minix/servers/vm/pb.c
Ben Gras 49eb1f4806 vm: new secondary cache code
Primary purpose of change: to support the mmap implementation, VM must
know both (a) about some block metadata for FS cache blocks, i.e.
inode numbers and inode offsets where applicable; and (b) know about
*all* cache blocks, i.e.  also of the FS primary caches and not just
the blocks that spill into the secondary one. This changes the
interface and VM data structures.

This change is only for the interface (libminixfs) and VM data
structures; the filesystem code is unmodified, so although the
secondary cache will be used as normal, blocks will not be annotated
with inode information until the FS is modified to provide this
information. Until it is modified, mmap of files will fail gracefully
on such filesystems.

This is indicated to VFS/VM by returning ENOSYS for REQ_PEEK.

Change-Id: I1d2df6c485e6c5e89eb28d9055076cc02629594e
2013-04-24 10:18:16 +00:00

168 lines
3.6 KiB
C

#define _SYSTEM 1
#include <minix/com.h>
#include <minix/callnr.h>
#include <minix/type.h>
#include <minix/config.h>
#include <minix/const.h>
#include <minix/sysutil.h>
#include <minix/syslib.h>
#include <minix/debug.h>
#include <minix/bitmap.h>
#include <minix/hash.h>
#include <sys/mman.h>
#include <limits.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <stdint.h>
#include <sys/param.h>
#include "vm.h"
#include "proto.h"
#include "util.h"
#include "glo.h"
#include "region.h"
#include "sanitycheck.h"
#include "memlist.h"
struct phys_block *pb_new(phys_bytes phys)
{
struct phys_block *newpb;
if(!SLABALLOC(newpb)) {
printf("vm: pb_new: couldn't allocate phys block\n");
return NULL;
}
if(phys != MAP_NONE)
assert(!(phys % VM_PAGE_SIZE));
USE(newpb,
newpb->phys = phys;
newpb->refcount = 0;
newpb->firstregion = NULL;
newpb->flags = 0;
);
return newpb;
}
void pb_free(struct phys_block *pb)
{
if(pb->phys != MAP_NONE)
free_mem(ABS2CLICK(pb->phys), 1);
SLABFREE(pb);
}
void pb_link(struct phys_region *newphysr, struct phys_block *newpb,
vir_bytes offset, struct vir_region *parent)
{
USE(newphysr,
newphysr->offset = offset;
newphysr->ph = newpb;
newphysr->parent = parent;
newphysr->next_ph_list = newpb->firstregion;
newpb->firstregion = newphysr;);
newpb->refcount++;
}
struct phys_region *pb_reference(struct phys_block *newpb,
vir_bytes offset, struct vir_region *region, mem_type_t *memtype)
{
struct phys_region *newphysr;
if(!SLABALLOC(newphysr)) {
printf("vm: pb_reference: couldn't allocate phys region\n");
return NULL;
}
newphysr->memtype = memtype;
/* New physical region. */
pb_link(newphysr, newpb, offset, region);
physblock_set(region, offset, newphysr);
return newphysr;
}
/*===========================================================================*
* pb_unreferenced *
*===========================================================================*/
void pb_unreferenced(struct vir_region *region, struct phys_region *pr, int rm)
{
struct phys_block *pb;
pb = pr->ph;
assert(pb->refcount > 0);
USE(pb, pb->refcount--;);
assert(pb->refcount >= 0);
if(pb->firstregion == pr) {
USE(pb, pb->firstregion = pr->next_ph_list;);
} else {
struct phys_region *others;
for(others = pb->firstregion; others;
others = others->next_ph_list) {
assert(others->ph == pb);
if(others->next_ph_list == pr) {
USE(others, others->next_ph_list = pr->next_ph_list;);
break;
}
}
assert(others); /* Otherwise, wasn't on the list. */
}
if(pb->refcount == 0) {
assert(!pb->firstregion);
int r;
if((r = pr->memtype->ev_unreference(pr)) != OK)
panic("unref failed, %d", r);
SLABFREE(pb);
}
pr->ph = NULL;
if(rm) physblock_set(region, pr->offset, NULL);
}
int mem_cow(struct vir_region *region,
struct phys_region *ph, phys_bytes new_page_cl, phys_bytes new_page)
{
struct phys_block *pb;
if(new_page == MAP_NONE) {
u32_t allocflags;
allocflags = vrallocflags(region->flags);
if((new_page_cl = alloc_mem(1, allocflags)) == NO_MEM)
return ENOMEM;
new_page = CLICK2ABS(new_page_cl);
}
assert(ph->ph->phys != MAP_NONE);
if(sys_abscopy(ph->ph->phys, new_page, VM_PAGE_SIZE) != OK) {
panic("VM: abscopy failed\n");
return EFAULT;
}
if(!(pb = pb_new(new_page))) {
free_mem(new_page_cl, 1);
return ENOMEM;
}
pb_unreferenced(region, ph, 0);
pb_link(ph, pb, ph->offset, region);
ph->memtype = &mem_type_anon;
return OK;
}