kernel: get rid of physical page bank array and use conf.mem[] instead

We can take advantage of the fact that xinit() allocates
kernel memory from conf.mem[] banks always at the beginning
of a bank, so the separate palloc.mem[] array can be eleminated
as we can calculate the amount of non-kernel memory like:

upages = cm->npage - (PGROUND(cm->klimit - cm->kbase)/BY2PG)

for the number of reserved kernel pages,
we provide the new function: ulong nkpages(Confmem*)

This eleminates the error case of running out of slots in
the array and avoids wasting memory in ports that have simple
memory configurations (compared to pc/pc64).

diff --git a/sys/src/9/pc64/mmu.c b/sys/src/9/pc64/mmu.c
index 936955d4bf293247bd5810f638e51ccc8f62fab0..23a39f6d8e317d8febbc7f84a348b2de91c4d2f3 100644 (file)
--- a/sys/src/9/pc64/mmu.c
+++ b/sys/src/9/pc64/mmu.c
@@ -652,16 +652,16 @@ patwc(void *a, int n)
 void
 preallocpages(void)
 {
-       Pallocmem *pm;
+       Confmem *cm;
        uintptr va, base, top;
        vlong tsize, psize;
        ulong np, nt;
        int i;
 
        np = 0;
-       for(i=0; i<nelem(palloc.mem); i++){
-               pm = &palloc.mem[i];
-               np += pm->npage;
+       for(i=0; i<nelem(conf.mem); i++){
+               cm = &conf.mem[i];
+               np += cm->npage - nkpages(cm);
        }
        nt = np / 50;   /* 2% for mmupool */
        np -= nt;
@@ -676,16 +676,19 @@ preallocpages(void)
        psize += tsize;
        psize = ROUND(psize, PGLSZ(1));
 
-       for(i=0; i<nelem(palloc.mem); i++){
-               pm = &palloc.mem[i];
-               base = ROUND(pm->base, PGLSZ(1));
-               top = pm->base + (uvlong)pm->npage * BY2PG;
-               if((base + psize) <= VMAPSIZE && (vlong)(top - base) >= psize){
-                       pm->base = base + psize;
-                       pm->npage = (top - pm->base)/BY2PG;
-
-                       va = base + VMAP;
-                       pmap(base | PTEGLOBAL|PTEWRITE|PTENOEXEC|PTEVALID, va, psize);
+       for(i=0; i<nelem(conf.mem); i++){
+               cm = &conf.mem[i];
+               base = cm->base;
+               top = base + (uvlong)cm->npage * BY2PG;
+               base += (uvlong)nkpages(cm) * BY2PG;
+               top &= -PGLSZ(1);
+               if(top <= VMAPSIZE && (vlong)(top - base) >= psize){
+                       /* steal memory from the end of the bank */
+                       top -= psize;
+                       cm->npage = (top - cm->base) / BY2PG;
+
+                       va = top + VMAP;
+                       pmap(top | PTEGLOBAL|PTEWRITE|PTENOEXEC|PTEVALID, va, psize);
 
                        palloc.pages = (void*)(va + tsize);
 

diff --git a/sys/src/9/port/page.c b/sys/src/9/port/page.c
index b7194058e2b8efd75754a3f2e0dc1417228b9a2b..f907aca5b7572504ee5783a31b1d050d87a9f188 100644 (file)
--- a/sys/src/9/port/page.c
+++ b/sys/src/9/port/page.c
@@ -7,21 +7,27 @@
 
 Palloc palloc;
 
+ulong
+nkpages(Confmem *cm)
+{
+       return ((cm->klimit - cm->kbase) + BY2PG-1) / BY2PG;
+}
+
 void
 pageinit(void)
 {
        int color, i, j;
        Page *p, **t;
-       Pallocmem *pm;
+       Confmem *cm;
        vlong m, v, u;
 
        if(palloc.pages == nil){
                ulong np;
 
                np = 0;
-               for(i=0; i<nelem(palloc.mem); i++){
-                       pm = &palloc.mem[i];
-                       np += pm->npage;
+               for(i=0; i<nelem(conf.mem); i++){
+                       cm = &conf.mem[i];
+                       np += cm->npage - nkpages(cm);
                }
                palloc.pages = xalloc(np*sizeof(Page));
                if(palloc.pages == nil)
@@ -35,11 +41,11 @@ pageinit(void)
        t = &palloc.head;
        p = palloc.pages;
 
