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proc: Remove kernel stack swapping support, part 7

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Remove some uses of PHOLD which were there only to prevent the process'
threads from being swapped out.

Tested by:	pho
Reviewed by:	imp, kib
Differential Revision:	https://reviews.freebsd.org/D46118
This commit is contained in:
Mark Johnston 2024-07-29 01:41:06 +00:00
parent 472888018c
commit d37286b9bf
8 changed files with 0 additions and 61 deletions
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14
sys/cam/cam_periph.c
View file

@ -928,16 +928,6 @@ cam_periph_mapmem(union ccb *ccb, struct cam_periph_map_info *mapinfo,
}
}
/*
* This keeps the kernel stack of current thread from getting
* swapped. In low-memory situations where the kernel stack might
* otherwise get swapped out, this holds it and allows the thread
* to make progress and release the kernel mapped pages sooner.
*
* XXX KDM should I use P_NOSWAP instead?
*/
PHOLD(curproc);
for (i = 0; i < numbufs; i++) {
/* Save the user's data address. */
mapinfo->orig[i] = *data_ptrs[i];
@ -1005,7 +995,6 @@ fail:
free(*data_ptrs[i], M_CAMPERIPH);
*data_ptrs[i] = mapinfo->orig[i];
}
PRELE(curproc);
return(EACCES);
}
@ -1116,9 +1105,6 @@ cam_periph_unmapmem(union ccb *ccb, struct cam_periph_map_info *mapinfo)
*data_ptrs[i] = mapinfo->orig[i];
}
/* allow ourselves to be swapped once again */
PRELE(curproc);
return (error);
}

6
sys/compat/linuxkpi/common/src/linux_schedule.c
View file

@ -268,11 +268,6 @@ linux_wait_event_common(wait_queue_head_t *wqh, wait_queue_t *wq, int timeout,
task = current;
/*
* Our wait queue entry is on the stack - make sure it doesn't
* get swapped out while we sleep.
*/
PHOLD(task->task_thread->td_proc);
sleepq_lock(task);
if (atomic_read(&task->state) != TASK_WAKING) {
ret = linux_add_to_sleepqueue(task, task, "wevent", timeout,
@ -281,7 +276,6 @@ linux_wait_event_common(wait_queue_head_t *wqh, wait_queue_t *wq, int timeout,
sleepq_release(task);
ret = 0;
}
PRELE(task->task_thread->td_proc);
if (lock != NULL)
spin_lock_irq(lock);

12
sys/dev/nvme/nvme_ctrlr.c
View file

@ -1259,11 +1259,6 @@ nvme_ctrlr_passthrough_cmd(struct nvme_controller *ctrlr,
return EIO;
}
if (is_user_buffer) {
/*
* Ensure the user buffer is wired for the duration of
* this pass-through command.
*/
PHOLD(curproc);
buf = uma_zalloc(pbuf_zone, M_WAITOK);
buf->b_iocmd = pt->is_read ? BIO_READ : BIO_WRITE;
if (vmapbuf(buf, pt->buf, pt->len, 1) < 0) {
@ -1309,7 +1304,6 @@ nvme_ctrlr_passthrough_cmd(struct nvme_controller *ctrlr,
vunmapbuf(buf);
err:
uma_zfree(pbuf_zone, buf);
PRELE(curproc);
}
return (ret);
@ -1356,11 +1350,6 @@ nvme_ctrlr_linux_passthru_cmd(struct nvme_controller *ctrlr,
if ((npc->opcode & 0x3) == 0 || (npc->opcode & 0x3) == 3)
return (EINVAL);
if (is_user) {
/*
* Ensure the user buffer is wired for the duration of
* this pass-through command.
*/
PHOLD(curproc);
buf = uma_zalloc(pbuf_zone, M_WAITOK);
buf->b_iocmd = npc->opcode & 1 ? BIO_WRITE : BIO_READ;
if (vmapbuf(buf, (void *)(uintptr_t)npc->addr,
@ -1408,7 +1397,6 @@ nvme_ctrlr_linux_passthru_cmd(struct nvme_controller *ctrlr,
vunmapbuf(buf);
err:
uma_zfree(pbuf_zone, buf);
PRELE(curproc);
}
return (ret);

