Re: panic at vm_page_wire with FreeBSD 9.0 Beta 3

On Thu, Nov 03, 2011 at 12:51:10PM -0500, Alan Cox wrote:
> On 11/03/2011 08:24, Kostik Belousov wrote:
> >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],
> >>>there
> >>>is already an example in i386 and amd64 atomic.h, where operations are
> >>>inlined
> >>>for a kernel build, but presented as real (external) functions for a 
> >>>module
> >>>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*
> >>
> >>Yes, it should be.  There are without question legitimate reasons for a
> >>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.
> >
> 
> I would suggest introducing the vm_page_bits_t change first.  If, at the 
> same time, you change the return type from the function vm_page_bits() 
> to use vm_page_bits_t, then I believe it is straightforward to fix all 
> of the places in vm_page.c that don't properly handle a 32 KB page size.
Ok, I think this is orhtohonal to the ABI issue. The vm_page_bits_t
applied.

diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
index f14da4a..f22c34a 100644
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
_at__at_ -137,7 +137,7 _at__at_ SYSCTL_INT(_vm, OID_AUTO, tryrelock_restart, CTLFLAG_RD,
 
 static uma_zone_t fakepg_zone;
 
-static void vm_page_clear_dirty_mask(vm_page_t m, int pagebits);
+static void vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits);
 static void vm_page_queue_remove(int queue, vm_page_t m);
 static void vm_page_enqueue(int queue, vm_page_t m);
 static void vm_page_init_fakepg(void *dummy);
_at__at_ -2350,7 +2350,7 _at__at_ retrylookup:
  *
  * Inputs are required to range within a page.
  */
-int
+vm_page_bits_t
 vm_page_bits(int base, int size)
 {
 	int first_bit;
_at__at_ -2367,7 +2367,8 _at__at_ vm_page_bits(int base, int size)
 	first_bit = base >> DEV_BSHIFT;
 	last_bit = (base + size - 1) >> DEV_BSHIFT;
 
-	return ((2 << last_bit) - (1 << first_bit));
+	return (((vm_page_bits_t)2 << last_bit) -
+	    ((vm_page_bits_t)1 << first_bit));
 }
 
 /*
_at__at_ -2426,7 +2427,7 _at__at_ vm_page_set_valid(vm_page_t m, int base, int size)
  * Clear the given bits from the specified page's dirty field.
  */
 static __inline void
-vm_page_clear_dirty_mask(vm_page_t m, int pagebits)
+vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits)
 {
 	uintptr_t addr;
 #if PAGE_SIZE < 16384
_at__at_ -2455,7 +2456,6 _at__at_ vm_page_clear_dirty_mask(vm_page_t m, int pagebits)
 		 */
 		addr = (uintptr_t)&m->dirty;
 #if PAGE_SIZE == 32768
-#error pagebits too short
 		atomic_clear_64((uint64_t *)addr, pagebits);
 #elif PAGE_SIZE == 16384
 		atomic_clear_32((uint32_t *)addr, pagebits);
_at__at_ -2492,8 +2492,8 _at__at_ vm_page_clear_dirty_mask(vm_page_t m, int pagebits)
 void
 vm_page_set_validclean(vm_page_t m, int base, int size)
 {
-	u_long oldvalid;
-	int endoff, frag, pagebits;
+	vm_page_bits_t oldvalid, pagebits;
+	int endoff, frag;
 
 	VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
 	if (size == 0)	/* handle degenerate case */
_at__at_ -2505,7 +2505,7 _at__at_ vm_page_set_validclean(vm_page_t m, int base, int size)
 	 * first block.
 	 */
 	if ((frag = base & ~(DEV_BSIZE - 1)) != base &&
-	    (m->valid & (1 << (base >> DEV_BSHIFT))) == 0)
+	    (m->valid & ((vm_page_bits_t)1 << (base >> DEV_BSHIFT))) == 0)
 		pmap_zero_page_area(m, frag, base - frag);
 
