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Date:      Fri, 28 Jun 2013 01:29:35 -0700
From:      Adrian Chadd <adrian@freebsd.org>
To:        Jeff Roberson <jeff@freebsd.org>
Cc:        svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org
Subject:   Re: svn commit: r252330 - in head/sys: conf geom kern sys vm
Message-ID:  <CAJ-VmokRJrdKbZnNEDRfWahsWL-WNReHozV=_t3sw=6OrbcKNQ@mail.gmail.com>
In-Reply-To: <201306280351.r5S3pLAm098083@svn.freebsd.org>
References:  <201306280351.r5S3pLAm098083@svn.freebsd.org>

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Hi,

Do we really need another allocator / resource manager just for this?




Adrian

On 27 June 2013 20:51, Jeff Roberson <jeff@freebsd.org> wrote:
> Author: jeff
> Date: Fri Jun 28 03:51:20 2013
> New Revision: 252330
> URL: http://svnweb.freebsd.org/changeset/base/252330
>
> Log:
>    - Add a general purpose resource allocator, vmem, from NetBSD.  It was
>      originally inspired by the Solaris vmem detailed in the proceedings
>      of usenix 2001.  The NetBSD version was heavily refactored for bugs
>      and simplicity.
>    - Use this resource allocator to allocate the buffer and transient maps.
>      Buffer cache defrags are reduced by 25% when used by filesystems with
>      mixed block sizes.  Ultimately this may permit dynamic buffer cache
>      sizing on low KVA machines.
>
>   Discussed with:       alc, kib, attilio
>   Tested by:    pho
>   Sponsored by: EMC / Isilon Storage Division
>
> Added:
>   head/sys/kern/subr_vmem.c   (contents, props changed)
>   head/sys/sys/vmem.h   (contents, props changed)
> Modified:
>   head/sys/conf/files
>   head/sys/geom/geom_io.c
>   head/sys/kern/vfs_bio.c
>   head/sys/sys/malloc.h
>   head/sys/vm/vm.h
>   head/sys/vm/vm_init.c
>   head/sys/vm/vm_kern.c
>   head/sys/vm/vm_kern.h
>   head/sys/vm/vm_object.c
>   head/sys/vm/vm_pager.c
>   head/sys/vm/vm_pager.h
>
> Modified: head/sys/conf/files
> ==============================================================================
> --- head/sys/conf/files Fri Jun 28 03:41:23 2013        (r252329)
> +++ head/sys/conf/files Fri Jun 28 03:51:20 2013        (r252330)
> @@ -2797,6 +2797,7 @@ kern/subr_trap.c          standard
>  kern/subr_turnstile.c          standard
>  kern/subr_uio.c                        standard
>  kern/subr_unit.c               standard
> +kern/subr_vmem.c               standard
>  kern/subr_witness.c            optional witness
>  kern/sys_capability.c          standard
>  kern/sys_generic.c             standard
>
> Modified: head/sys/geom/geom_io.c
> ==============================================================================
> --- head/sys/geom/geom_io.c     Fri Jun 28 03:41:23 2013        (r252329)
> +++ head/sys/geom/geom_io.c     Fri Jun 28 03:51:20 2013        (r252330)
> @@ -49,6 +49,7 @@ __FBSDID("$FreeBSD$");
>  #include <sys/proc.h>
>  #include <sys/stack.h>
>  #include <sys/sysctl.h>
> +#include <sys/vmem.h>
>
>  #include <sys/errno.h>
>  #include <geom/geom.h>
> @@ -626,7 +627,6 @@ g_io_transient_map_bio(struct bio *bp)
>         vm_offset_t addr;
>         long size;
>         u_int retried;
> -       int rv;
>
>         KASSERT(unmapped_buf_allowed, ("unmapped disabled"));
>
> @@ -636,10 +636,7 @@ g_io_transient_map_bio(struct bio *bp)
>         retried = 0;
>         atomic_add_long(&transient_maps, 1);
>  retry:
> -       vm_map_lock(bio_transient_map);
> -       if (vm_map_findspace(bio_transient_map, vm_map_min(bio_transient_map),
> -           size, &addr)) {
> -               vm_map_unlock(bio_transient_map);
> +       if (vmem_alloc(transient_arena, size, M_BESTFIT | M_NOWAIT, &addr)) {
>                 if (transient_map_retries != 0 &&
>                     retried >= transient_map_retries) {
>                         g_io_deliver(bp, EDEADLK/* XXXKIB */);
> @@ -651,7 +648,7 @@ retry:
>                         /*
>                          * Naive attempt to quisce the I/O to get more
>                          * in-flight requests completed and defragment
> -                        * the bio_transient_map.
> +                        * the transient_arena.
