Author: attilio
Date: Mon Aug 5 08:55:35 2013
New Revision: 253953
URL: http://svnweb.freebsd.org/changeset/base/253953
Log:
Revert r253939:
We cannot busy a page before doing pagefaults.
Infact, it can deadlock against vnode lock, as it tries to vget().
Other functions, right now, have an opposite lock ordering, like
vm_object_sync(), which acquires the vnode lock first and then
sleeps on the busy mechanism.
Before this patch is reinserted we need to break this ordering.
Sponsored by: EMC / Isilon storage division
Reported by: kib
Modified:
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
head/sys/fs/tmpfs/tmpfs_vnops.c
head/sys/kern/imgact_elf.c
head/sys/kern/kern_exec.c
head/sys/kern/sys_process.c
head/sys/vm/vm_extern.h
head/sys/vm/vm_fault.c
head/sys/vm/vm_glue.c
head/sys/vm/vm_map.h
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c Mon Aug
5 08:27:35 2013 (r253952)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c Mon Aug
5 08:55:35 2013 (r253953)
@@ -324,8 +324,7 @@ zfs_ioctl(vnode_t *vp, u_long com, intpt
}
static vm_page_t
-page_busy(vnode_t *vp, int64_t start, int64_t off, int64_t nbytes,
- boolean_t alloc)
+page_busy(vnode_t *vp, int64_t start, int64_t off, int64_t nbytes)
{
vm_object_t obj;
vm_page_t pp;
@@ -347,8 +346,6 @@ page_busy(vnode_t *vp, int64_t start, in
continue;
}
} else if (pp == NULL) {
- if (!alloc)
- break;
pp = vm_page_alloc(obj, OFF_TO_IDX(start),
VM_ALLOC_SYSTEM | VM_ALLOC_IFCACHED |
VM_ALLOC_NOBUSY);
@@ -359,10 +356,8 @@ page_busy(vnode_t *vp, int64_t start, in
if (pp != NULL) {
ASSERT3U(pp->valid, ==, VM_PAGE_BITS_ALL);
- vm_page_io_start(pp);
- if (!alloc)
- break;
vm_object_pip_add(obj, 1);
+ vm_page_io_start(pp);
pmap_remove_write(pp);
vm_page_clear_dirty(pp, off, nbytes);
}
@@ -372,12 +367,55 @@ page_busy(vnode_t *vp, int64_t start, in
}
static void
-page_unbusy(vm_page_t pp, boolean_t unalloc)
+page_unbusy(vm_page_t pp)
{
vm_page_io_finish(pp);
- if (unalloc)
- vm_object_pip_subtract(pp->object, 1);
+ vm_object_pip_subtract(pp->object, 1);
+}
+
+static vm_page_t
+page_hold(vnode_t *vp, int64_t start)
+{
+ vm_object_t obj;
+ vm_page_t pp;
+
+ obj = vp->v_object;
+ zfs_vmobject_assert_wlocked(obj);
+
+ for (;;) {
+ if ((pp = vm_page_lookup(obj, OFF_TO_IDX(start))) != NULL &&
+ pp->valid) {
+ if ((pp->oflags & VPO_BUSY) != 0) {
+ /*
+ * Reference the page before unlocking and
+ * sleeping so that the page daemon is less
+ * likely to reclaim it.
