From: Christian Brauner <christian.brauner@ubuntu.com>
Date: Tue, 2 Oct 2018 14:40:13 +0000 (+0200)
Subject: parse: prefault config file with MAP_POPULATE
X-Git-Tag: lxc-3.1.0~70^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F2667%2Fhead;p=thirdparty%2Flxc.git

parse: prefault config file with MAP_POPULATE

When we call lxc_file_for_each_line_mmap() we will always parse the
whole config file. Prefault it in case it is really long to optimize
performance.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---

diff --git a/src/lxc/parse.c b/src/lxc/parse.c
index fcc174a77..1c0cc9f49 100644
--- a/src/lxc/parse.c
+++ b/src/lxc/parse.c
@@ -88,7 +88,8 @@ int lxc_file_for_each_line_mmap(const char *file, lxc_file_cb callback,
 		return 0;
 	}
 
-	buf = lxc_strmmap(NULL, st.st_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
+	buf = lxc_strmmap(NULL, st.st_size, PROT_READ | PROT_WRITE,
+			  MAP_PRIVATE | MAP_POPULATE, fd, 0);
 	if (buf == MAP_FAILED) {
 		close(fd);
 		return -1;