Various cleanups to the main function for AIO kernel processes:
- Pull the vmspace logic out into helper functions and reduce duplication. Operations on the vmspace are all isolated to vm_map.c, but it now exports a new 'vmspace_switch_aio' for use by AIO kernel processes. - When an AIO kernel process wants to exit, break out of the main loop and perform cleanup after the loop end. This reduces a lot of indentation and allows cleanup to more closely mirror setup actions before the loop starts. - Convert a DIAGNOSTIC to KASSERT(). - Replace mycp with more typical 'p'. Reviewed by: kib Sponsored by: Chelsio Communications Differential Revision: https://reviews.freebsd.org/D4990
This commit is contained in:
John Baldwin
parent
f2e7f06a0d
commit
8a4dc40ff4
@ -1048,6 +1048,13 @@ notification_done:
|
||||
}
|
||||
}
|
||||
|
||||
static void
|
||||
aio_switch_vmspace(struct aiocblist *aiocbe)
|
||||
{
|
||||
|
||||
vmspace_switch_aio(aiocbe->userproc->p_vmspace);
|
||||
}
|
||||
|
||||
/*
|
||||
* The AIO daemon, most of the actual work is done in aio_process_*,
|
||||
* but the setup (and address space mgmt) is done in this routine.
|
||||
@ -1058,18 +1065,20 @@ aio_daemon(void *_id)
|
||||
struct aiocblist *aiocbe;
|
||||
struct aiothreadlist *aiop;
|
||||
struct kaioinfo *ki;
|
||||
struct proc *curcp, *mycp, *userp;
|
||||
struct vmspace *myvm, *tmpvm;
|
||||
struct proc *p, *userp;
|
||||
struct vmspace *myvm;
|
||||
struct thread *td = curthread;
|
||||
int id = (intptr_t)_id;
|
||||
|
||||
/*
|
||||
* Local copies of curproc (cp) and vmspace (myvm)
|
||||
* Grab an extra reference on the daemon's vmspace so that it
|
||||
* doesn't get freed by jobs that switch to a different
|
||||
* vmspace.
|
||||
*/
|
||||
mycp = td->td_proc;
|
||||
myvm = mycp->p_vmspace;
|
||||
p = td->td_proc;
|
||||
myvm = vmspace_acquire_ref(p);
|
||||
|
||||
KASSERT(mycp->p_textvp == NULL, ("kthread has a textvp"));
|
||||
KASSERT(p->p_textvp == NULL, ("kthread has a textvp"));
|
||||
|
||||
/*
|
||||
* Allocate and ready the aio control info. There is one aiop structure
|
||||
@ -1087,12 +1096,6 @@ aio_daemon(void *_id)
|
||||
|
||||
mtx_lock(&aio_job_mtx);
|
||||
for (;;) {
|
||||
/*
|
||||
* curcp is the current daemon process context.
|
||||
* userp is the current user process context.
|
||||
*/
|
||||
curcp = mycp;
|
||||
|
||||
/*
|
||||
* Take daemon off of free queue
|
||||
*/
|
||||
@ -1111,34 +1114,7 @@ aio_daemon(void *_id)
|
||||
/*
|
||||
* Connect to process address space for user program.
|
||||
*/
|
||||
if (userp != curcp) {
|
||||
/*
|
||||
* Save the current address space that we are
|
||||
* connected to.
|
||||
*/
|
||||
tmpvm = mycp->p_vmspace;
|
||||
|
||||
/*
|
||||
* Point to the new user address space, and
|
||||
* refer to it.
|
||||
*/
|
||||
mycp->p_vmspace = userp->p_vmspace;
|
||||
atomic_add_int(&mycp->p_vmspace->vm_refcnt, 1);
|
||||
|
||||
/* Activate the new mapping. */
|
||||
pmap_activate(FIRST_THREAD_IN_PROC(mycp));
|
||||
|
||||
/*
|
||||
* If the old address space wasn't the daemons
|
||||
* own address space, then we need to remove the
|
||||
* daemon's reference from the other process
|
||||
* that it was acting on behalf of.
|
||||
*/
|
||||
if (tmpvm != myvm) {
|
||||
vmspace_free(tmpvm);
|
||||
}
|
||||
curcp = userp;
|
||||
}
|
||||
aio_switch_vmspace(aiocbe);
|
||||
|
||||
ki = userp->p_aioinfo;
|
||||
|
||||
@ -1172,34 +1148,13 @@ aio_daemon(void *_id)
|
||||
/*
|
||||
* Disconnect from user address space.
|
||||
*/
|
||||
if (curcp != mycp) {
|
||||
|
||||
if (p->p_vmspace != myvm) {
|
||||
mtx_unlock(&aio_job_mtx);
|
||||
|
||||
/* Get the user address space to disconnect from. */
|
||||
tmpvm = mycp->p_vmspace;
|
||||
|
||||
/* Get original address space for daemon. */
|
||||
mycp->p_vmspace = myvm;
|
||||
|
||||
/* Activate the daemon's address space. */
|
||||
pmap_activate(FIRST_THREAD_IN_PROC(mycp));
|
||||
#ifdef DIAGNOSTIC
|
||||
if (tmpvm == myvm) {
|
||||
printf("AIOD: vmspace problem -- %d\n",
|
||||
mycp->p_pid);
|
||||
}
|
||||
#endif
|
||||
/* Remove our vmspace reference. */
|
||||
vmspace_free(tmpvm);
|
||||
|
||||
curcp = mycp;
|
||||
|
||||
vmspace_switch_aio(myvm);
|
||||
mtx_lock(&aio_job_mtx);
|
||||
/*
|
||||
* We have to restart to avoid race, we only sleep if
|
||||
* no job can be selected, that should be
|
||||
* curcp == mycp.