>                          */
>                         CTR3(KTR_GEOM, "g_down retrymap bp %p provider %s r %d",
>                             bp, bp->bio_to->name, retried);
> @@ -661,12 +658,6 @@ retry:
>                         goto retry;
>                 }
>         }
> -       rv = vm_map_insert(bio_transient_map, NULL, 0, addr, addr + size,
> -           VM_PROT_RW, VM_PROT_RW, MAP_NOFAULT);
> -       KASSERT(rv == KERN_SUCCESS,
> -           ("vm_map_insert(bio_transient_map) rv %d %jx %lx",
> -           rv, (uintmax_t)addr, size));
> -       vm_map_unlock(bio_transient_map);
>         atomic_add_int(&inflight_transient_maps, 1);
>         pmap_qenter((vm_offset_t)addr, bp->bio_ma, OFF_TO_IDX(size));
>         bp->bio_data = (caddr_t)addr + bp->bio_ma_offset;
>
> Added: head/sys/kern/subr_vmem.c
> ==============================================================================
> --- /dev/null   00:00:00 1970   (empty, because file is newly added)
> +++ head/sys/kern/subr_vmem.c   Fri Jun 28 03:51:20 2013        (r252330)
> @@ -0,0 +1,1372 @@
> +/*-
> + * Copyright (c)2006,2007,2008,2009 YAMAMOTO Takashi,
> + * Copyright (c) 2013 EMC Corp.
> + * All rights reserved.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions
> + * are met:
> + * 1. Redistributions of source code must retain the above copyright
> + *    notice, this list of conditions and the following disclaimer.
> + * 2. Redistributions in binary form must reproduce the above copyright
> + *    notice, this list of conditions and the following disclaimer in the
> + *    documentation and/or other materials provided with the distribution.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
> + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> + * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
> + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
> + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
> + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
> + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
> + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> + * SUCH DAMAGE.
> + */
> +
> +/*
> + * From:
> + *     $NetBSD: vmem_impl.h,v 1.2 2013/01/29 21:26:24 para Exp $
> + *     $NetBSD: subr_vmem.c,v 1.83 2013/03/06 11:20:10 yamt Exp $
> + */
> +
> +/*
> + * reference:
> + * -   Magazines and Vmem: Extending the Slab Allocator
> + *     to Many CPUs and Arbitrary Resources
> + *     http://www.usenix.org/event/usenix01/bonwick.html
> + */
> +
> +#include <sys/cdefs.h>
> +__FBSDID("$FreeBSD$");
> +
> +#include "opt_ddb.h"
> +
> +#include <sys/param.h>
> +#include <sys/systm.h>
> +#include <sys/kernel.h>
> +#include <sys/queue.h>
> +#include <sys/callout.h>
> +#include <sys/hash.h>
> +#include <sys/lock.h>
> +#include <sys/malloc.h>
> +#include <sys/mutex.h>
> +#include <sys/smp.h>
> +#include <sys/condvar.h>
> +#include <sys/taskqueue.h>
> +#include <sys/vmem.h>
> +
> +#include <vm/uma.h>
> +#include <vm/vm.h>
> +#include <vm/pmap.h>
> +#include <vm/vm_map.h>
> +#include <vm/vm_kern.h>
> +#include <vm/vm_extern.h>
> +#include <vm/vm_param.h>
> +#include <vm/vm_pageout.h>
> +
> +#define        VMEM_MAXORDER           (sizeof(vmem_size_t) * NBBY)
> +
> +#define        VMEM_HASHSIZE_MIN       16
> +#define        VMEM_HASHSIZE_MAX       131072
> +
> +#define        VMEM_QCACHE_IDX_MAX     16
> +
> +#define        VMEM_FITMASK    (M_BESTFIT | M_FIRSTFIT)
> +
> +#define        VMEM_FLAGS                                              \
> +    (M_NOWAIT | M_WAITOK | M_USE_RESERVE | M_NOVM | M_BESTFIT | M_FIRSTFIT)
> +
> +#define        BT_FLAGS        (M_NOWAIT | M_WAITOK | M_USE_RESERVE | M_NOVM)
> +
> +#define        QC_NAME_MAX     16
> +
> +/*
> + * Data structures private to vmem.
> + */
> +MALLOC_DEFINE(M_VMEM, "vmem", "vmem internal structures");
> +
> +typedef struct vmem_btag bt_t;
> +
> +TAILQ_HEAD(vmem_seglist, vmem_btag);
> +LIST_HEAD(vmem_freelist, vmem_btag);
> +LIST_HEAD(vmem_hashlist, vmem_btag);
> +
> +struct qcache {
> +       uma_zone_t      qc_cache;
> +       vmem_t          *qc_vmem;
> +       vmem_size_t     qc_size;
> +       char            qc_name[QC_NAME_MAX];
> +};
> +typedef struct qcache qcache_t;
> +#define        QC_POOL_TO_QCACHE(pool) ((qcache_t *)(pool->pr_qcache))
> +
> +#define        VMEM_NAME_MAX   16
> +
> +/* vmem arena */
> +struct vmem {
> +       struct mtx_padalign     vm_lock;
> +       struct cv               vm_cv;
> +       char                    vm_name[VMEM_NAME_MAX+1];
> +       LIST_ENTRY(vmem)        vm_alllist;
