d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Don't release xbusy on kmem pages. After lockless page lookup we will not

Browse Source 
be able to guarantee that they can be racquired without blocking.

Reviewed by:	kib
Discussed with:	markj
Differential Revision:	https://reviews.freebsd.org/D23506
This commit is contained in:
Jeff Roberson 2020-02-19 09:10:11 +00:00
parent 6c5f36ff30
commit e9ceb9dd11
4 changed files with 9 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
sys/vm/vm_glue.c
View File

@ -342,10 +342,8 @@ vm_thread_stack_create(struct domainset *ds, vm_object_t *ksobjp, int pages)
VM_OBJECT_WLOCK(ksobj);
(void)vm_page_grab_pages(ksobj, 0, VM_ALLOC_NORMAL | VM_ALLOC_WIRED,
ma, pages);
for (i = 0; i < pages; i++) {
for (i = 0; i < pages; i++)
vm_page_valid(ma[i]);
vm_page_xunbusy(ma[i]);
}
VM_OBJECT_WUNLOCK(ksobj);
pmap_qenter(ks, ma, pages);
*ksobjp = ksobj;
@ -365,7 +363,7 @@ vm_thread_stack_dispose(vm_object_t ksobj, vm_offset_t ks, int pages)
m = vm_page_lookup(ksobj, i);
if (m == NULL)
panic("%s: kstack already missing?", __func__);
vm_page_busy_acquire(m, 0);
vm_page_xbusy_claim(m);
vm_page_unwire_noq(m);
vm_page_free(m);
}

5
sys/vm/vm_kern.c
View File

@ -224,7 +224,6 @@ kmem_alloc_attr_domain(int domain, vm_size_t size, int flags, vm_paddr_t low,
if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0)
pmap_zero_page(m);
vm_page_valid(m);
vm_page_xunbusy(m);
pmap_enter(kernel_pmap, addr + i, m, prot,
prot | PMAP_ENTER_WIRED, 0);
}
@ -317,7 +316,6 @@ kmem_alloc_contig_domain(int domain, vm_size_t size, int flags, vm_paddr_t low,
if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0)
pmap_zero_page(m);
vm_page_valid(m);
vm_page_xunbusy(m);
pmap_enter(kernel_pmap, tmp, m, VM_PROT_RW,
VM_PROT_RW | PMAP_ENTER_WIRED, 0);
tmp += PAGE_SIZE;
@ -501,7 +499,6 @@ kmem_back_domain(int domain, vm_object_t object, vm_offset_t addr,
KASSERT((m->oflags & VPO_UNMANAGED) != 0,
("kmem_malloc: page %p is managed", m));
vm_page_valid(m);
vm_page_xunbusy(m);
pmap_enter(kernel_pmap, addr + i, m, prot,
prot | PMAP_ENTER_WIRED, 0);
#if VM_NRESERVLEVEL > 0
@ -591,7 +588,7 @@ _kmem_unback(vm_object_t object, vm_offset_t addr, vm_size_t size)
#endif
for (; offset < end; offset += PAGE_SIZE, m = next) {
next = vm_page_next(m);
vm_page_busy_acquire(m, 0);
vm_page_xbusy_claim(m);
vm_page_unwire_noq(m);
vm_page_free(m);
}

5
sys/vm/vm_page.h
View File

@ -764,9 +764,14 @@ void vm_page_object_busy_assert(vm_page_t m);
void vm_page_assert_pga_writeable(vm_page_t m, uint16_t bits);
#define VM_PAGE_ASSERT_PGA_WRITEABLE(m, bits) \
vm_page_assert_pga_writeable(m, bits)
#define vm_page_xbusy_claim(m) do { \
vm_page_assert_xbusied_unchecked((m)); \
(m)->busy_lock = VPB_CURTHREAD_EXCLUSIVE; \
} while (0)
#else
#define VM_PAGE_OBJECT_BUSY_ASSERT(m) (void)0
#define VM_PAGE_ASSERT_PGA_WRITEABLE(m, bits) (void)0
#define vm_page_xbusy_claim(m)
#endif
#if BYTE_ORDER == BIG_ENDIAN

4
sys/vm/vm_swapout.c
View File

@ -540,6 +540,7 @@ vm_thread_swapout(struct thread *td)
if (m == NULL)
panic("vm_thread_swapout: kstack already missing?");
vm_page_dirty(m);
vm_page_xunbusy_unchecked(m);
vm_page_unwire(m, PQ_LAUNDRY);
}
VM_OBJECT_WUNLOCK(ksobj);
@ -564,7 +565,6 @@ vm_thread_swapin(struct thread *td, int oom_alloc)
for (i = 0; i < pages;) {
vm_page_assert_xbusied(ma[i]);
if (vm_page_all_valid(ma[i])) {
vm_page_xunbusy(ma[i]);
i++;
continue;
}
@ -581,8 +581,6 @@ vm_thread_swapin(struct thread *td, int oom_alloc)
KASSERT(rv == VM_PAGER_OK, ("%s: cannot get kstack for proc %d",
__func__, td->td_proc->p_pid));
vm_object_pip_wakeup(ksobj);
for (j = i; j < i + count; j++)
vm_page_xunbusy(ma[j]);
i += count;
}
pmap_qenter(td->td_kstack, ma, pages);