Date: Thu, 3 Nov 2011 15:24:37 +0200 From: Kostik Belousov <kostikbel@gmail.com> To: Alan Cox <alc@rice.edu> Cc: "K. Macy" <kmacy@freebsd.org>, freebsd-current@freebsd.org, Penta Upa <bsdboot@gmail.com>, Andriy Gapon <avg@freebsd.org>, Benjamin Kaduk <kaduk@mit.edu> Subject: Re: panic at vm_page_wire with FreeBSD 9.0 Beta 3 Message-ID: <20111103132437.GV50300@deviant.kiev.zoral.com.ua> In-Reply-To: <4EB22938.4050803@rice.edu> References: <CAMsyT5QgHLqgSrt7qU_4FOVocW_GwmVWgZQ1A_CNrzkHQRTm4w@mail.gmail.com> <CAHM0Q_OWrQS_gnwupdJDwRFV9M3dKRN-SzkHgz6gJEedkvTPKQ@mail.gmail.com> <CAMsyT5Q5kMHRJQqFUdCCqqvKvFS_i5bvR8sHW6vNti_boD0nfA@mail.gmail.com> <alpine.GSO.1.10.1111020203230.882@multics.mit.edu> <4EB11C32.80106@FreeBSD.org> <4EB22938.4050803@rice.edu>
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On Thu, Nov 03, 2011 at 12:40:08AM -0500, Alan Cox wrote:
> On 11/02/2011 05:32, Andriy Gapon wrote:
> >[restored cc: to the original poster]
> >As Bruce Evans has pointed to me privately [I am not sure why privately]=
,=20
> >there
> >is already an example in i386 and amd64 atomic.h, where operations are=
=20
> >inlined
> >for a kernel build, but presented as real (external) functions for a mod=
ule
> >build. You can search e.g. sys/amd64/include/atomic.h for KLD_MODULE.
> >
> >I think that the same treatment could/should be applied to vm_page_*lock*
> >operations defined in sys/vm/vm_page.h.
> *snip*
>=20
> Yes, it should be. There are without question legitimate reasons for a=
=20
> module to acquire a page lock.
I agree. Also, I think that we should use the opportunity to also isolate
the modules from the struct vm_page layout changes. As example, I converted
nfsclient.ko.
Patch is not tested.
diff --git a/sys/nfsclient/nfs_bio.c b/sys/nfsclient/nfs_bio.c
index 305c189..7264cd1 100644
--- a/sys/nfsclient/nfs_bio.c
+++ b/sys/nfsclient/nfs_bio.c
@@ -128,7 +128,7 @@ nfs_getpages(struct vop_getpages_args *ap)
* can only occur at the file EOF.
*/
VM_OBJECT_LOCK(object);
- if (pages[ap->a_reqpage]->valid !=3D 0) {
+ if (vm_page_read_valid(pages[ap->a_reqpage]) !=3D 0) {
for (i =3D 0; i < npages; ++i) {
if (i !=3D ap->a_reqpage) {
vm_page_lock(pages[i]);
@@ -198,16 +198,16 @@ nfs_getpages(struct vop_getpages_args *ap)
/*
* Read operation filled an entire page
*/
- m->valid =3D VM_PAGE_BITS_ALL;
- KASSERT(m->dirty =3D=3D 0,
+ vm_page_write_valid(m, VM_PAGE_BITS_ALL);
+ KASSERT(vm_page_read_dirty(m) =3D=3D 0,
("nfs_getpages: page %p is dirty", m));
} else if (size > toff) {
/*
* Read operation filled a partial page.