 	/*
_at__at_ -2515,7 +2515,7 _at__at_ vm_page_set_validclean(vm_page_t m, int base, int size)
 	 */
 	endoff = base + size;
 	if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff &&
-	    (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0)
+	    (m->valid & ((vm_page_bits_t)1 << (endoff >> DEV_BSHIFT))) == 0)
 		pmap_zero_page_area(m, endoff,
 		    DEV_BSIZE - (endoff & (DEV_BSIZE - 1)));
 
_at__at_ -2585,7 +2585,7 _at__at_ vm_page_clear_dirty(vm_page_t m, int base, int size)
 void
 vm_page_set_invalid(vm_page_t m, int base, int size)
 {
-	int bits;
+	vm_page_bits_t bits;
 
 	VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
 	KASSERT((m->oflags & VPO_BUSY) == 0,
_at__at_ -2656,9 +2656,10 _at__at_ vm_page_zero_invalid(vm_page_t m, boolean_t setvalid)
 int
 vm_page_is_valid(vm_page_t m, int base, int size)
 {
-	int bits = vm_page_bits(base, size);
+	vm_page_bits_t bits;
 
 	VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
+	bits = vm_page_bits(base, size);
 	if (m->valid && ((m->valid & bits) == bits))
 		return 1;
 	else
diff --git a/sys/vm/vm_page.h b/sys/vm/vm_page.h
index 23637bb..7d1a529 100644
--- a/sys/vm/vm_page.h
+++ b/sys/vm/vm_page.h
_at__at_ -113,6 +113,21 _at__at_
 
 TAILQ_HEAD(pglist, vm_page);
 
+#if PAGE_SIZE == 4096
+#define VM_PAGE_BITS_ALL 0xffu
+typedef uint8_t vm_page_bits_t;
+#elif PAGE_SIZE == 8192
+#define VM_PAGE_BITS_ALL 0xffffu
+typedef uint16_t vm_page_bits_t;
+#elif PAGE_SIZE == 16384
+#define VM_PAGE_BITS_ALL 0xffffffffu
+typedef uint32_t vm_page_bits_t;
+#elif PAGE_SIZE == 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) 	*/
_at__at_ -138,19 +153,8 _at__at_ 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 == 4096
-	uint8_t	valid;			/* map of valid DEV_BSIZE chunks (O) */
-	uint8_t	dirty;			/* map of dirty DEV_BSIZE chunks (M) */
-#elif PAGE_SIZE == 8192
-	uint16_t valid;			/* map of valid DEV_BSIZE chunks (O) */
-	uint16_t dirty;			/* map of dirty DEV_BSIZE chunks (M) */
-#elif PAGE_SIZE == 16384
-	uint32_t valid;			/* map of valid DEV_BSIZE chunks (O) */
-	uint32_t dirty;			/* map of dirty DEV_BSIZE chunks (M) */
-#elif PAGE_SIZE == 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) */
 };
 
 /*
_at__at_ -403,7 +407,7 _at__at_ void vm_page_clear_dirty (vm_page_t, int, int);
 void vm_page_set_invalid (vm_page_t, int, int);
 int vm_page_is_valid (vm_page_t, int, int);
 void vm_page_test_dirty (vm_page_t);
-int vm_page_bits (int, int);
+vm_page_bits_t vm_page_bits (int, int);
 void vm_page_zero_invalid(vm_page_t m, boolean_t setvalid);
 void vm_page_free_toq(vm_page_t m);
 void vm_page_zero_idle_wakeup(void);
diff --git a/sys/vm/vnode_pager.c b/sys/vm/vnode_pager.c
index e3222cb..cd2658d 100644
--- a/sys/vm/vnode_pager.c
+++ b/sys/vm/vnode_pager.c
_at__at_ -486,15 +486,16 _at__at_ vnode_pager_input_smlfs(object, m)
 	vm_object_t object;
 	vm_page_t m;
 {
-	int bits, i;
 	struct vnode *vp;
 	struct bufobj *bo;
 	struct buf *bp;
 	struct sf_buf *sf;
 	daddr_t fileaddr;
 	vm_offset_t bsize;
-	int error = 0;
+	vm_page_bits_t bits;
+	int error, i;
 
+	error = 0;
 	vp = object->handle;
 	if (vp->v_iflag & VI_DOOMED)
 		return VM_PAGER_BAD;