+ */
+ vm_page_reference(pp);
+ vm_page_sleep(pp, "zfsmwb");
+ continue;
+ }
+
+ ASSERT3U(pp->valid, ==, VM_PAGE_BITS_ALL);
+ vm_page_lock(pp);
+ vm_page_hold(pp);
+ vm_page_unlock(pp);
+
+ } else
+ pp = NULL;
+ break;
+ }
+ return (pp);
+}
+
+static void
+page_unhold(vm_page_t pp)
+{
+
+ vm_page_lock(pp);
+ vm_page_unhold(pp);
+ vm_page_unlock(pp);
}
static caddr_t
@@ -441,8 +479,7 @@ update_pages(vnode_t *vp, int64_t start,
zfs_vmobject_wlock(obj);
vm_page_undirty(pp);
- } else if ((pp = page_busy(vp, start, off, nbytes,
- TRUE)) != NULL) {
+ } else if ((pp = page_busy(vp, start, off, nbytes)) != NULL) {
zfs_vmobject_wunlock(obj);
va = zfs_map_page(pp, &sf);
@@ -451,7 +488,7 @@ update_pages(vnode_t *vp, int64_t start,
zfs_unmap_page(sf);
zfs_vmobject_wlock(obj);
- page_unbusy(pp, TRUE);
+ page_unbusy(pp);
}
len -= nbytes;
off = 0;
@@ -561,7 +598,7 @@ mappedread(vnode_t *vp, int nbytes, uio_
vm_page_t pp;
uint64_t bytes = MIN(PAGESIZE - off, len);
- if (pp = page_busy(vp, start, 0, 0, FALSE)) {
+ if (pp = page_hold(vp, start)) {
struct sf_buf *sf;
caddr_t va;
@@ -570,7 +607,7 @@ mappedread(vnode_t *vp, int nbytes, uio_
error = uiomove(va + off, bytes, UIO_READ, uio);
zfs_unmap_page(sf);
zfs_vmobject_wlock(obj);
- page_unbusy(pp, FALSE);
+ page_unhold(pp);
} else {
zfs_vmobject_wunlock(obj);
error = dmu_read_uio(os, zp->z_id, uio, bytes);
Modified: head/sys/fs/tmpfs/tmpfs_vnops.c
==============================================================================
--- head/sys/fs/tmpfs/tmpfs_vnops.c Mon Aug 5 08:27:35 2013
(r253952)
+++ head/sys/fs/tmpfs/tmpfs_vnops.c Mon Aug 5 08:55:35 2013
(r253953)
@@ -485,13 +485,13 @@ tmpfs_nocacheread(vm_object_t tobj, vm_p
vm_page_zero_invalid(m, TRUE);
vm_page_wakeup(m);
}
- vm_page_io_start(m);
+ vm_page_lock(m);
+ vm_page_hold(m);
+ vm_page_unlock(m);
VM_OBJECT_WUNLOCK(tobj);
error = uiomove_fromphys(&m, offset, tlen, uio);
- VM_OBJECT_WLOCK(tobj);
- vm_page_io_finish(m);
- VM_OBJECT_WUNLOCK(tobj);
vm_page_lock(m);
+ vm_page_unhold(m);
if (m->queue == PQ_NONE) {
vm_page_deactivate(m);
} else {
@@ -602,14 +602,16 @@ tmpfs_mappedwrite(vm_object_t tobj, size
vm_page_zero_invalid(tpg, TRUE);
vm_page_wakeup(tpg);
}
- vm_page_io_start(tpg);
+ vm_page_lock(tpg);
+ vm_page_hold(tpg);
+ vm_page_unlock(tpg);
VM_OBJECT_WUNLOCK(tobj);
error = uiomove_fromphys(&tpg, offset, tlen, uio);
VM_OBJECT_WLOCK(tobj);
- vm_page_io_finish(tpg);
if (error == 0)
vm_page_dirty(tpg);
vm_page_lock(tpg);
+ vm_page_unhold(tpg);
if (tpg->queue == PQ_NONE) {
vm_page_deactivate(tpg);
} else {
Modified: head/sys/kern/imgact_elf.c
==============================================================================
--- head/sys/kern/imgact_elf.c Mon Aug 5 08:27:35 2013 (r253952)
+++ head/sys/kern/imgact_elf.c Mon Aug 5 08:55:35 2013 (r253953)
@@ -378,7 +378,7 @@ __elfN(map_partial)(vm_map_t map, vm_obj
off = offset - trunc_page(offset);
error = copyout((caddr_t)sf_buf_kva(sf) + off, (caddr_t)start,
end - start);
- vm_imgact_unmap_page(object, sf);
+ vm_imgact_unmap_page(sf);
if (error) {
return (KERN_FAILURE);
}
@@ -433,7 +433,7 @@ __elfN(map_insert)(vm_map_t map, vm_obje
sz = PAGE_SIZE - off;
error = copyout((caddr_t)sf_buf_kva(sf) + off,
(caddr_t)start, sz);
- vm_imgact_unmap_page(object, sf);
+ vm_imgact_unmap_page(sf);
if (error) {
return (KERN_FAILURE);
}
@@ -553,7 +553,7 @@ __elfN(load_section)(struct image_params
trunc_page(offset + filsz);
error = copyout((caddr_t)sf_buf_kva(sf) + off,
(caddr_t)map_addr, copy_len);
- vm_imgact_unmap_page(object, sf);
+ vm_imgact_unmap_page(sf);
if (error) {
return (error);
}
Modified: head/sys/kern/kern_exec.c
==============================================================================
--- head/sys/kern/kern_exec.c Mon Aug 5 08:27:35 2013 (r253952)
+++ head/sys/kern/kern_exec.c Mon Aug 5 08:55:35 2013 (r253953)
@@ -973,7 +973,7 @@ exec_map_first_page(imgp)
vm_page_wakeup(ma[0]);
}
vm_page_lock(ma[0]);
- vm_page_wire(ma[0]);