7
sys/kern/kern_physio.c
View file

@ -87,12 +87,6 @@ physio(struct cdev *dev, struct uio *uio, int ioflag)
return (EFBIG);
}
/*
* Keep the process UPAGES from being swapped. Processes swapped
* out while holding pbufs, used by swapper, may lead to deadlock.
*/
PHOLD(curproc);
bp = g_alloc_bio();
if (uio->uio_segflg != UIO_USERSPACE) {
pbuf = NULL;
@ -209,6 +203,5 @@ doerror:
else if (pages)
free(pages, M_DEVBUF);
g_destroy_bio(bp);
PRELE(curproc);
return (error);
}

10
sys/kern/kern_procctl.c
View file

@ -573,17 +573,7 @@ reap_kill(struct thread *td, struct proc *p, void *data)
w.rk = rk;
w.error = &error;
TASK_INIT(&w.t, 0, reap_kill_proc_work, &w);
/*
* Prevent swapout, since w, ksi, and possibly rk, are
* allocated on the stack. We sleep in
* reap_kill_subtree_once() waiting for task to
* complete single-threading.
*/
PHOLD(td->td_proc);
reap_kill_subtree(td, p, reaper, &w);
PRELE(td->td_proc);
crfree(w.cr);
}
PROC_LOCK(p);

2
sys/kern/subr_firmware.c
View file

@ -419,9 +419,7 @@ firmware_get_flags(const char *imagename, uint32_t flags)
fwli.flags = flags;
TASK_INIT(&fwload_task, 0, loadimage, (void *)&fwli);
taskqueue_enqueue(firmware_tq, &fwload_task);
PHOLD(curproc);
msleep((void *)&fwli, &firmware_mtx, 0, "fwload", 0);
PRELE(curproc);
}
/*
* After attempting to load the module, see if the image is registered.

6
sys/ufs/ffs/ffs_rawread.c
View file

@ -265,11 +265,6 @@ ffs_rawread_main(struct vnode *vp,
resid = uio->uio_resid;
offset = uio->uio_offset;
/*
* keep the process from being swapped
*/
PHOLD(td->td_proc);
error = 0;
nerror = 0;
@ -389,7 +384,6 @@ ffs_rawread_main(struct vnode *vp,
if (error == 0)
error = nerror;
PRELE(td->td_proc);
uio->uio_iov->iov_base = udata;
uio->uio_resid = resid;
uio->uio_offset = offset;

4
sys/ufs/ffs/ffs_softdep.c
View file

@ -1904,7 +1904,6 @@ process_worklist_item(struct mount *mp,
*/
if (curthread->td_pflags & TDP_COWINPROGRESS)
return (-1);
PHOLD(curproc); /* Don't let the stack go away. */
ump = VFSTOUFS(mp);
LOCK_OWNED(ump);
matchcnt = 0;
@ -1977,7 +1976,6 @@ process_worklist_item(struct mount *mp,
ump->softdep_worklist_tail =
(struct worklist *)sentinel.wk_list.le_prev;
LIST_REMOVE(&sentinel, wk_list);
PRELE(curproc);
return (matchcnt);
}
@ -10230,7 +10228,6 @@ softdep_disk_io_initiation(
return;
marker.wk_type = D_LAST + 1; /* Not a normal workitem */
PHOLD(curproc); /* Don't swap out kernel stack */
ACQUIRE_LOCK(ump);
/*
* Do any necessary pre-I/O processing.
@ -10315,7 +10312,6 @@ softdep_disk_io_initiation(
}
}
FREE_LOCK(ump);
PRELE(curproc); /* Allow swapout of kernel stack */
}
/*