240 lines
6.1 KiB
C
240 lines
6.1 KiB
C
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/* This file implements the disk cache.
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*
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* If they exist anywhere, cached pages are always in a private
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* VM datastructure.
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*
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* They might also be any combination of:
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* - be mapped in by a filesystem for reading/writing by it
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* - be mapped in by a process as the result of an mmap call (future)
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*
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* This file manages the datastructure of all cache blocks, and
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* mapping them in and out of filesystems.
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*/
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#include <assert.h>
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#include <string.h>
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#include <minix/hash.h>
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#include "proto.h"
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#include "vm.h"
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#include "region.h"
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#include "glo.h"
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#include "cache.h"
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static int cache_reference(struct phys_region *pr, struct phys_region *pr2);
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static int cache_unreference(struct phys_region *pr);
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static int cache_sanitycheck(struct phys_region *pr, char *file, int line);
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static int cache_writable(struct phys_region *pr);
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static int cache_resize(struct vmproc *vmp, struct vir_region *vr, vir_bytes l);
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static int cache_pagefault(struct vmproc *vmp, struct vir_region *region,
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struct phys_region *ph, int write, vfs_callback_t cb, void *state,
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int len, int *io);
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static int cache_pt_flags(struct vir_region *vr);
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struct mem_type mem_type_cache = {
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.name = "cache memory",
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.ev_reference = cache_reference,
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.ev_unreference = cache_unreference,
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.ev_resize = cache_resize,
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.ev_sanitycheck = cache_sanitycheck,
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.ev_pagefault = cache_pagefault,
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.writable = cache_writable,
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.pt_flags = cache_pt_flags,
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};
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static int cache_pt_flags(struct vir_region *vr){
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#if defined(__arm__)
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return ARM_VM_PTE_CACHED;
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#else
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return 0;
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#endif
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}
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static int cache_reference(struct phys_region *pr, struct phys_region *pr2)
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{
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return OK;
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}
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static int cache_unreference(struct phys_region *pr)
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{
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return mem_type_anon.ev_unreference(pr);
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}
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static int cache_sanitycheck(struct phys_region *pr, char *file, int line)
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{
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MYASSERT(usedpages_add(pr->ph->phys, VM_PAGE_SIZE) == OK);
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return OK;
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}
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static int cache_writable(struct phys_region *pr)
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{
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/* Cache blocks are at the moment only used by filesystems so always writable. */
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assert(pr->ph->refcount > 0);
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return pr->ph->phys != MAP_NONE;
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}
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static int cache_resize(struct vmproc *vmp, struct vir_region *vr, vir_bytes l)
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{
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printf("VM: cannot resize cache blocks.\n");
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return ENOMEM;
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}
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int
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do_mapcache(message *msg)
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{
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dev_t dev = msg->m_u.m_vmmcp.dev;
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u64_t dev_off = (u64_t) msg->m_u.m_vmmcp.dev_offset_pages * VM_PAGE_SIZE;
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u64_t ino_off = (u64_t) msg->m_u.m_vmmcp.ino_offset_pages * VM_PAGE_SIZE;
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int n;
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phys_bytes bytes = msg->m_u.m_vmmcp.pages * VM_PAGE_SIZE;
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struct vir_region *vr;
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struct vmproc *caller;
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vir_bytes offset;
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int io = 0;
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if(vm_isokendpt(msg->m_source, &n) != OK) panic("bogus source");
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caller = &vmproc[n];
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if(bytes < VM_PAGE_SIZE) return EINVAL;
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if(!(vr = map_page_region(caller, VM_PAGE_SIZE, VM_DATATOP, bytes,
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VR_ANON | VR_WRITABLE, 0, &mem_type_cache))) {
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printf("VM: map_page_region failed\n");
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return ENOMEM;
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}
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assert(vr->length == bytes);
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for(offset = 0; offset < bytes; offset += VM_PAGE_SIZE) {
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struct cached_page *hb;
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assert(vr->length == bytes);
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assert(offset < vr->length);
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if(!(hb = find_cached_page_bydev(dev, dev_off + offset,
