common/vm/seg_kmem.c

	seg_kmem.c revision e291592ab12a560fc73b0610963bb3fe66aab341
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * 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.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 1998, 2010, Oracle and/or its affiliates. All rights reserved.
 */

#include <sys/types.h>
#include <sys/t_lock.h>
#include <sys/param.h>
#include <sys/sysmacros.h>
#include <sys/tuneable.h>
#include <sys/systm.h>
#include <sys/vm.h>
#include <sys/kmem.h>
#include <sys/vmem.h>
#include <sys/mman.h>
#include <sys/cmn_err.h>
#include <sys/debug.h>
#include <sys/dumphdr.h>
#include <sys/bootconf.h>
#include <sys/lgrp.h>
#include <vm/seg_kmem.h>
#include <vm/hat.h>
#include <vm/page.h>
#include <vm/vm_dep.h>
#include <vm/faultcode.h>
#include <sys/promif.h>
#include <vm/seg_kp.h>
#include <sys/bitmap.h>
#include <sys/mem_cage.h>

#ifdef __sparc
#include <sys/ivintr.h>
#include <sys/panic.h>
#endif

/*
 * seg_kmem is the primary kernel memory segment driver.  It
 * maps the kernel heap [kernelheap, ekernelheap), module text,
 * and all memory which was allocated before the VM was initialized
 * into kas.
 *
 * Pages which belong to seg_kmem are hashed into &kvp vnode at
 * an offset equal to (u_offset_t)virt_addr, and have p_lckcnt >= 1.
 * They must never be paged out since segkmem_fault() is a no-op to
 * prevent recursive faults.
 *
 * Currently, seg_kmem pages are sharelocked (p_sharelock == 1) on
 * __x86 and are unlocked (p_sharelock == 0) on __sparc.  Once __x86
 * supports relocation the #ifdef kludges can be removed.
 *
 * seg_kmem pages may be subject to relocation by page_relocate(),
 * provided that the HAT supports it; if this is so, segkmem_reloc
 * will be set to a nonzero value. All boot time allocated memory as
 * well as static memory is considered off limits to relocation.
 * Pages are "relocatable" if p_state does not have P_NORELOC set, so
 * we request P_NORELOC pages for memory that isn't safe to relocate.
 *
 * The kernel heap is logically divided up into four pieces:
 *
 *   heap32_arena is for allocations that require 32-bit absolute
 *   virtual addresses (e.g. code that uses 32-bit pointers/offsets).
 *
 *   heap_core is for allocations that require 2GB *relative*
 *   offsets; in other words all memory from heap_core is within
 *   2GB of all other memory from the same arena. This is a requirement
 *   of the addressing modes of some processors in supervisor code.
 *
 *   heap_arena is the general heap arena.
 *
 *   static_arena is the static memory arena.  Allocations from it
 *   are not subject to relocation so it is safe to use the memory
 *   physical address as well as the virtual address (e.g. the VA to
 *   PA translations are static).  Caches may import from static_arena;
 *   all other static memory allocations should use static_alloc_arena.
 *
 * On some platforms which have limited virtual address space, seg_kmem
 * may share [kernelheap, ekernelheap) with seg_kp; if this is so,
 * segkp_bitmap is non-NULL, and each bit represents a page of virtual
 * address space which is actually seg_kp mapped.
 */

extern ulong_t *segkp_bitmap;   /* Is set if segkp is from the kernel heap */

char *kernelheap;       /* start of primary kernel heap */
char *ekernelheap;      /* end of primary kernel heap */
struct seg kvseg;       /* primary kernel heap segment */
struct seg kvseg_core;      /* "core" kernel heap segment */
struct seg kzioseg;     /* Segment for zio mappings */
vmem_t *heap_arena;     /* primary kernel heap arena */
vmem_t *heap_core_arena;    /* core kernel heap arena */
char *heap_core_base;       /* start of core kernel heap arena */
char *heap_lp_base;     /* start of kernel large page heap arena */
char *heap_lp_end;      /* end of kernel large page heap arena */
vmem_t *hat_memload_arena;  /* HAT translation data */
struct seg kvseg32;     /* 32-bit kernel heap segment */
vmem_t *heap32_arena;       /* 32-bit kernel heap arena */
vmem_t *heaptext_arena;     /* heaptext arena */
struct as kas;          /* kernel address space */
int segkmem_reloc;      /* enable/disable relocatable segkmem pages */
vmem_t *static_arena;       /* arena for caches to import static memory */
vmem_t *static_alloc_arena; /* arena for allocating static memory */
vmem_t *zio_arena = NULL;   /* arena for allocating zio memory */
vmem_t *zio_alloc_arena = NULL; /* arena for allocating zio memory */