*/
- m->valid =3D 0;
+ vm_page_write_valid(m, 0);
vm_page_set_valid(m, 0, size - toff);
- KASSERT(m->dirty =3D=3D 0,
+ KASSERT(vm_page_read_dirty(m) =3D=3D 0,
("nfs_getpages: page %p is dirty", m));
} else {
/*
diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
index f14da4a..5b8b4e3 100644
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
@@ -2677,6 +2677,66 @@ vm_page_test_dirty(vm_page_t m)
vm_page_dirty(m);
}
=20
+void
+vm_page_lock_func(vm_page_t m, const char *file, int line)
+{
+
+#if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE)
+ _mtx_lock_flags(vm_page_lockptr(m), 0, file, line);
+#else
+ __mtx_lock(vm_page_lockptr(m), 0, file, line);
+#endif
+}
+
+void
+vm_page_unlock_func(vm_page_t m, const char *file, int line)
+{
+
+#if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE)
+ _mtx_unlock_flags(vm_page_lockptr(m), 0, file, line);
+#else
+ __mtx_unlock(vm_page_lockptr(m), curthread, 0, file, line);
+#endif
+}
+
+int
+vm_page_trylock_func(vm_page_t m, const char *file, int line)
+{
+
+ return (_mtx_trylock(vm_page_lockptr(m), 0, file, line));
+}
+
+void
+vm_page_lock_assert_func(vm_page_t m, int a, const char *file, int line)
+{
+
+#ifdef INVARIANTS
+ _mtx_assert(vm_page_lockptr(m), a, file, line);
+#endif
+}
+
+vm_page_bits_t
+vm_page_read_dirty_func(vm_page_t m)
+{
+
+ return (m->dirty);
+}
+
+vm_page_bits_t
+vm_page_read_valid_func(vm_page_t m)
+{
+
+ return (m->valid);
+}
+
+void
+vm_page_write_valid_func(vm_page_t m, vm_page_bits_t v)
+{
+
+ m->valid =3D v;
+}
+
+
int so_zerocp_fullpage =3D 0;
=20
/*
diff --git a/sys/vm/vm_page.h b/sys/vm/vm_page.h
index 23637bb..618ba2b 100644
--- a/sys/vm/vm_page.h
+++ b/sys/vm/vm_page.h
@@ -113,6 +113,21 @@
=20
TAILQ_HEAD(pglist, vm_page);
=20
+#if PAGE_SIZE =3D=3D 4096
+#define VM_PAGE_BITS_ALL 0xffu
+typedef uint8_t vm_page_bits_t;
+#elif PAGE_SIZE =3D=3D 8192
+#define VM_PAGE_BITS_ALL 0xffffu
+typedef uint16_t vm_page_bits_t;
+#elif PAGE_SIZE =3D=3D 16384
+#define VM_PAGE_BITS_ALL 0xffffffffu
+typedef uint32_t vm_page_bits_t;
+#elif PAGE_SIZE =3D=3D 32768
+#define VM_PAGE_BITS_ALL 0xfffffffffffffffflu
+typedef uint64_t vm_page_bits_t;
+#endif
+
+
struct vm_page {
TAILQ_ENTRY(vm_page) pageq; /* queue info for FIFO queue or free list (Q)=
*/
TAILQ_ENTRY(vm_page) listq; /* pages in same object (O) */
@@ -138,19 +153,8 @@ struct vm_page {
/* NOTE that these must support one bit per DEV_BSIZE in a page!!! */
/* so, on normal X86 kernels, they must be at least 8 bits wide */
/* In reality, support for 32KB pages is not fully implemented. */
-#if PAGE_SIZE =3D=3D 4096
- uint8_t valid; /* map of valid DEV_BSIZE chunks (O) */
- uint8_t dirty; /* map of dirty DEV_BSIZE chunks (M) */
-#elif PAGE_SIZE =3D=3D 8192
- uint16_t valid; /* map of valid DEV_BSIZE chunks (O) */
- uint16_t dirty; /* map of dirty DEV_BSIZE chunks (M) */
-#elif PAGE_SIZE =3D=3D 16384
- uint32_t valid; /* map of valid DEV_BSIZE chunks (O) */
- uint32_t dirty; /* map of dirty DEV_BSIZE chunks (M) */
-#elif PAGE_SIZE =3D=3D 32768
