Author: jeff Date: Wed Feb 19 09:10:11 2020 New Revision: 358098 URL: https://svnweb.freebsd.org/changeset/base/358098
Log: Don't release xbusy on kmem pages. After lockless page lookup we will not be able to guarantee that they can be racquired without blocking. Reviewed by: kib Discussed with: markj Differential Revision: https://reviews.freebsd.org/D23506 Modified: head/sys/vm/vm_glue.c head/sys/vm/vm_kern.c head/sys/vm/vm_page.h head/sys/vm/vm_swapout.c Modified: head/sys/vm/vm_glue.c ============================================================================== --- head/sys/vm/vm_glue.c Wed Feb 19 08:17:27 2020 (r358097) +++ head/sys/vm/vm_glue.c Wed Feb 19 09:10:11 2020 (r358098) @@ -342,10 +342,8 @@ vm_thread_stack_create(struct domainset *ds, vm_object 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 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); } Modified: head/sys/vm/vm_kern.c ============================================================================== --- head/sys/vm/vm_kern.c Wed Feb 19 08:17:27 2020 (r358097) +++ head/sys/vm/vm_kern.c Wed Feb 19 09:10:11 2020 (r358098) @@ -224,7 +224,6 @@ retry: 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 @@ retry: 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 @@ retry: 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_ #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); } Modified: head/sys/vm/vm_page.h ============================================================================== --- head/sys/vm/vm_page.h Wed Feb 19 08:17:27 2020 (r358097) +++ head/sys/vm/vm_page.h Wed Feb 19 09:10:11 2020 (r358098) @@ -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 Modified: head/sys/vm/vm_swapout.c ============================================================================== --- head/sys/vm/vm_swapout.c Wed Feb 19 08:17:27 2020 (r358097) +++ head/sys/vm/vm_swapout.c Wed Feb 19 09:10:11 2020 (r358098) @@ -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); _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
