[Cluster-devel] [GFS2 PATCH 3/3] GFS2: If we use up our block reservation, request more next time

[Bob Peterson <rpeterso@redhat.com>]

If we run out of blocks for a given multi-block allocation, we obviously
did not reserve enough. We should reserve more blocks for the next
reservation to reduce fragmentation. This patch increases the size hint
for reservations when they run out.
---
 fs/gfs2/rgrp.c | 3 +++
 fs/gfs2/rgrp.h | 1 +
 2 files changed, 4 insertions(+)

diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index f4e4a0c..9150207 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -2251,6 +2251,9 @@ static void gfs2_adjust_reservation(struct gfs2_inode *ip,
 			trace_gfs2_rs(rs, TRACE_RS_CLAIM);
 			if (rs->rs_free && !ret)
 				goto out;
+			/* We used up our block reservation, so we should
+			   reserve more blocks next time. */
+			atomic_add(RGRP_RSRV_ADDBLKS, &rs->rs_sizehint);
 		}
 		__rs_deltree(rs);
 	}
diff --git a/fs/gfs2/rgrp.h b/fs/gfs2/rgrp.h
index 5d8f085..b104f4a 100644
--- a/fs/gfs2/rgrp.h
+++ b/fs/gfs2/rgrp.h
@@ -20,6 +20,7 @@
  */
 #define RGRP_RSRV_MINBYTES 8
 #define RGRP_RSRV_MINBLKS ((u32)(RGRP_RSRV_MINBYTES * GFS2_NBBY))
+#define RGRP_RSRV_ADDBLKS 64
 
 struct gfs2_rgrpd;
 struct gfs2_sbd;
-- 
1.9.3