From: Matthew Dillon <dillon@apollo.backplane.com>
Date: Mon, 21 Feb 2011 02:26:17 +0000 (-0800)
Subject: HAMMER - Fix long stalls when writing out core files
X-Git-Tag: v2.10.0~267^2~39
X-Git-Url: http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/a117fbeb5f7e15c128fb94d038d5382d8d03483c

HAMMER - Fix long stalls when writing out core files

* Fix a long-stall case (hmrwww) due to a broken pipelining algorithm when
  using large write()s to write out large files.
---

diff --git a/sys/vfs/hammer/hammer.h b/sys/vfs/hammer/hammer.h
index f85e6c5..a0bb98e 100644
--- a/sys/vfs/hammer/hammer.h
+++ b/sys/vfs/hammer/hammer.h
@@ -437,7 +437,7 @@ typedef struct hammer_inode *hammer_inode_t;
 #define HAMMER_INODE_DELETED	0x0080	/* inode delete (backend) */
 #define HAMMER_INODE_DELONDISK	0x0100	/* delete synchronized to disk */
 #define HAMMER_INODE_RO		0x0200	/* read-only (because of as-of) */
-#define HAMMER_INODE_UNUSED0400	0x0400
+#define HAMMER_INODE_RECSW	0x0400	/* waiting on data record flush */
 #define HAMMER_INODE_DONDISK	0x0800	/* data records may be on disk */
 #define HAMMER_INODE_BUFS	0x1000	/* dirty high level bps present */
 #define HAMMER_INODE_REFLUSH	0x2000	/* flush on dependancy / reflush */
diff --git a/sys/vfs/hammer/hammer_object.c b/sys/vfs/hammer/hammer_object.c
index 8786cc8..56b4a97 100644
--- a/sys/vfs/hammer/hammer_object.c
+++ b/sys/vfs/hammer/hammer_object.c
@@ -447,8 +447,11 @@ hammer_rel_mem_record(struct hammer_record *record)
 
 				if (RB_EMPTY(&record->ip->rec_tree))
 					hammer_test_inode(record->ip);
-				if (ip->rsv_recs == hammer_limit_inode_recs - 1)
+				if ((ip->flags & HAMMER_INODE_RECSW) &&
+				    ip->rsv_recs <= hammer_limit_inode_recs/2) {
+					ip->flags &= ~HAMMER_INODE_RECSW;
 					wakeup(&ip->rsv_recs);
+				}
 			}
 
 			/*
diff --git a/sys/vfs/hammer/hammer_vfsops.c b/sys/vfs/hammer/hammer_vfsops.c
index fd1e7d1..d83d900 100644
--- a/sys/vfs/hammer/hammer_vfsops.c
+++ b/sys/vfs/hammer/hammer_vfsops.c
@@ -104,7 +104,7 @@ int hammer_count_io_locked;
 int hammer_limit_dirtybufspace;		/* per-mount */
 int hammer_limit_running_io;		/* per-mount */
 int hammer_limit_recs;			/* as a whole XXX */
-int hammer_limit_inode_recs = 1024;	/* per inode */
+int hammer_limit_inode_recs = 2048;	/* per inode */
 int hammer_limit_reclaim;
 int hammer_live_dedup_cache_size = DEDUP_CACHE_SIZE;
 int hammer_limit_redo = 4096 * 1024;	/* per inode */
diff --git a/sys/vfs/hammer/hammer_vnops.c b/sys/vfs/hammer/hammer_vnops.c
index 21e6106..fa1d68b 100644
--- a/sys/vfs/hammer/hammer_vnops.c
+++ b/sys/vfs/hammer/hammer_vnops.c
@@ -581,15 +581,18 @@ hammer_vop_write(struct vop_write_args *ap)
 		 * Control the number of pending records associated with
 		 * this inode.  If too many have accumulated start a
 		 * flush.  Try to maintain a pipeline with the flusher.
+		 *
+		 * NOTE: It is possible for other sources to grow the
+		 *	 records but not necessarily issue another flush,
+		 *	 so use a timeout and ensure that a re-flush occurs.
 		 */
 		if (ip->rsv_recs >= hammer_limit_inode_recs) {
 			hammer_flush_inode(ip, HAMMER_FLUSH_SIGNAL);
-		}
-		if (ip->rsv_recs >= hammer_limit_inode_recs * 2) {
-			while (ip->rsv_recs >= hammer_limit_inode_recs) {
+			while (ip->rsv_recs >= hammer_limit_inode_recs * 2) {
+				ip->flags |= HAMMER_INODE_RECSW;
 				tsleep(&ip->rsv_recs, 0, "hmrwww", hz);
+				hammer_flush_inode(ip, HAMMER_FLUSH_SIGNAL);
 			}
-			hammer_flush_inode(ip, HAMMER_FLUSH_SIGNAL);
 		}
 
 #if 0