/*
 * seg_kmem driver can map part of the kernel heap with large pages.
 * Currently this functionality is implemented for sparc platforms only.
 *
 * The large page size "segkmem_lpsize" for kernel heap is selected in the
 * platform specific code. It can also be modified via /etc/system file.
 * Setting segkmem_lpsize to PAGESIZE in /etc/system disables usage of large
 * pages for kernel heap. "segkmem_lpshift" is adjusted appropriately to
 * match segkmem_lpsize.
 *
 * At boot time we carve from kernel heap arena a range of virtual addresses
 * that will be used for large page mappings. This range [heap_lp_base,
 * heap_lp_end) is set up as a separate vmem arena - "heap_lp_arena". We also
 * create "kmem_lp_arena" that caches memory already backed up by large
 * pages. kmem_lp_arena imports virtual segments from heap_lp_arena.
 */

size_t  segkmem_lpsize;
static  uint_t  segkmem_lpshift = PAGESHIFT;
int segkmem_lpszc = 0;

size_t  segkmem_kmemlp_quantum = 0x400000;  /* 4MB */
size_t  segkmem_heaplp_quantum;
vmem_t *heap_lp_arena;
static  vmem_t *kmem_lp_arena;
static  vmem_t *segkmem_ppa_arena;
static  segkmem_lpcb_t segkmem_lpcb;

/*
 * We use "segkmem_kmemlp_max" to limit the total amount of physical memory
 * consumed by the large page heap. By default this parameter is set to 1/8 of
 * physmem but can be adjusted through /etc/system either directly or
 * indirectly by setting "segkmem_kmemlp_pcnt" to the percent of physmem
 * we allow for large page heap.
 */
size_t  segkmem_kmemlp_max;
static  uint_t  segkmem_kmemlp_pcnt;

/*
 * Getting large pages for kernel heap could be problematic due to
 * physical memory fragmentation. That's why we allow to preallocate
 * "segkmem_kmemlp_min" bytes at boot time.
 */
static  size_t  segkmem_kmemlp_min;

/*
 * Throttling is used to avoid expensive tries to allocate large pages
 * for kernel heap when a lot of succesive attempts to do so fail.
 */
static  ulong_t segkmem_lpthrottle_max = 0x400000;
static  ulong_t segkmem_lpthrottle_start = 0x40;
static  ulong_t segkmem_use_lpthrottle = 1;

/*
 * Freed pages accumulate on a garbage list until segkmem is ready,
 * at which point we call segkmem_gc() to free it all.
 */
typedef struct segkmem_gc_list {
    struct segkmem_gc_list  *gc_next;
    vmem_t          *gc_arena;
    size_t          gc_size;
} segkmem_gc_list_t;

static segkmem_gc_list_t *segkmem_gc_list;

/*
 * Allocations from the hat_memload arena add VM_MEMLOAD to their
 * vmflags so that segkmem_xalloc() can inform the hat layer that it needs
 * to take steps to prevent infinite recursion.  HAT allocations also
 * must be non-relocatable to prevent recursive page faults.
 */
static void *
hat_memload_alloc(vmem_t *vmp, size_t size, int flags)
{
    flags |= (VM_MEMLOAD | VM_NORELOC);
    return (segkmem_alloc(vmp, size, flags));
}

/*
 * Allocations from static_arena arena (or any other arena that uses
 * segkmem_alloc_permanent()) require non-relocatable (permanently
 * wired) memory pages, since these pages are referenced by physical
 * as well as virtual address.
 */
void *
segkmem_alloc_permanent(vmem_t *vmp, size_t size, int flags)
{
    return (segkmem_alloc(vmp, size, flags | VM_NORELOC));
}

