diff options
Diffstat (limited to 'usr/src/uts/common/sys/swap.h')
| -rw-r--r-- | usr/src/uts/common/sys/swap.h | 56 |
1 files changed, 23 insertions, 33 deletions
diff --git a/usr/src/uts/common/sys/swap.h b/usr/src/uts/common/sys/swap.h index 9bba487ec1..bfe5fe3349 100644 --- a/usr/src/uts/common/sys/swap.h +++ b/usr/src/uts/common/sys/swap.h @@ -2,9 +2,8 @@ * CDDL HEADER START * * The contents of this file are subject to the terms of the - * Common Development and Distribution License, Version 1.0 only - * (the "License"). You may not use this file except in compliance - * with the License. + * Common Development and Distribution License (the "License"). + * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. @@ -20,8 +19,7 @@ * CDDL HEADER END */ /* - * Copyright 2005 Sun Microsystems, Inc. All rights reserved. - * Use is subject to license terms. + * Copyright (c) 1987, 2010, Oracle and/or its affiliates. All rights reserved. */ /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */ @@ -40,8 +38,6 @@ #ifndef _SYS_SWAP_H #define _SYS_SWAP_H -#pragma ident "%Z%%M% %I% %E% SMI" - #include <sys/isa_defs.h> #include <sys/feature_tests.h> #include <vm/anon.h> @@ -159,23 +155,17 @@ struct swapinfo { /* * Stuff to convert an anon slot pointer to a page name. * Because the address of the slot (ap) is a unique identifier, we - * use it to generate a unique (vp,off), as shown below. - * - * |<-- 11 bits -->|<------32 - 11 --------->| - * vp index bits off bits + * use it to generate a unique (vp,off), as shown in the comment for + * swap_alloc(). * * The off bits are shifted PAGESHIFT to directly form a page aligned * offset; the vp index bits map 1-1 to a vnode. * - * Note: if we go to 64 bit offsets, we could use all the bits as the - * unique offset and just have one vnode. */ -#define AN_OFFSHIFT 11 /* vnum # bits */ -#define AN_VPSHIFT 21 /* 32 - 11 */ -#define AN_VPSIZEMASK 0x7FF /* vp index mask */ -#define MAX_SWAP_VNODES 2048 /* 1 << AN_OFFSHIFT */ -#define AN_CACHE_ALIGN 16 /* anon address aligned */ - /* 16 bytes */ +#define MAX_SWAP_VNODES_LOG2 11 /* log2(MAX_SWAP_VNODES) */ +#define MAX_SWAP_VNODES (1U << MAX_SWAP_VNODES_LOG2) /* max # swap vnodes */ +#define AN_VPMASK (MAX_SWAP_VNODES - 1) /* vp index mask */ +#define AN_VPSHIFT MAX_SWAP_VNODES_LOG2 /* * Convert from an anon slot to associated vnode and offset. */ @@ -189,24 +179,24 @@ struct swapinfo { /* * Get a vnode name for an anon slot. * The vnum, offset are derived from anon struct address which is - * 16 bytes aligned. To get swap offset the anon address is shifted - * by additional 11 bits which yields 32K aligned swap offset - * (11 bits plus 4 bits alignment). - * The vnum (vnode index) is created from bits 31-21. - * The 64 bit swap offset is created from bits 63-32 and 20-4. - * The 32 bit offset is created from bits 20-4. + * 16 bytes aligned. anon structs may be kmem_cache_alloc'd concurrently by + * multiple threads and come from a small range of addresses (same slab), in + * which case high order AP bits do not vary much, so choose vnum from low + * order bits which vary the most. Different threads will thus get different + * vnums and vnodes, which avoids vph_mutex_contention on the subsequent + * page_hashin(). * - * +-----------...----------+--------+-----------------------+----+ - * | swap offset | vnum | swap offset |0000| - * +-----------...----------+--------+-----------------------+----+ - * 63 32 31 21 20 4 3 0 + * +-----------...-------------------+-----------------------+----+ + * | swap offset | vnum |0000| + * +-----------...-------------------+-----------------------+----+ + * 63 15 14 4 3 0 */ #define swap_alloc(AP) \ { \ - (AP)->an_vp = swapfs_getvp(((uintptr_t)(AP) >> AN_VPSHIFT) \ - & AN_VPSIZEMASK); \ - (AP)->an_off = (anoff_t)(((uintptr_t)(AP) & ~(uintptr_t)0xFFFFFFFF) \ - | (((uintptr_t)(AP) << AN_OFFSHIFT) & (uintptr_t)0xFFFFFFFF)); \ + (AP)->an_vp = swapfs_getvp(((uintptr_t)(AP) >> AN_CACHE_ALIGN_LOG2) \ + & AN_VPMASK); \ + (AP)->an_off = (anoff_t)((((uintptr_t)(AP)) >> \ + AN_VPSHIFT + AN_CACHE_ALIGN_LOG2) << PAGESHIFT); \ } /* |