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Change ofw_readin/ofw_copyin to map the entire region before

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copying, rather than a page at a time. This was creating far
too many single-page mappings, and eventually OFW overflowed
some internal data structure and refused to map any more.
The new algorithm creates far less mappings and fixed a bug
where multiple mappings for the same page would be created.

'Twas known this was a problem, but only became urgent when the
install CD's mfs_root grew large enough to cause the overflow.
This commit is contained in:
Peter Grehan 2005-05-19 07:21:46 +00:00
parent 1aececdb5a
commit a9f9f6ce08
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=146368
1 changed files with 76 additions and 26 deletions
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102
sys/boot/ofw/libofw/ofw_copy.c
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@ -42,35 +42,79 @@ __FBSDID("$FreeBSD$");
#define roundup(x, y) ((((x)+((y)-1))/(y))*(y))
static int
ofw_mapmem(vm_offset_t dest, const size_t len)
{
void *destp, *addr;
size_t dlen;
size_t resid;
size_t nlen;
static vm_offset_t last_dest = 0;
static size_t last_len = 0;
nlen = len;
/*
* Check to see if this region fits in a prior mapping.
* Allocations are generally sequential, so only check
* the last one.
*/
if (dest >= last_dest &&
(dest + len) <= (last_dest + last_len)) {
return (0);
}
/*
* Trim area covered by existing mapping, if any
*/
if (dest < (last_dest + last_len)) {
nlen -= (last_dest + last_len) - dest;
dest = last_dest + last_len;
}
destp = (void *)(dest & ~PAGE_MASK);
resid = dest & PAGE_MASK;
/*
* To avoid repeated mappings on small allocations,
* never map anything less than 16 pages at a time
*/
if ((nlen + resid) < PAGE_SIZE*8) {
dlen = PAGE_SIZE*8;
} else
dlen = roundup(nlen + resid, PAGE_SIZE);
if (OF_call_method("claim", memory, 3, 1, destp, dlen, 0, &addr)
== -1) {
printf("ofw_mapmem: physical claim failed\n");
return (ENOMEM);
}
if (OF_call_method("claim", mmu, 3, 1, destp, dlen, 0, &addr) == -1) {
printf("ofw_mapmem: virtual claim failed\n");
return (ENOMEM);
}
if (OF_call_method("map", mmu, 4, 0, destp, destp, dlen, 0) == -1) {
printf("ofw_mapmem: map failed\n");
return (ENOMEM);
}
last_dest = (vm_offset_t) destp;
last_len = dlen;
return (0);
}
ssize_t
ofw_copyin(const void *src, vm_offset_t dest, const size_t len)
{
void *destp, *addr;
size_t dlen;
size_t resid;
if (ofw_mapmem(dest, len)) {
printf("ofw_copyin: map error\n");
return (0);
}
destp = (void *)(dest & ~PAGE_MASK);
resid = dest & PAGE_MASK;
dlen = roundup(len + resid, PAGE_SIZE);
if (OF_call_method("claim", memory, 3, 1, destp, dlen, 0, &addr)
== -1) {
printf("ofw_copyin: physical claim failed\n");
return (0);
}
if (OF_call_method("claim", mmu, 3, 1, destp, dlen, 0, &addr) == -1) {
printf("ofw_copyin: virtual claim failed\n");
return (0);
}
if (OF_call_method("map", mmu, 4, 0, destp, destp, dlen, 0) == -1) {
printf("ofw_copyin: map failed\n");
return (0);
}
bcopy(src, (void *)dest, len);
return(len);
bcopy(src, (void *)dest, len);
return(len);
}
ssize_t
@ -97,6 +141,12 @@ ofw_readin(const int fd, vm_offset_t dest, const size_t len)
return(0);
}
if (ofw_mapmem(dest, len)) {
printf("ofw_readin: map error\n");
free(buf);
return (0);
}
for (resid = len; resid > 0; resid -= got, p += got) {
get = min(chunk, resid);
got = read(fd, buf, get);
@ -107,7 +157,7 @@ ofw_readin(const int fd, vm_offset_t dest, const size_t len)
break;
}
ofw_copyin(buf, p, got);
bcopy(buf, (void *)p, got);
}
free(buf);