|
||||
* no job can be selected.
|
||||
*/
|
||||
continue;
|
||||
}
|
||||
@ -1214,29 +1169,23 @@ aio_daemon(void *_id)
|
||||
* thereby freeing resources.
|
||||
*/
|
||||
if (msleep(aiop->aiothread, &aio_job_mtx, PRIBIO, "aiordy",
|
||||
aiod_lifetime)) {
|
||||
if (TAILQ_EMPTY(&aio_jobs)) {
|
||||
if ((aiop->aiothreadflags & AIOP_FREE) &&
|
||||
(num_aio_procs > target_aio_procs)) {
|
||||
TAILQ_REMOVE(&aio_freeproc, aiop, list);
|
||||
num_aio_procs--;
|
||||
mtx_unlock(&aio_job_mtx);
|
||||
uma_zfree(aiop_zone, aiop);
|
||||
free_unr(aiod_unr, id);
|
||||
#ifdef DIAGNOSTIC
|
||||
if (mycp->p_vmspace->vm_refcnt <= 1) {
|
||||
printf("AIOD: bad vm refcnt for"
|
||||
" exiting daemon: %d\n",
|
||||
mycp->p_vmspace->vm_refcnt);
|
||||
}
|
||||
#endif
|
||||
kproc_exit(0);
|
||||
}
|
||||
}
|
||||
}
|
||||
aiod_lifetime) == EWOULDBLOCK && TAILQ_EMPTY(&aio_jobs) &&
|
||||
(aiop->aiothreadflags & AIOP_FREE) &&
|
||||
num_aio_procs > target_aio_procs)
|
||||
break;
|
||||
}
|
||||
TAILQ_REMOVE(&aio_freeproc, aiop, list);
|
||||
num_aio_procs--;
|
||||
mtx_unlock(&aio_job_mtx);
|
||||
panic("shouldn't be here\n");
|
||||
uma_zfree(aiop_zone, aiop);
|
||||
free_unr(aiod_unr, id);
|
||||
vmspace_free(myvm);
|
||||
|
||||
KASSERT(p->p_vmspace == myvm,
|
||||
("AIOD: bad vmspace for exiting daemon"));
|
||||
KASSERT(myvm->vm_refcnt > 1,
|
||||
("AIOD: bad vm refcnt for exiting daemon: %d", myvm->vm_refcnt));
|
||||
kproc_exit(0);
|
||||
}
|
||||
|
||||
/*
|
||||
|
||||
@ -106,6 +106,7 @@ void vmspace_exit(struct thread *);
|
||||
struct vmspace *vmspace_acquire_ref(struct proc *);
|
||||
void vmspace_free(struct vmspace *);
|
||||
void vmspace_exitfree(struct proc *);
|
||||
void vmspace_switch_aio(struct vmspace *);
|
||||
void vnode_pager_setsize(struct vnode *, vm_ooffset_t);
|
||||
int vslock(void *, size_t);
|
||||
void vsunlock(void *, size_t);
|
||||
|
||||
@ -451,6 +451,51 @@ vmspace_acquire_ref(struct proc *p)
|
||||
return (vm);
|
||||
}
|
||||
|
||||
/*
|
||||
* Switch between vmspaces in an AIO kernel process.
|
||||
*
|
||||
* The AIO kernel processes switch to and from a user process's
|
||||
* vmspace while performing an I/O operation on behalf of a user
|
||||
* process. The new vmspace is either the vmspace of a user process
|
||||
* obtained from an active AIO request or the initial vmspace of the
|
||||
* AIO kernel process (when it is idling). Because user processes
|
||||
* will block to drain any active AIO requests before proceeding in
|
||||
* exit() or execve(), the vmspace reference count for these vmspaces
|
||||
* can never be 0. This allows for a much simpler implementation than
|
||||
* the loop in vmspace_acquire_ref() above. Similarly, AIO kernel
|
||||
* processes hold an extra reference on their initial vmspace for the
|
||||
* life of the process so that this guarantee is true for any vmspace
|
||||
* passed as 'newvm'.
|
||||
*/
|
||||
void
|
||||
vmspace_switch_aio(struct vmspace *newvm)
|
||||
{
|
||||
struct vmspace *oldvm;
|
||||
|
||||
/* XXX: Need some way to assert that this is an aio daemon. */
|
||||
|
||||
KASSERT(newvm->vm_refcnt > 0,
|
||||
("vmspace_switch_aio: newvm unreferenced"));
|
||||
|
||||
oldvm = curproc->p_vmspace;
|
||||
if (oldvm == newvm)
|
||||
return;
|
||||
|
||||
/*
|
||||
* Point to the new address space and refer to it.
|
||||
*/
|
||||
curproc->p_vmspace = newvm;
|
||||
atomic_add_int(&newvm->vm_refcnt, 1);
|
||||
|
||||
/* Activate the new mapping. */
|
||||
pmap_activate(curthread);
|
||||
|
||||
/* Remove the daemon's reference to the old address space. */
|
||||
KASSERT(oldvm->vm_refcnt > 1,
|
||||
("vmspace_switch_aio: oldvm dropping last reference"));
|
||||
vmspace_free(oldvm);
|
||||
}
|
||||
|
||||
void
|
||||
_vm_map_lock(vm_map_t map, const char *file, int line)
|
||||
{
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user