From: Michael Tremer <michael.tremer@ipfire.org>
Date: Tue, 23 Aug 2022 13:02:50 +0000 (+0000)
Subject: database: Call madvise() to tell the kernel that we will randomly access the data
X-Git-Tag: 0.9.15~14
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e63d76be69e6be4704a9925300f0055148e7a41d;p=location%2Flibloc.git

database: Call madvise() to tell the kernel that we will randomly access the data

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---

diff --git a/src/database.c b/src/database.c
index a76afad..311f4ab 100644
--- a/src/database.c
+++ b/src/database.c
@@ -243,6 +243,9 @@ ERROR:
 	Maps the entire database into memory
 */
 static int loc_database_mmap(struct loc_database* db) {
+	int r;
+
+	// Get file descriptor
 	int fd = fileno(db->f);
 
 	// Determine the length of the database
@@ -264,6 +267,13 @@ static int loc_database_mmap(struct loc_database* db) {
 
 	DEBUG(db->ctx, "Mapped database of %zu byte(s) at %p\n", db->length, db->data);
 
+	// Tell the system that we expect to read data randomly
+	r = madvise(db->data, db->length, MADV_RANDOM);
+	if (r) {
+		ERROR(db->ctx, "madvise() failed: %m\n");
+		return r;
+	}
+
 	return 0;
 }