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cache_prefetch() now comes in two flavours: one with a direct vnode pointer, 

the other one with usual device/inode ID pair.
Both versions now accept an offset/size pair to specify the region of the
file to be prefetched - this may be turned into a file_vec_io array later on.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@13866 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler 2005-08-01 14:24:58 +00:00
parent b7d8ef5a0d
commit 186857529e
2 changed files with 26 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
headers/private/kernel/file_cache.h
View File

@ -42,7 +42,8 @@ extern void cache_node_opened(void *vnode, int32 fdType, vm_cache_ref *cache,
extern void cache_node_closed(void *vnode, int32 fdType, vm_cache_ref *cache,
mount_id mountID, vnode_id vnodeID);
extern void cache_node_launched(size_t argCount, char * const *args);
extern void cache_prefetch(mount_id mountID, vnode_id vnodeID);
extern void cache_prefetch_vnode(void *vnode, off_t offset, size_t size);
extern void cache_prefetch(mount_id mountID, vnode_id vnodeID, off_t offset, size_t size);
extern status_t file_cache_init(void);
extern vm_store *vm_create_vnode_store(void *vnode);

40
src/system/kernel/cache/file_cache.cpp vendored
View File

@ -611,21 +611,9 @@ file_cache_control(const char *subsystem, uint32 function, void *buffer, size_t
extern "C" void
cache_prefetch(mount_id mountID, vnode_id vnodeID)
cache_prefetch_vnode(void *vnode, off_t offset, size_t size)
{
vm_cache_ref *cache;
void *vnode;
// ToDo: schedule prefetch
// ToDo: maybe get 1) access type (random/sequential), 2) file vecs which blocks to prefetch
// for now, we just prefetch the first 64 kB
TRACE(("cache_prefetch(vnode %ld:%Ld)\n", mountID, vnodeID));
// get the vnode for the object, this also grabs a ref to it
if (vfs_get_vnode(mountID, vnodeID, &vnode) != B_OK)
return;
if (vfs_get_vnode_cache(vnode, &cache) != B_OK) {
vfs_vnode_release_ref(vnode);
return;
@ -634,17 +622,20 @@ cache_prefetch(mount_id mountID, vnode_id vnodeID)
file_cache_ref *ref = (struct file_cache_ref *)((vnode_store *)cache->cache->store)->file_cache_ref;
off_t fileSize = cache->cache->virtual_size;
size_t size = 65536;
if (size > fileSize)
size = fileSize;
// we never fetch more than 4 MB at once
if (size > 4 * 1024 * 1024)
size = 4 * 1024 * 1024;
size_t bytesLeft = size, lastLeft = size;
off_t lastOffset = 0;
off_t lastOffset = offset;
size_t lastSize = 0;
mutex_lock(&cache->lock);
for (off_t offset = 0; bytesLeft > 0; offset += B_PAGE_SIZE) {
for (; bytesLeft > 0; offset += B_PAGE_SIZE) {
// check if this page is already in memory
addr_t virtualAddress;
restart:
@ -677,6 +668,23 @@ cache_prefetch(mount_id mountID, vnode_id vnodeID)
out:
mutex_unlock(&cache->lock);
}
extern "C" void
cache_prefetch(mount_id mountID, vnode_id vnodeID, off_t offset, size_t size)
{
void *vnode;
// ToDo: schedule prefetch
TRACE(("cache_prefetch(vnode %ld:%Ld)\n", mountID, vnodeID));
// get the vnode for the object, this also grabs a ref to it
if (vfs_get_vnode(mountID, vnodeID, &vnode) != B_OK)
return;
cache_prefetch_vnode(vnode, offset, size);
vfs_vnode_release_ref(vnode);
}