From 52d97ef7c7841c679cd8086a678fa40666d6a59f Mon Sep 17 00:00:00 2001 From: avg Date: Wed, 20 Sep 2017 08:36:31 +0000 Subject: [PATCH] add vfs_zfs.abd_chunk_size tunable It is reported that the default value of 4KB results in a substantial memory use overhead (at least, on some configurations). Using 1KB seems to reduce the overhead significantly. PR: 222377 Reported by: Sean Chittenden MFC after: 1 week --- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/abd.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/abd.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/abd.c index 94e5a220854c..2cd87c2b87bf 100644 --- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/abd.c +++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/abd.c @@ -150,6 +150,13 @@ boolean_t zfs_abd_scatter_enabled = B_TRUE; */ size_t zfs_abd_chunk_size = 4096; +#if defined(__FreeBSD__) && defined(_KERNEL) +SYSCTL_DECL(_vfs_zfs); + +SYSCTL_ULONG(_vfs_zfs, OID_AUTO, abd_chunk_size, CTLFLAG_RDTUN, + &zfs_abd_chunk_size, 0, "The size of the chunks ABD allocates"); +#endif + #ifdef _KERNEL extern vmem_t *zio_alloc_arena; #endif