> +       struct vmem_hashlist    vm_hash0[VMEM_HASHSIZE_MIN];
> +       struct vmem_freelist    vm_freelist[VMEM_MAXORDER];
> +       struct vmem_seglist     vm_seglist;
> +       struct vmem_hashlist    *vm_hashlist;
> +       vmem_size_t             vm_hashsize;
> +
> +       /* Constant after init */
> +       vmem_size_t             vm_qcache_max;
> +       vmem_size_t             vm_quantum_mask;
> +       vmem_size_t             vm_import_quantum;
> +       int                     vm_quantum_shift;
> +
> +       /* Written on alloc/free */
> +       LIST_HEAD(, vmem_btag)  vm_freetags;
> +       int                     vm_nfreetags;
> +       int                     vm_nbusytag;
> +       vmem_size_t             vm_inuse;
> +       vmem_size_t             vm_size;
> +
> +       /* Used on import. */
> +       vmem_import_t           *vm_importfn;
> +       vmem_release_t          *vm_releasefn;
> +       void                    *vm_arg;
> +
> +       /* Space exhaustion callback. */
> +       vmem_reclaim_t          *vm_reclaimfn;
> +
> +       /* quantum cache */
> +       qcache_t                vm_qcache[VMEM_QCACHE_IDX_MAX];
> +};
> +
> +/* boundary tag */
> +struct vmem_btag {
> +       TAILQ_ENTRY(vmem_btag) bt_seglist;
> +       union {
> +               LIST_ENTRY(vmem_btag) u_freelist; /* BT_TYPE_FREE */
> +               LIST_ENTRY(vmem_btag) u_hashlist; /* BT_TYPE_BUSY */
> +       } bt_u;
> +#define        bt_hashlist     bt_u.u_hashlist
> +#define        bt_freelist     bt_u.u_freelist
> +       vmem_addr_t     bt_start;
> +       vmem_size_t     bt_size;
> +       int             bt_type;
> +};
> +
> +#define        BT_TYPE_SPAN            1       /* Allocated from importfn */
> +#define        BT_TYPE_SPAN_STATIC     2       /* vmem_add() or create. */
> +#define        BT_TYPE_FREE            3       /* Available space. */
> +#define        BT_TYPE_BUSY            4       /* Used space. */
> +#define        BT_ISSPAN_P(bt) ((bt)->bt_type <= BT_TYPE_SPAN_STATIC)
> +
> +#define        BT_END(bt)      ((bt)->bt_start + (bt)->bt_size - 1)
> +
> +#if defined(DIAGNOSTIC)
> +static void vmem_check(vmem_t *);
> +#endif
> +
> +static struct callout  vmem_periodic_ch;
> +static int             vmem_periodic_interval;
> +static struct task     vmem_periodic_wk;
> +
> +static struct mtx_padalign vmem_list_lock;
> +static LIST_HEAD(, vmem) vmem_list = LIST_HEAD_INITIALIZER(vmem_list);
> +
> +/* ---- misc */
> +#define        VMEM_CONDVAR_INIT(vm, wchan)    cv_init(&vm->vm_cv, wchan)
> +#define        VMEM_CONDVAR_DESTROY(vm)        cv_destroy(&vm->vm_cv)
> +#define        VMEM_CONDVAR_WAIT(vm)           cv_wait(&vm->vm_cv, &vm->vm_lock)
> +#define        VMEM_CONDVAR_BROADCAST(vm)      cv_broadcast(&vm->vm_cv)
> +
> +
> +#define        VMEM_LOCK(vm)           mtx_lock(&vm->vm_lock)
> +#define        VMEM_TRYLOCK(vm)        mtx_trylock(&vm->vm_lock)
> +#define        VMEM_UNLOCK(vm)         mtx_unlock(&vm->vm_lock)
> +#define        VMEM_LOCK_INIT(vm, name) mtx_init(&vm->vm_lock, (name), NULL, MTX_DEF)
> +#define        VMEM_LOCK_DESTROY(vm)   mtx_destroy(&vm->vm_lock)
> +#define        VMEM_ASSERT_LOCKED(vm)  mtx_assert(&vm->vm_lock, MA_OWNED);
> +
> +#define        VMEM_ALIGNUP(addr, align)       (-(-(addr) & -(align)))
> +
> +#define        VMEM_CROSS_P(addr1, addr2, boundary) \
> +       ((((addr1) ^ (addr2)) & -(boundary)) != 0)
> +
> +#define        ORDER2SIZE(order)       ((vmem_size_t)1 << (order))
> +#define        SIZE2ORDER(size)        ((int)flsl(size) - 1)
> +
> +/*
> + * Maximum number of boundary tags that may be required to satisfy an
> + * allocation.  Two may be required to import.  Another two may be
> + * required to clip edges.
> + */
> +#define        BT_MAXALLOC     4
> +
> +/*
> + * Max free limits the number of locally cached boundary tags.  We
> + * just want to avoid hitting the zone allocator for every call.
> + */
> +#define BT_MAXFREE     (BT_MAXALLOC * 8)
> +
> +/* Allocator for boundary tags. */
> +static uma_zone_t vmem_bt_zone;
> +
> +/* boot time arena storage. */
> +static struct vmem buffer_arena_storage;
> +static struct vmem transient_arena_storage;
> +vmem_t *buffer_arena = &buffer_arena_storage;
> +vmem_t *transient_arena = &transient_arena_storage;
> +
> +/*
> + * Fill the vmem's boundary tag cache.  We guarantee that boundary tag
> + * allocation will not fail once bt_fill() passes.  To do so we cache
> + * at least the maximum possible tag allocations in the arena.
