From 03a7ad9448eacec31c6dca312654453eddadb59d Mon Sep 17 00:00:00 2001 From: John Johansen Date: Wed, 15 Sep 2010 10:28:20 -0700 Subject: UBUNTU: SAUCE: Improve Amazon EBS performance for EC2 OriginalAuthor: Amazona from Ben Howard BugLink: http://bugs.launchpad.net/bugs/634316 The pv-ops kernel suffers from poor performance when using Amazon's Elastic block storage (EBS). This patch from Amazon improves pv-ops kernel performance, and has not exhibited any regressions. Signed-off-by: John Johansen Signed-off-by: Leann Ogasawara --- include/xen/interface/io/blkif.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'include') diff --git a/include/xen/interface/io/blkif.h b/include/xen/interface/io/blkif.h index ee338bfde18..31063bd1b69 100644 --- a/include/xen/interface/io/blkif.h +++ b/include/xen/interface/io/blkif.h @@ -168,6 +168,18 @@ struct blkif_response { DEFINE_RING_TYPES(blkif, struct blkif_request, struct blkif_response); +/* + * Maximum number of pages used for a blkif ring + * max-ring-pages advertised by blkback to blkfront may be lowered at blkback + * mod load time. Load time param set to default. + */ +#define BLKIF_MAX_NUM_RING_PAGES 16 +#define BLKIF_MAX_NUM_RING_PAGES_DFLT 4 +#if BLKIF_MAX_NUM_RING_PAGES < BLKIF_MAX_NUM_RING_PAGES_DFLT +#undef BLKIF_MAX_NUM_RING_PAGES_DFLT +#define BLKIF_MAX_NUM_RING_PAGES_DFLT BLKIF_MAX_NUM_RING_PAGES +#endif + #define VDISK_CDROM 0x1 #define VDISK_REMOVABLE 0x2 #define VDISK_READONLY 0x4 -- cgit v1.2.3