Konstantin Belousov <kostikbel_at_gmail.com> w rote on
Date: Sat, 22 Nov 2025 20:41:27 UTC :

> On Sat, Nov 22, 2025 at 10:19:38PM +0200, Konstantin Belousov wrote:
> > Please in addition to the patch, enable debug.vm_check_pg_zero.
> 
> And use the following patch (one more hunk for vm_object_page_remove()):
> 
> diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
> index 6b09552c5fee..76808b5ad7f1 100644
> --- a/sys/vm/vm_map.c
> +++ b/sys/vm/vm_map.c
> @@ -1743,6 +1743,27 @@ vm_map_insert1(vm_map_t map, vm_object_t object, 
> vm_ooffset_t offset,
>           (vm_size_t)(prev_entry->end - prev_entry->start),
>           (vm_size_t)(end - prev_entry->end), cred != NULL &&
>           (protoeflags & MAP_ENTRY_NEEDS_COPY) == 0)) {
> +             vm_object_t obj = prev_entry->object.vm_object;
> +             if (obj != NULL) {
> +                     struct pctrie_iter pages;
> +                     vm_page_t p;
> +
> +                     vm_page_iter_init(&pages, obj);
> +                     p = vm_radix_iter_lookup_ge(&pages,
> +                         OFF_TO_IDX(prev_entry->offset +
> +                         prev_entry->end - prev_entry->start));
> +                     if (p != NULL) {
> +                             KASSERT(p->pindex >= 
> OFF_TO_IDX(prev_entry->offset +
> +                                 prev_entry->end - prev_entry->start +
> +                                 end - start),
> +                                 ("FOUND page %p pindex %#jx "
> +                                 "e %#jx %#jx %#jx %#jx",
> +                                 p, p->pindex, (uintmax_t)prev_entry->offset,
> +                                 (uintmax_t)prev_entry->end,
> +                                 (uintmax_t)prev_entry->start,
> +                                 (uintmax_t)(end - start)));
> +                     }
> +             }
>               /*
>                * We were able to extend the object.  Determine if we
>                * can extend the previous map entry to include the
> diff --git a/sys/vm/vm_object.c b/sys/vm/vm_object.c
> index 5b4517d2bf0c..e87047f9a380 100644
> --- a/sys/vm/vm_object.c
> +++ b/sys/vm/vm_object.c
> @@ -1988,7 +1988,7 @@ vm_object_page_remove(vm_object_t object, vm_pindex_t 
> start, vm_pindex_t end,
>           (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED,
>           ("vm_object_page_remove: illegal options for object %p", object));
>       if (object->resident_page_count == 0)
> -             return;
> +             goto remove_pager;
>       vm_object_pip_add(object, 1);
>       vm_page_iter_limit_init(&pages, object, end);
>  again:
> @@ -2061,6 +2061,7 @@ vm_object_page_remove(vm_object_t object, vm_pindex_t 
> start, vm_pindex_t end,
>       }
>       vm_object_pip_wakeup(object);
>  
> +remove_pager:
>       vm_pager_freespace(object, start, (end == 0 ? object->size : end) -
>           start);
>  }
> @@ -2189,13 +2190,19 @@ vm_object_coalesce(vm_object_t prev_object, 
> vm_ooffset_t prev_offset,
>       next_size >>= PAGE_SHIFT;
>       next_pindex = OFF_TO_IDX(prev_offset) + prev_size;
>  
> -     if (prev_object->ref_count > 1 &&
> -         prev_object->size != next_pindex &&
> +     if (prev_object->ref_count > 1 ||
> +         prev_object->size != next_pindex ||
>           (prev_object->flags & OBJ_ONEMAPPING) == 0) {
>               VM_OBJECT_WUNLOCK(prev_object);
>               return (FALSE);
>       }
>  
> +     KASSERT(next_pindex + next_size > prev_object->size,
> +         ("vm_object_coalesce: "
> +         "obj %p next_pindex %#jx next_size %#jx obj_size %#jx",
> +         prev_object, (uintmax_t)next_pindex, (uintmax_t)next_size,
> +         (uintmax_t)prev_object->size));
> +
>       /*
>        * Account for the charge.
>        */
> @@ -2222,26 +2229,13 @@ vm_object_coalesce(vm_object_t prev_object, 
> vm_ooffset_t prev_offset,
>        * Remove any pages that may still be in the object from a previous
>        * deallocation.
>        */
> -     if (next_pindex < prev_object->size) {
> -             vm_object_page_remove(prev_object, next_pindex, next_pindex +
> -                 next_size, 0);
> -#if 0
> -             if (prev_object->cred != NULL) {
> -                     KASSERT(prev_object->charge >=
> -                         ptoa(prev_object->size - next_pindex),
> -                         ("object %p overcharged 1 %jx %jx", prev_object,
> -                             (uintmax_t)next_pindex, (uintmax_t)next_size));
> -                     prev_object->charge -= ptoa(prev_object->size -
> -                         next_pindex);
> -             }
> -#endif
> -     }
> +     vm_object_page_remove(prev_object, next_pindex, next_pindex +
> +         next_size, 0);
>  
>       /*
>        * Extend the object if necessary.
>        */
> -     if (next_pindex + next_size > prev_object->size)
> -             prev_object->size = next_pindex + next_size;
> +     prev_object->size = next_pindex + next_size;
>  
>       VM_OBJECT_WUNLOCK(prev_object);
>       return (TRUE);

This completed the lib/clang/libllvm /and lib/clang/libclang/
build activity from prior partial runs. So I started
buildworld over after doing the "rm -fr". It has completed
past the :

/usr/obj/usr/src/i386.i386/lib/clang/

part of the buildworld and is continuing.

So far so good.


Is 15.0 going to hold off for the final form of this? Get
an EN later?

===
Mark Millard
marklmi at yahoo.com


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