails */
                        free(amap->am_ppref, M_UVMAMAP);
                        amap->am_ppref = PPREF_NONE;
                }
        }
 #endif
-       newsl = malloc(slotalloc * sizeof(int), M_UVMAMAP, M_WAITOK);
-       newbck = malloc(slotalloc * sizeof(int), M_UVMAMAP, M_WAITOK);
-       newover = malloc(slotalloc * sizeof(struct vm_anon *),
-           M_UVMAMAP, M_WAITOK);
-       amap_lock(amap);                        /* re-lock! */
+       newsl = malloc(slotalloc * sizeof(int), M_UVMAMAP,
+           M_WAITOK | M_CANFAIL);
+       newbck = malloc(slotalloc * sizeof(int), M_UVMAMAP,
+           M_WAITOK | M_CANFAIL);
+       newover = malloc(slotalloc * sizeof(struct vm_anon *), M_UVMAMAP,
+           M_WAITOK | M_CANFAIL);
+       if (newsl == NULL || newbck == NULL || newover == NULL) {
+               if (newsl != NULL) {
+                       free(newsl, M_UVMAMAP);
+               }
+               if (newbck != NULL) {
+                       free(newbck, M_UVMAMAP);
+               }
+               if (newover != NULL) {
+                       free(newover, M_UVMAMAP);
+               }
+               return ENOMEM;
+       }
+       amap_lock(amap);
        KASSERT(amap->am_maxslot < slotneed);
 
        /*
@@ -400,7 +413,8 @@
        /* do am_anon */
        oldover = amap->am_anon;
        memcpy(newover, oldover, sizeof(struct vm_anon *) * amap->am_nslot);
-       memset(newover + amap->am_nslot, 0, sizeof(struct vm_anon *) * slotadded);
+       memset(newover + amap->am_nslot, 0, sizeof(struct vm_anon *) *
+           slotadded);
        amap->am_anon = newover;
 
        /* do am_bckptr */
@@ -437,6 +451,7 @@
 #endif
        UVMHIST_LOG(maphist,"<- done (case 3), amap = 0x%x, slotneed=%d",
            amap, slotneed, 0, 0);
+       return 0;
 }
 
 /*