> + */
> +static int
> +bt_fill(vmem_t *vm, int flags)
> +{
> +       bt_t *bt;
> +
> +       VMEM_ASSERT_LOCKED(vm);
> +
> +       /*
> +        * Loop until we meet the reserve.  To minimize the lock shuffle
> +        * and prevent simultaneous fills we first try a NOWAIT regardless
> +        * of the caller's flags.  Specify M_NOVM so we don't recurse while
> +        * holding a vmem lock.
> +        */
> +       while (vm->vm_nfreetags < BT_MAXALLOC) {
> +               bt = uma_zalloc(vmem_bt_zone,
> +                   (flags & M_USE_RESERVE) | M_NOWAIT | M_NOVM);
> +               if (bt == NULL) {
> +                       VMEM_UNLOCK(vm);
> +                       bt = uma_zalloc(vmem_bt_zone, flags);
> +                       VMEM_LOCK(vm);
> +                       if (bt == NULL && (flags & M_NOWAIT) != 0)
> +                               break;
> +               }
> +               LIST_INSERT_HEAD(&vm->vm_freetags, bt, bt_freelist);
> +               vm->vm_nfreetags++;
> +       }
> +
> +       if (vm->vm_nfreetags < BT_MAXALLOC)
> +               return ENOMEM;
> +
> +       return 0;
> +}
> +
> +/*
> + * Pop a tag off of the freetag stack.
> + */
> +static bt_t *
> +bt_alloc(vmem_t *vm)
> +{
> +       bt_t *bt;
> +
> +       VMEM_ASSERT_LOCKED(vm);
> +       bt = LIST_FIRST(&vm->vm_freetags);
> +       MPASS(bt != NULL);
> +       LIST_REMOVE(bt, bt_freelist);
> +       vm->vm_nfreetags--;
> +
> +       return bt;
> +}
> +
> +/*
> + * Trim the per-vmem free list.  Returns with the lock released to
> + * avoid allocator recursions.
> + */
> +static void
> +bt_freetrim(vmem_t *vm, int freelimit)
> +{
> +       LIST_HEAD(, vmem_btag) freetags;
> +       bt_t *bt;
> +
> +       LIST_INIT(&freetags);
> +       VMEM_ASSERT_LOCKED(vm);
> +       while (vm->vm_nfreetags > freelimit) {
> +               bt = LIST_FIRST(&vm->vm_freetags);
> +               LIST_REMOVE(bt, bt_freelist);
> +               vm->vm_nfreetags--;
> +               LIST_INSERT_HEAD(&freetags, bt, bt_freelist);
> +       }
> +       VMEM_UNLOCK(vm);
> +       while ((bt = LIST_FIRST(&freetags)) != NULL) {
> +               LIST_REMOVE(bt, bt_freelist);
> +               uma_zfree(vmem_bt_zone, bt);
> +       }
> +}
> +
> +static inline void
> +bt_free(vmem_t *vm, bt_t *bt)
> +{
> +
> +       VMEM_ASSERT_LOCKED(vm);
> +       MPASS(LIST_FIRST(&vm->vm_freetags) != bt);
> +       LIST_INSERT_HEAD(&vm->vm_freetags, bt, bt_freelist);
> +       vm->vm_nfreetags++;
> +}
> +
> +/*
> + * freelist[0] ... [1, 1]
> + * freelist[1] ... [2, 3]
> + * freelist[2] ... [4, 7]
> + * freelist[3] ... [8, 15]
> + *  :
> + * freelist[n] ... [(1 << n), (1 << (n + 1)) - 1]
> + *  :
> + */
> +
> +static struct vmem_freelist *
> +bt_freehead_tofree(vmem_t *vm, vmem_size_t size)
> +{
> +       const vmem_size_t qsize = size >> vm->vm_quantum_shift;
> +       const int idx = SIZE2ORDER(qsize);
> +
> +       MPASS(size != 0 && qsize != 0);
> +       MPASS((size & vm->vm_quantum_mask) == 0);
> +       MPASS(idx >= 0);
> +       MPASS(idx < VMEM_MAXORDER);
> +
> +       return &vm->vm_freelist[idx];
> +}
> +
> +/*
> + * bt_freehead_toalloc: return the freelist for the given size and allocation
> + * strategy.
> + *
> + * For M_FIRSTFIT, return the list in which any blocks are large enough
> + * for the requested size.  otherwise, return the list which can have blocks
> + * large enough for the requested size.