- uint64_t valid; /* map of valid DEV_BSIZE chunks (O) */
- uint64_t dirty; /* map of dirty DEV_BSIZE chunks (M) */
-#endif
+ vm_page_bits_t valid; /* map of valid DEV_BSIZE chunks (O) */
+ vm_page_bits_t dirty; /* map of dirty DEV_BSIZE chunks (M) */
};
=20
/*
@@ -216,12 +220,50 @@ extern struct vpglocks pa_lock[];
=20
#define PA_LOCK_ASSERT(pa, a) mtx_assert(PA_LOCKPTR(pa), (a))
=20
+#ifdef KLD_MODULE
+#define vm_page_lock(m) vm_page_lock_func((m), LOCK_FILE, LOCK_LINE)
+#define vm_page_unlock(m) vm_page_unlock_func((m), LOCK_FILE, LOCK_LINE)
+#define vm_page_trylock(m) vm_page_trylock_func((m), LOCK_FILE, LOCK_LINE)
+#ifdef INVARIANTS
+#define vm_page_lock_assert(m, a) \
+ vm_page_lock_assert_func((m), (a), LOCK_FILE, LOCK_LINE)
+#else
+#define vm_page_lock_assert(m, a)
+#endif
+
+#define vm_page_read_dirty(m) vm_page_read_dirty_func((m))
+#define vm_page_read_valid(m) vm_page_read_valid_func((m))
+#define vm_page_write_valid(m, v) vm_page_write_valid_func((m), (v))
+
+#else /* KLD_MODULE */
#define vm_page_lockptr(m) (PA_LOCKPTR(VM_PAGE_TO_PHYS((m))))
#define vm_page_lock(m) mtx_lock(vm_page_lockptr((m)))
#define vm_page_unlock(m) mtx_unlock(vm_page_lockptr((m)))
#define vm_page_trylock(m) mtx_trylock(vm_page_lockptr((m)))
#define vm_page_lock_assert(m, a) mtx_assert(vm_page_lockptr((m)), (a))
=20
+static inline vm_page_bits_t
+vm_page_read_dirty(vm_page_t m)
+{
+
+ return (m->dirty);
+}
+
+static inline vm_page_bits_t
+vm_page_read_valid(vm_page_t m)
+{
+
+ return (m->valid);
+}
+
+static inline void
+vm_page_write_valid(vm_page_t m, vm_page_bits_t v)
+{
+
+ m->valid =3D v;
+}
+#endif
+
#define vm_page_queue_free_mtx vm_page_queue_free_lock.data
/*
* These are the flags defined for vm_page.
@@ -322,16 +364,6 @@ extern struct vpglocks vm_page_queue_lock;
#define vm_page_lock_queues() mtx_lock(&vm_page_queue_mtx)
#define vm_page_unlock_queues() mtx_unlock(&vm_page_queue_mtx)
=20
-#if PAGE_SIZE =3D=3D 4096
-#define VM_PAGE_BITS_ALL 0xffu
-#elif PAGE_SIZE =3D=3D 8192
-#define VM_PAGE_BITS_ALL 0xffffu
-#elif PAGE_SIZE =3D=3D 16384
-#define VM_PAGE_BITS_ALL 0xffffffffu
-#elif PAGE_SIZE =3D=3D 32768
-#define VM_PAGE_BITS_ALL 0xfffffffffffffffflu
-#endif
-
/* page allocation classes: */
#define VM_ALLOC_NORMAL 0
#define VM_ALLOC_INTERRUPT 1
@@ -411,6 +443,15 @@ void vm_page_cowfault (vm_page_t);
int vm_page_cowsetup(vm_page_t);
void vm_page_cowclear (vm_page_t);
=20
+void vm_page_lock_func(vm_page_t m, const char *file, int line);
+void vm_page_unlock_func(vm_page_t m, const char *file, int line);
+int vm_page_trylock_func(vm_page_t m, const char *file, int line);
+void vm_page_lock_assert_func(vm_page_t m, int a, const char *file, int li=
ne);
+
+vm_page_bits_t vm_page_read_dirty_func(vm_page_t m);
+vm_page_bits_t vm_page_read_valid_func(vm_page_t m);
+void vm_page_write_valid_func(vm_page_t m, vm_page_bits_t v);
+
#ifdef INVARIANTS
void vm_page_object_lock_assert(vm_page_t m);
#define VM_PAGE_OBJECT_LOCK_ASSERT(m) vm_page_object_lock_assert(m)
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