swiper: iterate full pages

dora-runtime/src/gc.rs

@@ -599,7 +599,7 @@ pub fn fill_region(vm: &VM, start: Address, end: Address) {
             *start.offset(mem::ptr_width_usize()).to_mut_ptr::<usize>() = 0;
             *start.offset(Header::size() as usize).to_mut_ptr::<usize>() = length;
 
-            if cfg!(debug) {
+            if cfg!(debug_assertions) {
                 for idx in 0..length {
                     *start
                         .offset(Header::size() as usize)

dora-runtime/src/gc/swiper.rs

@@ -17,7 +17,7 @@ use crate::gc::swiper::young::YoungGen;
 use crate::gc::tlab;
 use crate::gc::Collector;
 use crate::gc::GcReason;
-use crate::gc::{align_page_up, fill_region, formatted_size, Address, Region, K};
+use crate::gc::{align_page_up, formatted_size, Address, Region, K};
 use crate::mem;
 use crate::object::Obj;
 use crate::os::{self, MemoryPermission, Reservation};
@@ -634,48 +634,8 @@ where
         fct(object, scan, object_size);
         scan = scan.offset(object_size);
     }
-}
-
-const MIN_OBJECTS_TO_SKIP: usize = 4;
-
-pub fn walk_region_and_skip_garbage<F>(vm: &VM, region: Region, mut fct: F)
-where
-    F: FnMut(&mut Obj, Address, usize) -> bool,
-{
-    let mut scan = region.start;
-    let mut garbage_start = Address::null();
-    let mut garbage_objects = 0;
-
-    while scan < region.end {
-        let object = scan.to_mut_obj();
-
-        if object.header().vtblptr().is_null() {
-            scan = scan.add_ptr(1);
-            continue;
-        }
-
-        let object_size = object.size();
-        let marked = fct(object, scan, object_size);
-        scan = scan.offset(object_size);
 
-        if marked {
-            if garbage_objects >= MIN_OBJECTS_TO_SKIP {
-                fill_region(vm, garbage_start, object.address());
-            }
-
-            garbage_objects = 0;
-        } else {
-            if garbage_objects == 0 {
-                garbage_start = object.address();
-            }
-
-            garbage_objects += 1;
-        }
-    }
-
-    if garbage_objects >= MIN_OBJECTS_TO_SKIP {
-        fill_region(vm, garbage_start, region.end);
-    }
+    assert_eq!(scan, region.end);
 }
 
 pub trait CommonOldGen {

dora-runtime/src/gc/swiper/full.rs

@@ -9,7 +9,7 @@ use crate::gc::swiper::crossing::CrossingMap;
 use crate::gc::swiper::large::LargeSpace;
 use crate::gc::swiper::old::{OldGen, OldGenProtected, Page};
 use crate::gc::swiper::young::YoungGen;
-use crate::gc::swiper::{forward_full, walk_region, walk_region_and_skip_garbage};
+use crate::gc::swiper::{forward_full, walk_region};
 use crate::gc::{fill_region, iterate_strong_roots, iterate_weak_roots, marking, Slot};
 use crate::gc::{Address, GcReason, Region};
 use crate::object::Obj;
@@ -194,9 +194,6 @@ impl<'a> FullCollector<'a> {
             if object.header().is_marked_non_atomic() {
                 let fwd = full.allocate(object_size);
                 object.header_mut().set_fwdptr_non_atomic(fwd);
-                true
-            } else {
-                false
             }
         });
 
@@ -362,38 +359,29 @@ impl<'a> FullCollector<'a> {
 
     fn walk_old_and_young_and_skip_garbage<F>(&mut self, mut fct: F)
     where
-        F: FnMut(&mut FullCollector, &mut Obj, Address, usize) -> bool,
+        F: FnMut(&mut FullCollector, &mut Obj, Address, usize),
     {
-        let vm = self.vm;
-
         let pages = self.old_protected.pages.clone();
         let mut last = self.old.total_start();
 
         for page in pages {
             assert_eq!(last, page.start());
-
-            let region = if page.end() == self.old_protected.current_limit {
-                Region::new(page.start(), self.old_protected.top)
-            } else {
-                page.area()
-            };
-
-            walk_region_and_skip_garbage(vm, region, |obj, addr, size| fct(self, obj, addr, size));
-            last = region.end();
+            walk_region(page.area(), |obj, addr, size| {
+                fct(self, obj, addr, size);
+            });
+            last = page.end();
         }
 
-        assert_eq!(self.old_protected.active_region().end(), last);
-
         // This is a bit strange at first: from-space might not be empty,
         // after too many survivors in the minor GC of the young gen.
         let used_region = self.young.from_active();
-        walk_region_and_skip_garbage(vm, used_region, |obj, addr, size| {
-            fct(self, obj, addr, size)
+        walk_region(used_region, |obj, addr, size| {
+            fct(self, obj, addr, size);
         });
 
         let used_region = self.young.to_active();
-        walk_region_and_skip_garbage(vm, used_region, |obj, addr, size| {
-            fct(self, obj, addr, size)
+        walk_region(used_region, |obj, addr, size| {
+            fct(self, obj, addr, size);
         });
     }
 

dora-runtime/src/gc/swiper/old.rs

@@ -100,6 +100,8 @@ impl GenerationAllocator for OldGen {
         let mut protected = self.protected.lock();
 
         if let Some(address) = protected.raw_alloc(size) {
+            fill_region(get_vm(), protected.top, protected.current_limit);
+            self.update_crossing(protected.top, protected.current_limit);
             return Some(address);
         }
 
@@ -122,6 +124,10 @@ impl GenerationAllocator for OldGen {
             let result = protected.raw_alloc(size);
             assert!(result.is_some());
 
+            // Make rest of page iterable.
+            fill_region(get_vm(), protected.top, protected.current_limit);
+            self.update_crossing(protected.top, protected.current_limit);
+
             result
         } else {
             None

dora-runtime/src/gc/swiper/verify.rs

@@ -160,15 +160,8 @@ impl<'a> Verifier<'a> {
 
         for page in pages {
             assert_eq!(last, page.start());
-
-            let region = if page.end() == self.old_protected.current_limit {
-                Region::new(page.start(), self.old_protected.top)
-            } else {
-                page.area()
-            };
-
-            self.verify_objects(region, "old gen");
-            last = region.end();
+            self.verify_objects(page.area(), "old gen");
+            last = page.end();
         }
 
         self.in_old = false;