-       for(i=0; i<nelem(palloc.mem); i++){
-               pm = &palloc.mem[i];
-               for(j=0; j<pm->npage; j++){
+       for(i=0; i<nelem(conf.mem); i++){
+               cm = &conf.mem[i];
+               for(j=nkpages(cm); j<cm->npage; j++){
                        memset(p, 0, sizeof *p);
-                       p->pa = pm->base+j*BY2PG;
+                       p->pa = cm->base+j*BY2PG;
                        if(cankaddr(p->pa) && (KADDR(p->pa) == nil || KADDR(p->pa) == (void*)-BY2PG))
                                continue;
                        p->color = color;

diff --git a/sys/src/9/port/portdat.h b/sys/src/9/port/portdat.h
index c1a127fb29dd0a6727ba3bc7a25bcadd03c95b0a..b3b86eaa700c66c3978ef215248274793941dd88 100644 (file)
--- a/sys/src/9/port/portdat.h
+++ b/sys/src/9/port/portdat.h
@@ -25,7 +25,6 @@ typedef struct Note   Note;
 typedef struct Page    Page;
 typedef struct Path    Path;
 typedef struct Palloc  Palloc;
-typedef struct Pallocmem       Pallocmem;
 typedef struct Perf    Perf;
 typedef struct PhysUart        PhysUart;
 typedef struct Pgrp    Pgrp;
@@ -519,12 +518,6 @@ enum
        DELTAFD = 20            /* incremental increase in Fgrp.fd's */
 };
 
-struct Pallocmem
-{
-       uintptr base;
-       ulong   npage;
-};
-
 struct Palloc
 {
        Lock;
@@ -533,7 +526,6 @@ struct Palloc
        Page    *pages;                 /* array of all pages */
        ulong   user;                   /* how many user pages */
        Rendezq         pwait[2];       /* Queues of procs waiting for memory */
-       Pallocmem       mem[16];        /* physical user page banks */
 };
 
 struct Waitq

diff --git a/sys/src/9/port/portfns.h b/sys/src/9/port/portfns.h
index 7446513be0d3dbc1ebbc8344e782ca82d5bf7b4d..d1b81a2e61c7427c8eb73b5e9cc86b10a03f07ff 100644 (file)
--- a/sys/src/9/port/portfns.h
+++ b/sys/src/9/port/portfns.h
@@ -213,6 +213,7 @@ Rgrp*               newrgrp(void);
 Proc*          newproc(void);
 void           nexterror(void);
 int            notify(Ureg*);
+ulong          nkpages(Confmem*);
 uvlong         ns2fastticks(uvlong);
 int            okaddr(uintptr, ulong, int);
 int            openmode(ulong);

diff --git a/sys/src/9/port/xalloc.c b/sys/src/9/port/xalloc.c
index 13550d4baaf6931c7e5e920b62dbe9b4e8befa8b..14998571927a274bc7c7814707f1efb61a1299fd 100644 (file)
--- a/sys/src/9/port/xalloc.c
+++ b/sys/src/9/port/xalloc.c
@@ -43,10 +43,8 @@ void
 xinit(void)
 {
        ulong maxpages, kpages, n;
-       uintptr size;
-       Confmem *m;
-       Pallocmem *pm;
        Hole *h, *eh;
+       Confmem *cm;
        int i;
 
        eh = &xlists.hole[Nhole-1];
@@ -57,36 +55,28 @@ xinit(void)
 
        kpages = conf.npage - conf.upages;
 
-       pm = palloc.mem;
        for(i=0; i<nelem(conf.mem); i++){
-               m = &conf.mem[i];
-               n = m->npage;
+               cm = &conf.mem[i];
+               n = cm->npage;
                if(n > kpages)
                        n = kpages;
                /* don't try to use non-KADDR-able memory for kernel */
-               maxpages = cankaddr(m->base)/BY2PG;
+               maxpages = cankaddr(cm->base)/BY2PG;
                if(n > maxpages)
                        n = maxpages;
-               size = (uintptr)n*BY2PG;
-               /* first give to kernel */
+               /* give to kernel */
                if(n > 0){
-                       m->kbase = (uintptr)KADDR(m->base);
-                       m->klimit = (uintptr)m->kbase+size;
-                       if(m->klimit == 0)
-                               m->klimit = (uintptr)-BY2PG;
-                       xhole(m->base, m->klimit - m->kbase);
+                       cm->kbase = (uintptr)KADDR(cm->base);
+                       cm->klimit = (uintptr)cm->kbase+(uintptr)n*BY2PG;
+                       if(cm->klimit == 0)
+                               cm->klimit = (uintptr)-BY2PG;
+                       xhole(cm->base, cm->klimit - cm->kbase);
                        kpages -= n;
                }
-               /* if anything left over, give to user */
-               if(n < m->npage){
-                       if(pm >= palloc.mem+nelem(palloc.mem)){
-                               print("xinit: losing %lud pages\n", m->npage-n);
-                               continue;
-                       }
-                       pm->base = m->base+size;
-                       pm->npage = m->npage - n;
-                       pm++;
-               }
+               /*
+                * anything left over: cm->npage - nkpages(cm)
+                * will be given to user by pageinit()
+                */
        }
        xsummary();
 }