> + */
> +static struct vmem_freelist *
> +bt_freehead_toalloc(vmem_t *vm, vmem_size_t size, int strat)
> +{
> +       const vmem_size_t qsize = size >> vm->vm_quantum_shift;
> +       int idx = SIZE2ORDER(qsize);
> +
> +       MPASS(size != 0 && qsize != 0);
> +       MPASS((size & vm->vm_quantum_mask) == 0);
> +
> +       if (strat == M_FIRSTFIT && ORDER2SIZE(idx) != qsize) {
> +               idx++;
> +               /* check too large request? */
> +       }
> +       MPASS(idx >= 0);
> +       MPASS(idx < VMEM_MAXORDER);
> +
> +       return &vm->vm_freelist[idx];
> +}
> +
> +/* ---- boundary tag hash */
> +
> +static struct vmem_hashlist *
> +bt_hashhead(vmem_t *vm, vmem_addr_t addr)
> +{
> +       struct vmem_hashlist *list;
> +       unsigned int hash;
> +
> +       hash = hash32_buf(&addr, sizeof(addr), 0);
> +       list = &vm->vm_hashlist[hash % vm->vm_hashsize];
> +
> +       return list;
> +}
> +
> +static bt_t *
> +bt_lookupbusy(vmem_t *vm, vmem_addr_t addr)
> +{
> +       struct vmem_hashlist *list;
> +       bt_t *bt;
> +
> +       VMEM_ASSERT_LOCKED(vm);
> +       list = bt_hashhead(vm, addr);
> +       LIST_FOREACH(bt, list, bt_hashlist) {
> +               if (bt->bt_start == addr) {
> +                       break;
> +               }
> +       }
> +
> +       return bt;
> +}
> +
> +static void
> +bt_rembusy(vmem_t *vm, bt_t *bt)
> +{
> +
> +       VMEM_ASSERT_LOCKED(vm);
> +       MPASS(vm->vm_nbusytag > 0);
> +       vm->vm_inuse -= bt->bt_size;
> +       vm->vm_nbusytag--;
> +       LIST_REMOVE(bt, bt_hashlist);
> +}
> +
> +static void
> +bt_insbusy(vmem_t *vm, bt_t *bt)
> +{
> +       struct vmem_hashlist *list;
> +
> +       VMEM_ASSERT_LOCKED(vm);
> +       MPASS(bt->bt_type == BT_TYPE_BUSY);
> +
> +       list = bt_hashhead(vm, bt->bt_start);
> +       LIST_INSERT_HEAD(list, bt, bt_hashlist);
> +       vm->vm_nbusytag++;
> +       vm->vm_inuse += bt->bt_size;
> +}
> +
> +/* ---- boundary tag list */
> +
> +static void
> +bt_remseg(vmem_t *vm, bt_t *bt)
> +{
> +
> +       TAILQ_REMOVE(&vm->vm_seglist, bt, bt_seglist);
> +       bt_free(vm, bt);
> +}
> +
> +static void
> +bt_insseg(vmem_t *vm, bt_t *bt, bt_t *prev)
> +{
> +
> +       TAILQ_INSERT_AFTER(&vm->vm_seglist, prev, bt, bt_seglist);
> +}
> +
> +static void
> +bt_insseg_tail(vmem_t *vm, bt_t *bt)
> +{
> +
> +       TAILQ_INSERT_TAIL(&vm->vm_seglist, bt, bt_seglist);
> +}
> +
> +static void
> +bt_remfree(vmem_t *vm, bt_t *bt)
> +{
> +
> +       MPASS(bt->bt_type == BT_TYPE_FREE);
> +
> +       LIST_REMOVE(bt, bt_freelist);
> +}
> +
> +static void
> +bt_insfree(vmem_t *vm, bt_t *bt)
> +{
> +       struct vmem_freelist *list;
> +
> +       list = bt_freehead_tofree(vm, bt->bt_size);
> +       LIST_INSERT_HEAD(list, bt, bt_freelist);
> +}
> +
> +/* ---- vmem internal functions */
> +
> +/*
> + * Import from the arena into the quantum cache in UMA.
> + */
> +static int
> +qc_import(void *arg, void **store, int cnt, int flags)
> +{
> +       qcache_t *qc;
> +       vmem_addr_t addr;
> +       int i;
> +
> +       qc = arg;
> +       flags |= M_BESTFIT;
> +       for (i = 0; i < cnt; i++) {
> +               if (vmem_xalloc(qc->qc_vmem, qc->qc_size, 0, 0, 0,
> +                   VMEM_ADDR_MIN, VMEM_ADDR_MAX, flags, &addr) != 0)
> +                       break;
> +               store[i] = (void *)addr;
> +               /* Only guarantee one allocation. */
> +               flags &= ~M_WAITOK;
> +               flags |= M_NOWAIT;
> +       }
> +       return i;
> +}
> +
> +/*
> + * Release memory from the UMA cache to the arena.
