git: d37286b9bf92 - main - proc: Remove kernel stack swapping support, part 7
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Date: Mon, 29 Jul 2024 01:49:59 UTC
The branch main has been updated by markj:
URL: https://cgit.FreeBSD.org/src/commit/?id=d37286b9bf92ec923ab6823bbedef9e39e7e1ebb
commit d37286b9bf92ec923ab6823bbedef9e39e7e1ebb
Author: Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2024-07-29 01:41:06 +0000
Commit: Mark Johnston <markj@FreeBSD.org>
CommitDate: 2024-07-29 01:43:49 +0000
proc: Remove kernel stack swapping support, part 7
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
---
sys/cam/cam_periph.c | 14 --------------
sys/compat/linuxkpi/common/src/linux_schedule.c | 6 ------
sys/dev/nvme/nvme_ctrlr.c | 12 ------------
sys/kern/kern_physio.c | 7 -------
sys/kern/kern_procctl.c | 10 ----------
sys/kern/subr_firmware.c | 2 --
sys/ufs/ffs/ffs_rawread.c | 6 ------
sys/ufs/ffs/ffs_softdep.c | 4 ----
8 files changed, 61 deletions(-)
diff --git a/sys/cam/cam_periph.c b/sys/cam/cam_periph.c
index e957edee67f1..4052ec2e1570 100644
--- a/sys/cam/cam_periph.c
+++ b/sys/cam/cam_periph.c
@@ -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);
}
diff --git a/sys/compat/linuxkpi/common/src/linux_schedule.c b/sys/compat/linuxkpi/common/src/linux_schedule.c
index 66b339bfbdbd..3349a4aa8d72 100644
--- a/sys/compat/linuxkpi/common/src/linux_schedule.c
+++ b/sys/compat/linuxkpi/common/src/linux_schedule.c
@@ -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);
diff --git a/sys/dev/nvme/nvme_ctrlr.c b/sys/dev/nvme/nvme_ctrlr.c
index e07ac737ffc8..52834cb26b8e 100644
--- a/sys/dev/nvme/nvme_ctrlr.c
+++ b/sys/dev/nvme/nvme_ctrlr.c
@@ -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);
diff --git a/sys/kern/kern_physio.c b/sys/kern/kern_physio.c
index 79b7694192e4..787505c1096f 100644
--- a/sys/kern/kern_physio.c
+++ b/sys/kern/kern_physio.c
@@ -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);
}
diff --git a/sys/kern/kern_procctl.c b/sys/kern/kern_procctl.c
index 888feb94bb8d..e7519f1b0de4 100644
--- a/sys/kern/kern_procctl.c
+++ b/sys/kern/kern_procctl.c
@@ -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);
diff --git a/sys/kern/subr_firmware.c b/sys/kern/subr_firmware.c
index 99f7ef6ff8b9..d616339f2c07 100644
--- a/sys/kern/subr_firmware.c
+++ b/sys/kern/subr_firmware.c
@@ -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.
diff --git a/sys/ufs/ffs/ffs_rawread.c b/sys/ufs/ffs/ffs_rawread.c
index 3a415d766303..9db0bee0d66d 100644
--- a/sys/ufs/ffs/ffs_rawread.c
+++ b/sys/ufs/ffs/ffs_rawread.c
@@ -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;
diff --git a/sys/ufs/ffs/ffs_softdep.c b/sys/ufs/ffs/ffs_softdep.c
index 5c8e2b6cde81..86c90000e8d2 100644
--- a/sys/ufs/ffs/ffs_softdep.c
+++ b/sys/ufs/ffs/ffs_softdep.c
@@ -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 */
}
/*