From cf570d0206a7b3b4efb39b16b196b210e863c9f6 Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@igalia.com>
Date: Mon, 16 Sep 2024 10:51:07 +0200
Subject: [PATCH] Don't release shared worklist buffers when less than 256 kB

Fixes https://github.com/wingo/whippet/issues/8.
---
 src/shared-worklist.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/shared-worklist.h b/src/shared-worklist.h
index 6d5ed3315..afefb11e2 100644
--- a/src/shared-worklist.h
+++ b/src/shared-worklist.h
@@ -29,6 +29,8 @@ struct shared_worklist_buf {
 // Max size: 2 GB on 64-bit systems, 1 GB on 32-bit.
 #define shared_worklist_buf_max_log_size ((unsigned) 28)
 
+static const size_t shared_worklist_release_byte_threshold = 256 * 1024;
+
 static int
 shared_worklist_buf_init(struct shared_worklist_buf *buf, unsigned log_size) {
   ASSERT(log_size >= shared_worklist_buf_min_log_size);
@@ -59,8 +61,9 @@ shared_worklist_buf_byte_size(struct shared_worklist_buf *buf) {
 
 static void
 shared_worklist_buf_release(struct shared_worklist_buf *buf) {
-  if (buf->data)
-    madvise(buf->data, shared_worklist_buf_byte_size(buf), MADV_DONTNEED);
+  size_t byte_size = shared_worklist_buf_byte_size(buf);
+  if (buf->data && byte_size >= shared_worklist_release_byte_threshold)
+    madvise(buf->data, byte_size, MADV_DONTNEED);
 }
 
 static void