> + */
> +static void
> +qc_release(void *arg, void **store, int cnt)
> +{
> +       qcache_t *qc;
> +       int i;
> +
> +       qc = arg;
> +       for (i = 0; i < cnt; i++)
> +               vmem_xfree(qc->qc_vmem, (vmem_addr_t)store[i], qc->qc_size);
> +}
> +
> +static void
> +qc_init(vmem_t *vm, vmem_size_t qcache_max)
> +{
> +       qcache_t *qc;
> +       vmem_size_t size;
> +       int qcache_idx_max;
> +       int i;
> +
> +       MPASS((qcache_max & vm->vm_quantum_mask) == 0);
> +       qcache_idx_max = MIN(qcache_max >> vm->vm_quantum_shift,
> +           VMEM_QCACHE_IDX_MAX);
> +       vm->vm_qcache_max = qcache_idx_max << vm->vm_quantum_shift;
> +       for (i = 0; i < qcache_idx_max; i++) {
> +               qc = &vm->vm_qcache[i];
> +               size = (i + 1) << vm->vm_quantum_shift;
> +               snprintf(qc->qc_name, sizeof(qc->qc_name), "%s-%zu",
> +                   vm->vm_name, size);
> +               qc->qc_vmem = vm;
> +               qc->qc_size = size;
> +               qc->qc_cache = uma_zcache_create(qc->qc_name, size,
> +                   NULL, NULL, NULL, NULL, qc_import, qc_release, qc,
> +                   UMA_ZONE_VM);
> +               MPASS(qc->qc_cache);
> +       }
> +}
> +
> +static void
> +qc_destroy(vmem_t *vm)
> +{
> +       int qcache_idx_max;
> +       int i;
> +
> +       qcache_idx_max = vm->vm_qcache_max >> vm->vm_quantum_shift;
> +       for (i = 0; i < qcache_idx_max; i++)
> +               uma_zdestroy(vm->vm_qcache[i].qc_cache);
> +}
> +
> +static void
> +qc_drain(vmem_t *vm)
> +{
> +       int qcache_idx_max;
> +       int i;
> +
> +       qcache_idx_max = vm->vm_qcache_max >> vm->vm_quantum_shift;
> +       for (i = 0; i < qcache_idx_max; i++)
> +               zone_drain(vm->vm_qcache[i].qc_cache);
> +}
> +
> +void
> +vmem_startup(void)
> +{
> +
> +       mtx_init(&vmem_list_lock, "vmem list lock", NULL, MTX_DEF);
> +       vmem_bt_zone = uma_zcreate("vmem btag",
> +           sizeof(struct vmem_btag), NULL, NULL, NULL, NULL,
> +           UMA_ALIGN_PTR, UMA_ZONE_VM);
> +}
> +
> +/* ---- rehash */
> +
> +static int
> +vmem_rehash(vmem_t *vm, vmem_size_t newhashsize)
> +{
> +       bt_t *bt;
> +       int i;
> +       struct vmem_hashlist *newhashlist;
> +       struct vmem_hashlist *oldhashlist;
> +       vmem_size_t oldhashsize;
> +
> +       MPASS(newhashsize > 0);
> +
> +       newhashlist = malloc(sizeof(struct vmem_hashlist) * newhashsize,
> +           M_VMEM, M_NOWAIT);
> +       if (newhashlist == NULL)
> +               return ENOMEM;
> +       for (i = 0; i < newhashsize; i++) {
> +               LIST_INIT(&newhashlist[i]);
> +       }
> +
> +       VMEM_LOCK(vm);
> +       oldhashlist = vm->vm_hashlist;
> +       oldhashsize = vm->vm_hashsize;
> +       vm->vm_hashlist = newhashlist;
> +       vm->vm_hashsize = newhashsize;
> +       if (oldhashlist == NULL) {
> +               VMEM_UNLOCK(vm);
> +               return 0;
> +       }
> +       for (i = 0; i < oldhashsize; i++) {
> +               while ((bt = LIST_FIRST(&oldhashlist[i])) != NULL) {
> +                       bt_rembusy(vm, bt);
> +                       bt_insbusy(vm, bt);
> +               }
> +       }
> +       VMEM_UNLOCK(vm);
> +
> +       if (oldhashlist != vm->vm_hash0) {
> +               free(oldhashlist, M_VMEM);
> +       }
> +
> +       return 0;
> +}
> +
> +static void
> +vmem_periodic_kick(void *dummy)
> +{
> +
> +       taskqueue_enqueue(taskqueue_thread, &vmem_periodic_wk);
> +}
> +
> +static void
> +vmem_periodic(void *unused, int pending)
> +{
> +       vmem_t *vm;
> +       vmem_size_t desired;
> +       vmem_size_t current;
> +
> +       mtx_lock(&vmem_list_lock);
> +       LIST_FOREACH(vm, &vmem_list, vm_alllist) {
> +#ifdef DIAGNOSTIC
> +               /* Convenient time to verify vmem state. */
> +               VMEM_LOCK(vm);
> +               vmem_check(vm);
> +               VMEM_UNLOCK(vm);
> +#endif
> +               desired = 1 << flsl(vm->vm_nbusytag);
> +               desired = MIN(MAX(desired, VMEM_HASHSIZE_MIN),
> +                   VMEM_HASHSIZE_MAX);
> +               current = vm->vm_hashsize;
> +
> +               /* Grow in powers of two.  Shrink less aggressively. */
> +               if (desired >= current * 2 || desired * 4 <= current)
> +                       vmem_rehash(vm, desired);
> +       }
> +       mtx_unlock(&vmem_list_lock);
> +
> +       callout_reset(&vmem_periodic_ch, vmem_periodic_interval,
> +           vmem_periodic_kick, NULL);
> +}
> +
> +static void
> +vmem_start_callout(void *unused)
> +{
> +
> +       TASK_INIT(&vmem_periodic_wk, 0, vmem_periodic, NULL);
> +       vmem_periodic_interval = hz * 10;
> +       callout_init(&vmem_periodic_ch, CALLOUT_MPSAFE);
> +       callout_reset(&vmem_periodic_ch, vmem_periodic_interval,
> +           vmem_periodic_kick, NULL);
> +}
> +SYSINIT(vfs, SI_SUB_CONFIGURE, SI_ORDER_ANY, vmem_start_callout, NULL);
> +
> +static void
> +vmem_add1(vmem_t *vm, vmem_addr_t addr, vmem_size_t size, int flags, int type)
> +{
> +       bt_t *btspan;
> +       bt_t *btfree;
> +
> +       MPASS(type == BT_TYPE_SPAN || type == BT_TYPE_SPAN_STATIC);
> +
> +       btspan = bt_alloc(vm);
> +       btspan->bt_type = type;
> +       btspan->bt_start = addr;
> +       btspan->bt_size = size;
> +
> +       btfree = bt_alloc(vm);
> +       btfree->bt_type = BT_TYPE_FREE;
> +       btfree->bt_start = addr;
> +       btfree->bt_size = size;
> +
> +       bt_insseg_tail(vm, btspan);
> +       bt_insseg(vm, btfree, btspan);
> +       bt_insfree(vm, btfree);
> +       vm->vm_size += size;
> +}
> +
> +static void
> +vmem_destroy1(vmem_t *vm)
> +{
> +       bt_t *bt;
> +
> +       /*
> +        * Drain per-cpu quantum caches.
