From 83d0c3846d6b7ed73e813db296eac3e42004dd07 Mon Sep 17 00:00:00 2001 From: Alexander Motin Date: Wed, 22 May 2019 18:43:48 +0000 Subject: [PATCH] Allocate buffers smaller then ABD chunk size as linear. This allows to reduce memory waste by letting UMA to put multiple small buffers into one memory page slab. The page sharing means that UMA may not be able to free memory page when some of buffers are freed, but alternatively memory used by that buffer would just be wasted from the beginning. This change follows alike change in ZoL, but unlike Linux (according to my understanding of it from comments) FreeBSD never shares slabs bigger then one memory page, so this should be even less invasive then there. MFC after: 2 weeks Sponsored by: iXsystems, Inc. --- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/abd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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 f6e4a92dd4c2..3730d53f5eb4 100644 --- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/abd.c +++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/abd.c @@ -290,7 +290,7 @@ abd_free_struct(abd_t *abd) abd_t * abd_alloc(size_t size, boolean_t is_metadata) { - if (!zfs_abd_scatter_enabled) + if (!zfs_abd_scatter_enabled || size <= zfs_abd_chunk_size) return (abd_alloc_linear(size, is_metadata)); VERIFY3U(size, <=, SPA_MAXBLOCKSIZE);