+ vm_page_hold(ma[0]);
vm_page_unlock(ma[0]);
VM_OBJECT_WUNLOCK(object);
@@ -994,7 +994,7 @@ exec_unmap_first_page(imgp)
sf_buf_free(imgp->firstpage);
imgp->firstpage = NULL;
vm_page_lock(m);
- vm_page_unwire(m, 0);
+ vm_page_unhold(m);
vm_page_unlock(m);
}
}
Modified: head/sys/kern/sys_process.c
==============================================================================
--- head/sys/kern/sys_process.c Mon Aug 5 08:27:35 2013 (r253952)
+++ head/sys/kern/sys_process.c Mon Aug 5 08:55:35 2013 (r253953)
@@ -263,7 +263,6 @@ proc_rwmem(struct proc *p, struct uio *u
writing = uio->uio_rw == UIO_WRITE;
reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
fault_flags = writing ? VM_FAULT_DIRTY : VM_FAULT_NORMAL;
- fault_flags |= VM_FAULT_IOBUSY;
/*
* Only map in one page at a time. We don't have to, but it
@@ -288,9 +287,9 @@ proc_rwmem(struct proc *p, struct uio *u
len = min(PAGE_SIZE - page_offset, uio->uio_resid);
/*
- * Fault and busy the page on behalf of the process.
+ * Fault and hold the page on behalf of the process.
*/
- error = vm_fault_handle(map, pageno, reqprot, fault_flags, &m);
+ error = vm_fault_hold(map, pageno, reqprot, fault_flags, &m);
if (error != KERN_SUCCESS) {
if (error == KERN_RESOURCE_SHORTAGE)
error = ENOMEM;
@@ -316,9 +315,9 @@ proc_rwmem(struct proc *p, struct uio *u
/*
* Release the page.
*/
- VM_OBJECT_WLOCK(m->object);
- vm_page_io_finish(m);
- VM_OBJECT_WUNLOCK(m->object);
+ vm_page_lock(m);
+ vm_page_unhold(m);
+ vm_page_unlock(m);
} while (error == 0 && uio->uio_resid > 0);
Modified: head/sys/vm/vm_extern.h
==============================================================================
--- head/sys/vm/vm_extern.h Mon Aug 5 08:27:35 2013 (r253952)
+++ head/sys/vm/vm_extern.h Mon Aug 5 08:55:35 2013 (r253953)
@@ -63,7 +63,7 @@ void vm_fault_copy_entry(vm_map_t, vm_ma
vm_ooffset_t *);
int vm_fault_disable_pagefaults(void);
void vm_fault_enable_pagefaults(int save);
-int vm_fault_handle(vm_map_t map, vm_offset_t vaddr, vm_prot_t fault_type,
+int vm_fault_hold(vm_map_t map, vm_offset_t vaddr, vm_prot_t fault_type,
int fault_flags, vm_page_t *m_hold);
int vm_fault_quick_hold_pages(vm_map_t map, vm_offset_t addr, vm_size_t len,
vm_prot_t prot, vm_page_t *ma, int max_count);
@@ -87,7 +87,7 @@ void vnode_pager_setsize(struct vnode *,
int vslock(void *, size_t);
void vsunlock(void *, size_t);
struct sf_buf *vm_imgact_map_page(vm_object_t object, vm_ooffset_t offset);
-void vm_imgact_unmap_page(vm_object_t, struct sf_buf *sf);
+void vm_imgact_unmap_page(struct sf_buf *sf);
void vm_thread_dispose(struct thread *td);
int vm_thread_new(struct thread *td, int pages);
int vm_mlock(struct proc *, struct ucred *, const void *, size_t);
Modified: head/sys/vm/vm_fault.c
==============================================================================
--- head/sys/vm/vm_fault.c Mon Aug 5 08:27:35 2013 (r253952)
+++ head/sys/vm/vm_fault.c Mon Aug 5 08:55:35 2013 (r253953)
@@ -221,8 +221,8 @@ vm_fault(vm_map_t map, vm_offset_t vaddr
if (map != kernel_map && KTRPOINT(td, KTR_FAULT))
ktrfault(vaddr, fault_type);
#endif
- result = vm_fault_handle(map, trunc_page(vaddr), fault_type,
- fault_flags, NULL);
+ result = vm_fault_hold(map, trunc_page(vaddr), fault_type, fault_flags,
+ NULL);
#ifdef KTRACE
if (map != kernel_map && KTRPOINT(td, KTR_FAULTEND))
ktrfaultend(result);
@@ -231,7 +231,7 @@ vm_fault(vm_map_t map, vm_offset_t vaddr
}
int
-vm_fault_handle(vm_map_t map, vm_offset_t vaddr, vm_prot_t fault_type,
+vm_fault_hold(vm_map_t map, vm_offset_t vaddr, vm_prot_t fault_type,
int fault_flags, vm_page_t *m_hold)
{
vm_prot_t prot;
@@ -943,10 +943,7 @@ vnode_locked:
vm_page_activate(fs.m);
if (m_hold != NULL) {
*m_hold = fs.m;
- if (fault_flags & VM_FAULT_IOBUSY)
- vm_page_io_start(fs.m);
- else
- vm_page_hold(fs.m);
+ vm_page_hold(fs.m);
}
vm_page_unlock(fs.m);
vm_page_wakeup(fs.m);
@@ -1148,7 +1145,7 @@ vm_fault_quick_hold_pages(vm_map_t map,
* and hold these pages.