> +        */
> +       qc_destroy(vm);
> +
> +       /*
> +        * The vmem should now only contain empty segments.
> +        */
> +       VMEM_LOCK(vm);
> +       MPASS(vm->vm_nbusytag == 0);
> +
> +       while ((bt = TAILQ_FIRST(&vm->vm_seglist)) != NULL)
> +               bt_remseg(vm, bt);
> +
> +       if (vm->vm_hashlist != NULL && vm->vm_hashlist != vm->vm_hash0)
> +               free(vm->vm_hashlist, M_VMEM);
> +
> +       bt_freetrim(vm, 0);
> +
> +       VMEM_CONDVAR_DESTROY(vm);
> +       VMEM_LOCK_DESTROY(vm);
> +       free(vm, M_VMEM);
> +}
> +
> +static int
> +vmem_import(vmem_t *vm, vmem_size_t size, int flags)
> +{
> +       vmem_addr_t addr;
> +       int error;
> +
> +       if (vm->vm_importfn == NULL)
> +               return EINVAL;
> +
> +       size = roundup(size, vm->vm_import_quantum);
> +
> +       /*
> +        * Hide MAXALLOC tags so we're guaranteed to be able to add this
> +        * span and the tag we want to allocate from it.
> +        */
> +       MPASS(vm->vm_nfreetags >= BT_MAXALLOC);
> +       vm->vm_nfreetags -= BT_MAXALLOC;
> +       VMEM_UNLOCK(vm);
> +       error = (vm->vm_importfn)(vm->vm_arg, size, flags, &addr);
> +       VMEM_LOCK(vm);
> +       vm->vm_nfreetags += BT_MAXALLOC;
> +       if (error)
> +               return ENOMEM;
> +
> +       vmem_add1(vm, addr, size, flags, BT_TYPE_SPAN);
> +
> +       return 0;
> +}
> +
> +/*
> + * vmem_fit: check if a bt can satisfy the given restrictions.
> + *
> + * it's a caller's responsibility to ensure the region is big enough
> + * before calling us.
> + */
> +static int
> +vmem_fit(const bt_t *bt, vmem_size_t size, vmem_size_t align,
> +    vmem_size_t phase, vmem_size_t nocross, vmem_addr_t minaddr,
> +    vmem_addr_t maxaddr, vmem_addr_t *addrp)
> +{
> +       vmem_addr_t start;
> +       vmem_addr_t end;
> +
> +       MPASS(size > 0);
> +       MPASS(bt->bt_size >= size); /* caller's responsibility */
> +
> +       /*
> +        * XXX assumption: vmem_addr_t and vmem_size_t are
> +        * unsigned integer of the same size.
> +        */
> +
> +       start = bt->bt_start;
> +       if (start < minaddr) {
> +               start = minaddr;
> +       }
> +       end = BT_END(bt);
> +       if (end > maxaddr)
> +               end = maxaddr;
> +       if (start > end)
> +               return (ENOMEM);
> +
> +       start = VMEM_ALIGNUP(start - phase, align) + phase;
> +       if (start < bt->bt_start)
> +               start += align;
> +       if (VMEM_CROSS_P(start, start + size - 1, nocross)) {
> +               MPASS(align < nocross);
> +               start = VMEM_ALIGNUP(start - phase, nocross) + phase;
> +       }
> +       if (start <= end && end - start >= size - 1) {
> +               MPASS((start & (align - 1)) == phase);
> +               MPASS(!VMEM_CROSS_P(start, start + size - 1, nocross));
> +               MPASS(minaddr <= start);
> +               MPASS(maxaddr == 0 || start + size - 1 <= maxaddr);
> +               MPASS(bt->bt_start <= start);
> +               MPASS(BT_END(bt) - start >= size - 1);
> +               *addrp = start;
> +
> +               return (0);
> +       }
> +       return (ENOMEM);
> +}
> +
> +/*
> + * vmem_clip:  Trim the boundary tag edges to the requested start and size.
