From d16318ade57a75455f2130c1396d100e351e1ecd Mon Sep 17 00:00:00 2001 From: Petri Latvala Date: Tue, 27 Sep 2016 12:22:12 +0300 Subject: lib: Do two writes to /proc/sys/vm/drop_caches again The drop_caches sysctl has a max value of 4, so writing 7 to it just fails. Avoid the earlier two-writes problem by opening the fd twice. v2: Don't lseek(), open() twice. (Chris) Signed-off-by: Petri Latvala --- lib/intel_os.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'lib/intel_os.c') diff --git a/lib/intel_os.c b/lib/intel_os.c index b9f970df..0f9af634 100644 --- a/lib/intel_os.c +++ b/lib/intel_os.c @@ -295,15 +295,27 @@ void intel_purge_vm_caches(void) { int fd; + fd = open("/proc/sys/vm/drop_caches", O_WRONLY); + if (fd >= 0) { + /* BIT(2): Be quiet. Cannot be combined with other operations, + * the sysctl has a max value of 4. + */ + igt_ignore_warn(write(fd, "4\n", 2)); + close(fd); + } + + /* Reset write position back to start. Do as a seperate write to keep + * the stages segregated and avoid failure from the squelching stopping + * the purge. + */ fd = open("/proc/sys/vm/drop_caches", O_WRONLY); if (fd < 0) return; /* BIT(0): Drop page cache * BIT(1): Drop slab cache - * BIT(2): Be quiet in future */ - igt_ignore_warn(write(fd, "7\n", 2)); + igt_ignore_warn(write(fd, "3\n", 2)); close(fd); } -- cgit v1.2.3