From 22648d16cc2eda61b4eb1d1543b04f4ce59a0be0 Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Fri, 31 Jul 2020 13:34:02 +0200
Subject: [SERVER] FUSE: Use splice with move for local reads

Greatly improves performance when reading from the local disk cache, and
additionally avoids having everything in the fs cache twice (disk view
and fuse view).
---
 src/server/fuse.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

(limited to 'src')

diff --git a/src/server/fuse.c b/src/server/fuse.c
index 48e3e5e..1496972 100644
--- a/src/server/fuse.c
+++ b/src/server/fuse.c
@@ -319,7 +319,7 @@ static void ll_read( fuse_req_t req, fuse_ino_t ino UNUSED, size_t size, off_t o
 			.fd = -1,
 		};
 	}
-	fuse_reply_data( req, vec, 0 );
+	fuse_reply_data( req, vec, FUSE_BUF_SPLICE_MOVE );
 	free( vec );
 }
 
@@ -517,6 +517,20 @@ static void uplinkCallback(void *data, uint64_t handle UNUSED, uint64_t start UN
 	}
 }
 
+#define DUMP(key,type) logadd( LOG_DEBUG1, "FUSE: " #key ": " type, conn->key )
+void ll_init(void *userdata, struct fuse_conn_info *conn)
+{
+	DUMP( capable, "%u" );
+	DUMP( congestion_threshold, "%u" );
+	DUMP( max_background, "%u" );
+	//DUMP( max_read, "%u" );
+	DUMP( max_readahead, "%u" );
+	DUMP( max_write, "%u" );
+	DUMP( want, "%u" );
+	conn->want |= FUSE_CAP_SPLICE_READ | FUSE_CAP_SPLICE_WRITE | FUSE_CAP_SPLICE_MOVE;
+}
+#undef DUMP
+
 /* map the implemented fuse operations */
 static struct fuse_lowlevel_ops fuseOps = {
 	.lookup = ll_lookup,
@@ -527,7 +541,7 @@ static struct fuse_lowlevel_ops fuseOps = {
 	.release = ll_release,
 	.read = ll_read,
 	.write = ll_write,
-	//.init = ll_init,
+	.init = ll_init,
 	//.destroy = ll_destroy,
 };
 
-- 
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