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Make contigmalloc(9)'s page laundering more robust. Specifically, use

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vm_pageout_fallback_object_lock() in vm_contig_launder_page() to better
handle a lock-ordering problem.  Consequently, trylock's failure on the
page's containing object no longer implies that the page cannot be
laundered.

MFC after: 6 weeks
This commit is contained in:
Alan Cox 2007-11-25 20:37:29 +00:00
parent 4faa4b080e
commit da31e3aa04
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=173918
3 changed files with 8 additions and 4 deletions
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9
sys/vm/vm_contig.c
View File

@ -88,7 +88,7 @@ __FBSDID("$FreeBSD$");
#include <vm/vm_extern.h>
static int
vm_contig_launder_page(vm_page_t m)
vm_contig_launder_page(vm_page_t m, vm_page_t *next)
{
vm_object_t object;
vm_page_t m_tmp;
@ -98,8 +98,11 @@ vm_contig_launder_page(vm_page_t m)
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
object = m->object;
if (!VM_OBJECT_TRYLOCK(object))
if (!VM_OBJECT_TRYLOCK(object) &&
!vm_pageout_fallback_object_lock(m, next)) {
VM_OBJECT_UNLOCK(object);
return (EAGAIN);
}
if (vm_page_sleep_if_busy(m, TRUE, "vpctw0")) {
VM_OBJECT_UNLOCK(object);
vm_page_lock_queues();
@ -157,7 +160,7 @@ vm_contig_launder(int queue)
KASSERT(VM_PAGE_INQUEUE2(m, queue),
("vm_contig_launder: page %p's queue is not %d", m, queue));
error = vm_contig_launder_page(m);
error = vm_contig_launder_page(m, &next);
if (error == 0)
return (TRUE);
if (error == EBUSY)

2
sys/vm/vm_pageout.c
View File

@ -230,7 +230,7 @@ static void vm_pageout_page_stats(void);
* This function depends on both the lock portion of struct vm_object
* and normal struct vm_page being type stable.
*/
static boolean_t
boolean_t
vm_pageout_fallback_object_lock(vm_page_t m, vm_page_t *next)
{
struct vm_page marker;

1
sys/vm/vm_pageout.h
View File

@ -98,6 +98,7 @@ extern void vm_wait(void);
extern void vm_waitpfault(void);
#ifdef _KERNEL
boolean_t vm_pageout_fallback_object_lock(vm_page_t, vm_page_t *);
int vm_pageout_flush(vm_page_t *, int, int);
#endif
#endif /* _VM_VM_PAGEOUT_H_ */