int cache_freepages(int pages)
{
struct cached_page *cp, *newercp;
int freed = 0;
int oldsteps = 0;
int skips = 0;
for(cp = lru_oldest; cp && freed < pages; cp = newercp) {
newercp = cp->newer;
assert(cp->page->refcount >= 1);
if(cp->page->refcount == 1) {
rmcache(cp);
freed++;
skips = 0;
} else skips++;
oldsteps++;
}
return freed;
}
int
do_setcache(message *msg)
{
int r;
dev_t dev = msg->m_u.m_vmmcp.dev;
u64_t dev_off = (u64_t) msg->m_u.m_vmmcp.dev_offset_pages * VM_PAGE_SIZE;
u64_t ino_off = (u64_t) msg->m_u.m_vmmcp.ino_offset_pages * VM_PAGE_SIZE;
int n;
struct vmproc *caller;
vir_bytes offset;
int bytes = msg->m_u.m_vmmcp.pages * VM_PAGE_SIZE;
if(bytes < VM_PAGE_SIZE) return EINVAL;
if(vm_isokendpt(msg->m_source, &n) != OK) panic("bogus source");
caller = &vmproc[n];
for(offset = 0; offset < bytes; offset += VM_PAGE_SIZE) {
struct vir_region *region;
struct phys_region *phys_region = NULL;
vir_bytes v = (vir_bytes) msg->m_u.m_vmmcp.block + offset;
struct cached_page *hb;
if(!(region = map_lookup(caller, v, &phys_region))) {
printf("VM: error: no reasonable memory region given (offset 0x%lx, 0x%lx)\n", offset, v);
return EFAULT;
}
if(!phys_region) {
printf("VM: error: no available memory region given\n");
return EFAULT;
}
if((hb=find_cached_page_bydev(dev, dev_off + offset,
msg->m_u.m_vmmcp.ino, ino_off + offset, 1))) {
/* block inode info updated */
if(hb->page != phys_region->ph) {
/* previous cache entry has become
* obsolete; make a new one. rmcache
* removes it from the cache and frees
* the page if it isn't mapped in anywhere
* else.
*/
rmcache(hb);
} else {
/* block was already there, inode info might've changed which is fine */
continue;
}
}
if(phys_region->memtype != &mem_type_anon &&
phys_region->memtype != &mem_type_anon_contig) {
printf("VM: error: no reasonable memory type\n");
return EFAULT;
}
if(phys_region->ph->refcount != 1) {
printf("VM: error: no reasonable refcount\n");
return EFAULT;
}
phys_region->memtype = &mem_type_cache;
if((r=addcache(dev, dev_off + offset,
msg->m_u.m_vmmcp.ino, ino_off + offset, phys_region->ph)) != OK) {
printf("VM: addcache failed\n");
return r;
}
}
#if CACHE_SANITY
cache_sanitycheck_internal();
#endif
return OK;
}
static int mappedfile_pagefault(struct vmproc *vmp, struct vir_region *region,
struct phys_region *ph, int write, vfs_callback_t cb,
void *state, int statelen, int *io)
{
u32_t allocflags;
int procfd = region->param.file.fdref->fd;
allocflags = vrallocflags(region->flags);
assert(ph->ph->refcount > 0);
assert(region->param.file.inited);
assert(region->param.file.fdref);
assert(region->param.file.fdref->dev != NO_DEV);
/* Totally new block? Create it. */
if(ph->ph->phys == MAP_NONE) {
struct cached_page *cp;
u64_t referenced_offset =
region->param.file.offset + ph->offset;
if(region->param.file.fdref->ino == VMC_NO_INODE) {
cp = find_cached_page_bydev(region->param.file.fdref->dev,
referenced_offset, VMC_NO_INODE, 0, 1);
} else {
cp = find_cached_page_byino(region->param.file.fdref->dev,
region->param.file.fdref->ino, referenced_offset, 1);
}
/*
* Normally, a cache hit saves a round-trip to the file system
* to load the page. However, if the page in the VM cache is
* marked for one-time use, then force a round-trip through the
* file system anyway, so that the FS can update the page by
* by readding it to the cache. Thus, for one-time use pages,
* no caching is performed. This approach is correct even in
* the light of concurrent requests and disappearing processes
* but relies on VM requests to VFS being fully serialized.
*/
if(cp && (!cb || !(cp->flags & VMSF_ONCE))) {
int result = OK;
pb_unreferenced(region, ph, 0);
pb_link(ph, cp->page, ph->offset, region);
if(roundup(ph->offset+region->param.file.clearend,
VM_PAGE_SIZE) >= region->length) {
result = cow_block(vmp, region, ph,
region->param.file.clearend);
} else if(result == OK && write) {
result = cow_block(vmp, region, ph, 0);
}
/* Discard one-use pages after mapping them in. */
if (result == OK && (cp->flags & VMSF_ONCE))
rmcache(cp);
return result;
}
if(!cb) {
#if 0
printf("VM: mem_file: no callback, returning EFAULT\n");
sys_diagctl_stacktrace(vmp->vm_endpoint);
#endif
return EFAULT;
}
if(vfs_request(VMVFSREQ_FDIO, procfd, vmp, referenced_offset,
VM_PAGE_SIZE, cb, NULL, state, statelen) != OK) {
printf("VM: mappedfile_pagefault: vfs_request failed\n");
return ENOMEM;
}
*io = 1;
return SUSPEND;
}
if(!write) {
#if 0
printf("mappedfile_pagefault: nonwrite fault?\n");
#endif
return OK;
}
return cow_block(vmp, region, ph, 0);
}
