From 5e13986cc0b3c1da0a7f7e6e26659769280e890b Mon Sep 17 00:00:00 2001
From: tarsin <yuanqingxiang233@163.com>
Date: Fri, 2 Dec 2022 17:33:43 +0800
Subject: [PATCH] Prefault archive mapping page tables for small files

---
 app/src/main/cpp/archive.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/app/src/main/cpp/archive.c b/app/src/main/cpp/archive.c
index 416a0f550..6d31359df 100644
--- a/app/src/main/cpp/archive.c
+++ b/app/src/main/cpp/archive.c
@@ -52,6 +52,8 @@ static char *passwd = NULL;
 static void *archiveAddr = NULL;
 static size_t archiveSize = 0;
 
+#define POPULATE_THRESHOLD (512 * 1024 * 1024) // 512 MiB
+
 const char supportExt[9][6] = {
         "jpeg",
         "jpg",
@@ -199,7 +201,10 @@ Java_com_hippo_UriArchiveAccessor_openArchive(JNIEnv *env, jobject thiz, jint fd
     EH_UNUSED(env);
     EH_UNUSED(thiz);
     archive_ctx *ctx = NULL;
-    archiveAddr = mmap64(0, size, PROT_READ, MAP_PRIVATE, fd, 0);
+    int mmap_flags = MAP_PRIVATE;
+    if (size <= POPULATE_THRESHOLD)
+        mmap_flags |= MAP_POPULATE;
+    archiveAddr = mmap64(0, size, PROT_READ, mmap_flags, fd, 0);
     if (archiveAddr == MAP_FAILED) {
         LOGE("%s%s", "mmap64 failed with error ", strerror(errno));
         return 0;