> + */
> +static void
> +vmem_clip(vmem_t *vm, bt_t *bt, vmem_addr_t start, vmem_size_t size)
> +{
> +       bt_t *btnew;
> +       bt_t *btprev;
> +
> +       VMEM_ASSERT_LOCKED(vm);
> +       MPASS(bt->bt_type == BT_TYPE_FREE);
> +       MPASS(bt->bt_size >= size);
> +       bt_remfree(vm, bt);
> +       if (bt->bt_start != start) {
> +               btprev = bt_alloc(vm);
> +               btprev->bt_type = BT_TYPE_FREE;
> +               btprev->bt_start = bt->bt_start;
> +               btprev->bt_size = start - bt->bt_start;
> +               bt->bt_start = start;
> +               bt->bt_size -= btprev->bt_size;
> +               bt_insfree(vm, btprev);
> +               bt_insseg(vm, btprev,
> +                   TAILQ_PREV(bt, vmem_seglist, bt_seglist));
> +       }
> +       MPASS(bt->bt_start == start);
> +       if (bt->bt_size != size && bt->bt_size - size > vm->vm_quantum_mask) {
> +               /* split */
> +               btnew = bt_alloc(vm);
> +               btnew->bt_type = BT_TYPE_BUSY;
> +               btnew->bt_start = bt->bt_start;
> +               btnew->bt_size = size;
> +               bt->bt_start = bt->bt_start + size;
> +               bt->bt_size -= size;
> +               bt_insfree(vm, bt);
> +               bt_insseg(vm, btnew,
> +                   TAILQ_PREV(bt, vmem_seglist, bt_seglist));
> +               bt_insbusy(vm, btnew);
> +               bt = btnew;
> +       } else {
> +               bt->bt_type = BT_TYPE_BUSY;
> +               bt_insbusy(vm, bt);
> +       }
> +       MPASS(bt->bt_size >= size);
> +       bt->bt_type = BT_TYPE_BUSY;
> +}
> +
> +/* ---- vmem API */
> +
> +void
> +vmem_set_import(vmem_t *vm, vmem_import_t *importfn,
> +     vmem_release_t *releasefn, void *arg, vmem_size_t import_quantum)
> +{
> +
> +       VMEM_LOCK(vm);
> +       vm->vm_importfn = importfn;
> +       vm->vm_releasefn = releasefn;
> +       vm->vm_arg = arg;
> +       vm->vm_import_quantum = import_quantum;
> +       VMEM_UNLOCK(vm);
> +}
> +
> +void
> +vmem_set_reclaim(vmem_t *vm, vmem_reclaim_t *reclaimfn)
> +{
> +
> +       VMEM_LOCK(vm);
> +       vm->vm_reclaimfn = reclaimfn;
> +       VMEM_UNLOCK(vm);
> +}
> +
> +/*
> + * vmem_init: Initializes vmem arena.
> + */
> +vmem_t *
> +vmem_init(vmem_t *vm, const char *name, vmem_addr_t base, vmem_size_t size,
> +    vmem_size_t quantum, vmem_size_t qcache_max, int flags)
> +{
> +       int i;
> +
> +       MPASS(quantum > 0);
> +
> +       bzero(vm, sizeof(*vm));
> +
> +       VMEM_CONDVAR_INIT(vm, name);
> +       VMEM_LOCK_INIT(vm, name);
> +       vm->vm_nfreetags = 0;
> +       LIST_INIT(&vm->vm_freetags);
> +       strlcpy(vm->vm_name, name, sizeof(vm->vm_name));
> +       vm->vm_quantum_mask = quantum - 1;
> +       vm->vm_quantum_shift = SIZE2ORDER(quantum);
> +       MPASS(ORDER2SIZE(vm->vm_quantum_shift) == quantum);
> +       vm->vm_nbusytag = 0;
> +       vm->vm_size = 0;
> +       vm->vm_inuse = 0;
> +       qc_init(vm, qcache_max);
> +
> +       TAILQ_INIT(&vm->vm_seglist);
> +       for (i = 0; i < VMEM_MAXORDER; i++) {
> +               LIST_INIT(&vm->vm_freelist[i]);
> +       }
> +       memset(&vm->vm_hash0, 0, sizeof(vm->vm_hash0));
> +       vm->vm_hashsize = VMEM_HASHSIZE_MIN;
> +       vm->vm_hashlist = vm->vm_hash0;
> +
> +       if (size != 0) {
> +               if (vmem_add(vm, base, size, flags) != 0) {
> +                       vmem_destroy1(vm);
> +                       return NULL;
> +               }
> +       }
> +
> +       mtx_lock(&vmem_list_lock);
> +       LIST_INSERT_HEAD(&vmem_list, vm, vm_alllist);
> +       mtx_unlock(&vmem_list_lock);
> +
> +       return vm;
> +}
> +
> +/*
> + * vmem_create: create an arena.
> + */
> +vmem_t *
> +vmem_create(const char *name, vmem_addr_t base, vmem_size_t size,
> +    vmem_size_t quantum, vmem_size_t qcache_max, int flags)
> +{
> +
> +       vmem_t *vm;
> +
> +       vm = malloc(sizeof(*vm), M_VMEM, flags & (M_WAITOK|M_NOWAIT));
> +       if (vm == NULL)
> +               return (NULL);
> +       if (vmem_init(vm, name, base, size, quantum, qcache_max,
> +           flags) == NULL) {
> +               free(vm, M_VMEM);
> +               return (NULL);
> +       }
> +       return (vm);
> +}
> +
> +void
> +vmem_destroy(vmem_t *vm)
> +{
> +
> +       mtx_lock(&vmem_list_lock);
> +       LIST_REMOVE(vm, vm_alllist);
> +       mtx_unlock(&vmem_list_lock);
> +
> +       vmem_destroy1(vm);
> +}
>
> *** DIFF OUTPUT TRUNCATED AT 1000 LINES ***



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