From: Miklos Szeredi <mszeredi@xxxxxxx>
Set the read and write congestion state if the request queue is close
to blocking, and clear it when it's not.
This prevents unnecessary blocking in readahead and writeback.
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
---
Index: linux/fs/fuse/dev.c
===================================================================
--- linux.orig/fs/fuse/dev.c 2007-02-27 14:40:55.000000000 +0100
+++ linux/fs/fuse/dev.c 2007-02-27 14:41:09.000000000 +0100
@@ -224,6 +224,10 @@ static void request_end(struct fuse_conn
fc->blocked = 0;
wake_up_all(&fc->blocked_waitq);
}
+ if (fc->num_background == FUSE_CONGESTION_THRESHOLD) {
+ clear_bdi_congested(&fc->bdi, READ);
+ clear_bdi_congested(&fc->bdi, WRITE);
+ }
fc->num_background--;
}
spin_unlock(&fc->lock);
@@ -378,6 +382,10 @@ static void request_send_nowait(struct f
fc->num_background++;
if (fc->num_background == FUSE_MAX_BACKGROUND)
fc->blocked = 1;
+ if (fc->num_background == FUSE_CONGESTION_THRESHOLD) {
+ set_bdi_congested(&fc->bdi, READ);
+ set_bdi_congested(&fc->bdi, WRITE);
+ }
queue_request(fc, req);
spin_unlock(&fc->lock);
Index: linux/fs/fuse/fuse_i.h
===================================================================
--- linux.orig/fs/fuse/fuse_i.h 2007-02-27 14:40:55.000000000 +0100
+++ linux/fs/fuse/fuse_i.h 2007-02-27 14:41:09.000000000 +0100
@@ -20,7 +20,10 @@
#define FUSE_MAX_PAGES_PER_REQ 32
/** Maximum number of outstanding background requests */
-#define FUSE_MAX_BACKGROUND 10
+#define FUSE_MAX_BACKGROUND 12
+
+/** Congestion starts at 75% of maximum */
+#define FUSE_CONGESTION_THRESHOLD (FUSE_MAX_BACKGROUND * 75 / 100)
/** It could be as large as PATH_MAX, but would that have any uses? */
#define FUSE_NAME_MAX 1024
--
-
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