fuse: make the number of max background requests and congestion threshold tunable
The practical values for these limits depend on the design of the
filesystem server so let userspace set them at initialization time.
Signed-off-by: Csaba Henk <csaba@gluster.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index f91ccc4..9aa6f46 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -32,6 +32,12 @@
#define FUSE_DEFAULT_BLKSIZE 512
+/** Maximum number of outstanding background requests */
+#define FUSE_DEFAULT_MAX_BACKGROUND 12
+
+/** Congestion starts at 75% of maximum */
+#define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
+
struct fuse_mount_data {
int fd;
unsigned rootmode;
@@ -517,6 +523,8 @@
INIT_LIST_HEAD(&fc->bg_queue);
INIT_LIST_HEAD(&fc->entry);
atomic_set(&fc->num_waiting, 0);
+ fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
+ fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
fc->khctr = 0;
fc->polled_files = RB_ROOT;
fc->reqctr = 0;
@@ -736,6 +744,12 @@
else {
unsigned long ra_pages;
+ if (arg->minor >= 13) {
+ if (arg->max_background)
+ fc->max_background = arg->max_background;
+ if (arg->congestion_threshold)
+ fc->congestion_threshold = arg->congestion_threshold;
+ }
if (arg->minor >= 6) {
ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
if (arg->flags & FUSE_ASYNC_READ)