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Flushing pages to vfs will work, but the issue is that while vfs is

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serving mm0, if it page faults, system deadlocks because mm0 is waiting to be served by vfs.

FIX: To fix this, mm0 will need to fork itself and keep a separate thread solely for
page fault handling.
This commit is contained in:
Bahadir Balban
2008-05-28 23:37:41 +03:00
parent 98888a94b5
commit f561d885d5
6 changed files with 39 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
tasks/fs0/src/syscalls.c
View File

@@ -30,6 +30,8 @@ int pager_sys_open(l4id_t sender, int fd, unsigned long vnum, unsigned long size
{
int err;
printf("%s/%s\n", __TASKNAME__, __FUNCTION__);
l4_save_ipcregs();
write_mr(L4SYS_ARG0, sender);
@@ -104,6 +106,8 @@ int pager_sys_close(l4id_t sender, l4id_t closer, int fd)
struct tcb *task;
int err;
printf("%s/%s\n", __TASKNAME__, __FUNCTION__);
BUG_ON(!(task = find_task(closer)));
printf("Deleting fd: %d\n", fd);
@@ -132,6 +136,7 @@ int sys_open(l4id_t sender, const char *pathname, int flags, unsigned int mode)
int fd;
int retval, err;
printf("%s/%s\n", __TASKNAME__, __FUNCTION__);
/* Get the task */
BUG_ON(!(task = find_task(sender)));
@@ -337,6 +342,7 @@ int pager_sys_read(l4id_t sender, unsigned long vnum, unsigned long f_offset,
struct vnode *v;
int err, retval = 0;
printf("%s/%s\n", __TASKNAME__, __FUNCTION__);
if (sender != PAGER_TID) {
retval = -EINVAL;
goto out;
@@ -370,6 +376,7 @@ int pager_update_stats(l4id_t sender, unsigned long vnum,
struct vnode *v;
int retval = 0;
printf("%s/%s\n", __TASKNAME__, __FUNCTION__);
if (sender != PAGER_TID) {
retval = -EINVAL;
goto out;
@@ -402,6 +409,7 @@ int pager_sys_write(l4id_t sender, unsigned long vnum, unsigned long f_offset,
struct vnode *v;
int err, retval = 0;
printf("%s/%s\n", __TASKNAME__, __FUNCTION__);
if (sender != PAGER_TID) {
retval = -EINVAL;
goto out;
@@ -419,6 +427,9 @@ int pager_sys_write(l4id_t sender, unsigned long vnum, unsigned long f_offset,
goto out;
}
printf("%s/%s: Writing to vnode %lu, at pgoff 0x%x, %d pages, buf at 0x%x\n",
__TASKNAME__, __FUNCTION__, vnum, f_offset, npages, pagebuf);
/*
* If the file is extended, write silently extends it.
* But we expect an explicit pager_update_stats from the
@@ -430,7 +441,9 @@ int pager_sys_write(l4id_t sender, unsigned long vnum, unsigned long f_offset,
}
out:
printf("%s/%s: Returning ipc result.\n", __TASKNAME__, __FUNCTION__);
l4_ipc_return(retval);
printf("%s/%s: Done.\n", __TASKNAME__, __FUNCTION__);
return 0;
}
@@ -482,6 +495,7 @@ int sys_readdir(l4id_t sender, int fd, void *buf, int count)
struct dentry *d;
struct tcb *t;
printf("%s/%s\n", __TASKNAME__, __FUNCTION__);
/* Get the task */
BUG_ON(!(t = find_task(sender)));

12
tasks/mm0/src/file.c
View File

@@ -55,6 +55,8 @@ int vfs_read(unsigned long vnum, unsigned long file_offset,
{
int err;
printf("%s/%s\n", __TASKNAME__, __FUNCTION__);
l4_save_ipcregs();
write_mr(L4SYS_ARG0, vnum);
@@ -90,6 +92,8 @@ int vfs_receive_sys_open(l4id_t sender, l4id_t opener, int fd,
struct vm_file *vmfile;
struct tcb *t;
printf("%s/%s\n", __TASKNAME__, __FUNCTION__);
/* Check argument validity */
if (sender != VFS_TID) {
l4_ipc_return(-EPERM);
@@ -214,6 +218,7 @@ int vfs_write(unsigned long vnum, unsigned long file_offset,
{
int err;
printf("%s/%s\n", __TASKNAME__, __FUNCTION__);
l4_save_ipcregs();
write_mr(L4SYS_ARG0, vnum);
@@ -241,6 +246,7 @@ int vfs_close(l4id_t sender, int fd)
{
int err;
printf("%s/%s Sending to %d\n", __TASKNAME__, __FUNCTION__, VFS_TID);
l4_save_ipcregs();
write_mr(L4SYS_ARG0, sender);
@@ -250,6 +256,7 @@ int vfs_close(l4id_t sender, int fd)
printf("%s: L4 IPC Error: %d.\n", __FUNCTION__, err);
return err;
}
printf("%s/%s Received from %d\n", __TASKNAME__, __FUNCTION__, VFS_TID);
/* Check if syscall was successful */
if ((err = l4_get_retval()) < 0) {
@@ -267,6 +274,7 @@ int vfs_update_file_stats(struct vm_file *f)
{
int err;
printf("%s/%s\n", __TASKNAME__, __FUNCTION__);
l4_save_ipcregs();
write_mr(L4SYS_ARG0, vm_file_to_vnum(f));
@@ -373,7 +381,7 @@ int sys_close(l4id_t sender, int fd)
l4_ipc_return(retval);
return 0;
}
/* Close the file descriptor. */
retval = fd_close(sender, fd);
printf("%s: Closed fd %d. Returning %d\n",
@@ -454,6 +462,7 @@ copy:
copy_offset = (unsigned long)buf;
page_copy(head, task_virt_to_page(task, copy_offset),
cursor_offset, copy_offset & PAGE_MASK, copysize);
head->flags |= VM_DIRTY;
left -= copysize;
last_pgoff = head->offset;
@@ -473,6 +482,7 @@ copy:
page_copy(this, task_virt_to_page(task, copy_offset),
0, 0, copysize);
this->flags |= VM_DIRTY;
left -= copysize;
last_pgoff = this->offset;
}

6
tasks/mm0/src/pagers.c
View File

@@ -84,9 +84,15 @@ int file_page_out(struct vm_object *vm_obj, unsigned long page_offset)
if (!(page->flags & VM_DIRTY))
return 0;
paddr = (void *)page_to_phys(page);
vaddr = phys_to_virt(paddr);
/* Map the page to vfs task */
l4_map(paddr, vaddr, 1, MAP_USR_RW_FLAGS, VFS_TID);
printf("%s/%s: Writing to vnode %d, at pgoff 0x%x, %d pages, buf at 0x%x\n",
__TASKNAME__, __FUNCTION__, vm_file_to_vnum(f), page_offset, 1, vaddr);
/* Syscall to vfs to write page back to file. */
if ((err = vfs_write(vm_file_to_vnum(f), page_offset, 1, vaddr)) < 0)
goto out_err;

2
tasks/test0/src/fileio.c
View File

@@ -21,7 +21,7 @@ int fileio2(void)
perror("OPEN");
return -1;
}
printf("Created newfile.txt\n");
printf("Created newfile2.txt\n");
printf("%s: write.\n", __TASKNAME__);
if ((int)(cnt = write(fd, str, strlen(str))) < 0) {