*/
for (mp = ma, va = addr; va < end; mp++, va += PAGE_SIZE)
- if (*mp == NULL && vm_fault_handle(map, va, prot,
+ if (*mp == NULL && vm_fault_hold(map, va, prot,
VM_FAULT_NORMAL, mp) != KERN_SUCCESS)
goto error;
}
Modified: head/sys/vm/vm_glue.c
==============================================================================
--- head/sys/vm/vm_glue.c Mon Aug 5 08:27:35 2013 (r253952)
+++ head/sys/vm/vm_glue.c Mon Aug 5 08:55:35 2013 (r253953)
@@ -223,7 +223,7 @@ vsunlock(void *addr, size_t len)
* Return the pinned page if successful; otherwise, return NULL.
*/
static vm_page_t
-vm_imgact_page_iostart(vm_object_t object, vm_ooffset_t offset)
+vm_imgact_hold_page(vm_object_t object, vm_ooffset_t offset)
{
vm_page_t m, ma[1];
vm_pindex_t pindex;
@@ -249,7 +249,9 @@ vm_imgact_page_iostart(vm_object_t objec
}
vm_page_wakeup(m);
}
- vm_page_io_start(m);
+ vm_page_lock(m);
+ vm_page_hold(m);
+ vm_page_unlock(m);
out:
VM_OBJECT_WUNLOCK(object);
return (m);
@@ -264,7 +266,7 @@ vm_imgact_map_page(vm_object_t object, v
{
vm_page_t m;
- m = vm_imgact_page_iostart(object, offset);
+ m = vm_imgact_hold_page(object, offset);
if (m == NULL)
return (NULL);
sched_pin();
@@ -275,16 +277,16 @@ vm_imgact_map_page(vm_object_t object, v
* Destroy the given CPU private mapping and unpin the page that it mapped.
*/
void
-vm_imgact_unmap_page(vm_object_t object, struct sf_buf *sf)
+vm_imgact_unmap_page(struct sf_buf *sf)
{
vm_page_t m;
m = sf_buf_page(sf);
sf_buf_free(sf);
sched_unpin();
- VM_OBJECT_WLOCK(object);
- vm_page_io_finish(m);
- VM_OBJECT_WUNLOCK(object);
+ vm_page_lock(m);
+ vm_page_unhold(m);
+ vm_page_unlock(m);
}
void
Modified: head/sys/vm/vm_map.h
==============================================================================
--- head/sys/vm/vm_map.h Mon Aug 5 08:27:35 2013 (r253952)
+++ head/sys/vm/vm_map.h Mon Aug 5 08:55:35 2013 (r253953)
@@ -329,7 +329,6 @@ long vmspace_resident_count(struct vmspa
#define VM_FAULT_NORMAL 0 /* Nothing special */
#define VM_FAULT_CHANGE_WIRING 1 /* Change the wiring as appropriate */
#define VM_FAULT_DIRTY 2 /* Dirty the page; use
w/VM_PROT_COPY */
-#define VM_FAULT_IOBUSY 4 /* Busy the faulted page */
/*
* Initially, mappings are slightly sequential. The maximum window size must
_______________________________________________
svn-src-head@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
