Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Fix an overflow bug in major GC work computation #10680

Merged
merged 2 commits into from
Oct 6, 2021
Merged

Fix an overflow bug in major GC work computation #10680

Changes from 1 commit
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
da2563f
Fix an overflow bug in major GC work computation
stedolan Oct 5, 2021
6ea5e36
Changes
stedolan Oct 6, 2021
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
16 changes: 10 additions & 6 deletions runtime/major_gc.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -647,6 +647,7 @@ Caml_noinline static intnat do_some_marking

while (1) {
value *scan, *obj_end, *scan_end;
intnat scan_len;

if (pb_enqueued > pb_dequeued + min_pb) {
/* Dequeue from prefetch buffer */
Expand Down Expand Up @@ -700,11 +701,13 @@ Caml_noinline static intnat do_some_marking
obj_end = m.end;
}

scan_end = obj_end;
work -= obj_end - scan;
if (work < 0) {
scan_end += work;
scan_len = obj_end - scan;
if (work < scan_len) {
scan_len = work;
if (scan_len < 0) scan_len = 0;
}
work -= scan_len;
scan_end = scan + scan_len;

for (; scan < scan_end; scan++) {
value v = *scan;
Expand All @@ -716,7 +719,9 @@ Caml_noinline static intnat do_some_marking
slice_pointers ++;
#endif
if (pb_enqueued == pb_dequeued + Pb_size) {
break; /* Prefetch buffer is full */
/* Prefetch buffer is full */
work += scan_end - scan; /* scanning work not done */
break;
}
prefetch_block(v);
pb[(pb_enqueued++) & Pb_mask] = v;
Expand All @@ -732,7 +737,6 @@ Caml_noinline static intnat do_some_marking
/* Didn't finish scanning this object, either because work <= 0,
or the prefetch buffer filled up. Leave the rest on the stack. */
mark_entry m = { scan, obj_end };
work += obj_end - scan;
caml_prefetch(scan+1);
if (stk.count == stk.size) {
*Caml_state->mark_stack = stk;
Expand Down