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in amap_pp_adjref(), avoid unnecessary fragmentation of the am_ppref array 

by merging the first changed chunk with the last unchanged chunk if possible.
This commit is contained in:
chs 2002-02-25 00:39:16 +00:00
parent 41e1be38c5
commit 811c8fad2b
1 changed files with 17 additions and 9 deletions
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26
sys/uvm/uvm_amap.c
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@ -1,4 +1,4 @@
/* $NetBSD: uvm_amap.c,v 1.40 2001/12/05 01:33:09 enami Exp $ */ /* $NetBSD: uvm_amap.c,v 1.41 2002/02/25 00:39:16 chs Exp $ */
/* /*
* *
@ -42,7 +42,7 @@
*/ */
#include <sys/cdefs.h> #include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: uvm_amap.c,v 1.40 2001/12/05 01:33:09 enami Exp $"); __KERNEL_RCSID(0, "$NetBSD: uvm_amap.c,v 1.41 2002/02/25 00:39:16 chs Exp $");
#undef UVM_AMAP_INLINE /* enable/disable amap inlines */ #undef UVM_AMAP_INLINE /* enable/disable amap inlines */
@ -939,15 +939,16 @@ amap_pp_adjref(amap, curslot, slotlen, adjval)
vsize_t slotlen; vsize_t slotlen;
int adjval; int adjval;
{ {
int stopslot, *ppref, lcv; int stopslot, *ppref, lcv, prevlcv;
int ref, len; int ref, len, prevref, prevlen;
stopslot = curslot + slotlen; stopslot = curslot + slotlen;
ppref = amap->am_ppref; ppref = amap->am_ppref;
prevlcv = 0;
/* /*
* first advance to the correct place in the ppref array, fragment * first advance to the correct place in the ppref array,
* if needed. * fragment if needed.
*/ */
for (lcv = 0 ; lcv < curslot ; lcv += len) { for (lcv = 0 ; lcv < curslot ; lcv += len) {
@ -957,10 +958,13 @@ amap_pp_adjref(amap, curslot, slotlen, adjval)
pp_setreflen(ppref, curslot, ref, len - (curslot -lcv)); pp_setreflen(ppref, curslot, ref, len - (curslot -lcv));
len = curslot - lcv; /* new length of entry @ lcv */ len = curslot - lcv; /* new length of entry @ lcv */
} }
prevlcv = lcv;
} }
pp_getreflen(ppref, prevlcv, &prevref, &prevlen);
/* /*
* now adjust reference counts in range (make sure we dont overshoot) * now adjust reference counts in range. merge the first
* changed entry with the last unchanged entry if possible.
*/ */
if (lcv != curslot) if (lcv != curslot)
@ -974,10 +978,14 @@ amap_pp_adjref(amap, curslot, slotlen, adjval)
len - (stopslot - lcv)); len - (stopslot - lcv));
len = stopslot - lcv; len = stopslot - lcv;
} }
ref = ref + adjval; /* ADJUST! */ ref += adjval;
if (ref < 0) if (ref < 0)
panic("amap_pp_adjref: negative reference count"); panic("amap_pp_adjref: negative reference count");
pp_setreflen(ppref, lcv, ref, len); if (lcv == prevlcv + prevlen && ref == prevref) {
pp_setreflen(ppref, prevlcv, ref, prevlen + len);
} else {
pp_setreflen(ppref, lcv, ref, len);
}
if (ref == 0) if (ref == 0)
amap_wiperange(amap, lcv, len); amap_wiperange(amap, lcv, len);
} }