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msg->m_u.m_vmmcp.ino, ino_off + offset, 1))) {
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map_unmap_region(caller, vr, 0, bytes);
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return ENOENT;
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}
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assert(!vr->param.pb_cache);
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vr->param.pb_cache = hb->page;
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assert(vr->length == bytes);
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assert(offset < vr->length);
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if(map_pf(caller, vr, offset, 1, NULL, NULL, 0, &io) != OK) {
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map_unmap_region(caller, vr, 0, bytes);
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printf("VM: map_pf failed\n");
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return ENOMEM;
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}
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assert(!vr->param.pb_cache);
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}
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memset(msg, 0, sizeof(*msg));
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msg->m_u.m_vmmcp_reply.addr = (void *) vr->vaddr;
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assert(vr);
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#if CACHE_SANITY
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cache_sanitycheck_internal();
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#endif
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return OK;
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}
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static int cache_pagefault(struct vmproc *vmp, struct vir_region *region,
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struct phys_region *ph, int write, vfs_callback_t cb,
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void *state, int len, int *io)
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{
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vir_bytes offset = ph->offset;
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assert(ph->ph->phys == MAP_NONE);
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assert(region->param.pb_cache);
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pb_unreferenced(region, ph, 0);
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pb_link(ph, region->param.pb_cache, offset, region);
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region->param.pb_cache = NULL;
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return OK;
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}
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int
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do_setcache(message *msg)
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{
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int r;
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dev_t dev = msg->m_u.m_vmmcp.dev;
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u64_t dev_off = (u64_t) msg->m_u.m_vmmcp.dev_offset_pages * VM_PAGE_SIZE;
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u64_t ino_off = (u64_t) msg->m_u.m_vmmcp.ino_offset_pages * VM_PAGE_SIZE;
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int n;
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struct vmproc *caller;
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phys_bytes offset;
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phys_bytes bytes = msg->m_u.m_vmmcp.pages * VM_PAGE_SIZE;
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if(bytes < VM_PAGE_SIZE) return EINVAL;
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if(vm_isokendpt(msg->m_source, &n) != OK) panic("bogus source");
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caller = &vmproc[n];
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for(offset = 0; offset < bytes; offset += VM_PAGE_SIZE) {
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struct vir_region *region;
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struct phys_region *phys_region = NULL;
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vir_bytes v = (vir_bytes) msg->m_u.m_vmmcp.block + offset;
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struct cached_page *hb;
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if(!(region = map_lookup(caller, v, &phys_region))) {
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printf("VM: error: no reasonable memory region given (offset 0x%lx, 0x%lx)\n", offset, v);
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return EFAULT;
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}
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if(!phys_region) {
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printf("VM: error: no available memory region given\n");
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return EFAULT;
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}
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if((hb=find_cached_page_bydev(dev, dev_off + offset,
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msg->m_u.m_vmmcp.ino, ino_off + offset, 1))) {
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/* block inode info updated */
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if(hb->page != phys_region->ph) {
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/* previous cache entry has become
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* obsolete; make a new one. rmcache
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* removes it from the cache and frees
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* the page if it isn't mapped in anywhere
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* else.
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*/
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rmcache(hb);
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} else {
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/* block was already there, inode info might've changed which is fine */
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continue;
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}
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}
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if(phys_region->memtype != &mem_type_anon &&
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phys_region->memtype != &mem_type_anon_contig) {
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printf("VM: error: no reasonable memory type\n");
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return EFAULT;
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}
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if(phys_region->ph->refcount != 1) {
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printf("VM: error: no reasonable refcount\n");
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return EFAULT;
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}
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phys_region->memtype = &mem_type_cache;
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if((r=addcache(dev, dev_off + offset,
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msg->m_u.m_vmmcp.ino, ino_off + offset, phys_region->ph)) != OK) {
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printf("VM: addcache failed\n");
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return r;
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}
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}
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#if CACHE_SANITY
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cache_sanitycheck_internal();
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#endif
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return OK;
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}
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