/*
 * Initialize kernel heap boundaries.
 */
void
kernelheap_init(
    void *heap_start,
    void *heap_end,
    char *first_avail,
    void *core_start,
    void *core_end)
{
    uintptr_t textbase;
    size_t core_size;
    size_t heap_size;
    vmem_t *heaptext_parent;
    size_t  heap_lp_size = 0;
#ifdef __sparc
    size_t kmem64_sz = kmem64_aligned_end - kmem64_base;
#endif  /* __sparc */

    kernelheap = heap_start;
    ekernelheap = heap_end;

#ifdef __sparc
    heap_lp_size = (((uintptr_t)heap_end - (uintptr_t)heap_start) / 4);
    /*
     * Bias heap_lp start address by kmem64_sz to reduce collisions
     * in 4M kernel TSB between kmem64 area and heap_lp
     */
    kmem64_sz = P2ROUNDUP(kmem64_sz, MMU_PAGESIZE256M);
    if (kmem64_sz <= heap_lp_size / 2)
        heap_lp_size -= kmem64_sz;
    heap_lp_base = ekernelheap - heap_lp_size;
    heap_lp_end = heap_lp_base + heap_lp_size;
#endif  /* __sparc */

    /*
     * If this platform has a 'core' heap area, then the space for
     * overflow module text should be carved out of the end of that
     * heap.  Otherwise, it gets carved out of the general purpose
     * heap.
     */
    core_size = (uintptr_t)core_end - (uintptr_t)core_start;
    if (core_size > 0) {
        ASSERT(core_size >= HEAPTEXT_SIZE);
        textbase = (uintptr_t)core_end - HEAPTEXT_SIZE;
        core_size -= HEAPTEXT_SIZE;
    }
#ifndef __sparc
    else {
        ekernelheap -= HEAPTEXT_SIZE;
        textbase = (uintptr_t)ekernelheap;
    }
#endif

    heap_size = (uintptr_t)ekernelheap - (uintptr_t)kernelheap;
    heap_arena = vmem_init("heap", kernelheap, heap_size, PAGESIZE,
        segkmem_alloc, segkmem_free);

    if (core_size > 0) {
        heap_core_arena = vmem_create("heap_core", core_start,
            core_size, PAGESIZE, NULL, NULL, NULL, 0, VM_SLEEP);
        heap_core_base = core_start;
    } else {
        heap_core_arena = heap_arena;
        heap_core_base = kernelheap;
    }

    /*
     * reserve space for the large page heap. If large pages for kernel
     * heap is enabled large page heap arean will be created later in the
     * boot sequence in segkmem_heap_lp_init(). Otherwise the allocated
     * range will be returned back to the heap_arena.
     */
    if (heap_lp_size) {
        (void) vmem_xalloc(heap_arena, heap_lp_size, PAGESIZE, 0, 0,
            heap_lp_base, heap_lp_end,
            VM_NOSLEEP | VM_BESTFIT | VM_PANIC);
    }

    /*
     * Remove the already-spoken-for memory range [kernelheap, first_avail).
     */
    (void) vmem_xalloc(heap_arena, first_avail - kernelheap, PAGESIZE,
        0, 0, kernelheap, first_avail, VM_NOSLEEP | VM_BESTFIT | VM_PANIC);

#ifdef __sparc
    heap32_arena = vmem_create("heap32", (void *)SYSBASE32,
        SYSLIMIT32 - SYSBASE32 - HEAPTEXT_SIZE, PAGESIZE, NULL,
        NULL, NULL, 0, VM_SLEEP);
    /*
     * Prom claims the physical and virtual resources used by panicbuf
     * and inter_vec_table. So reserve space for panicbuf, intr_vec_table,
     * reserved interrupt vector data structures from 32-bit heap.
     */
    (void) vmem_xalloc(heap32_arena, PANICBUFSIZE, PAGESIZE, 0, 0,
        panicbuf, panicbuf + PANICBUFSIZE,
        VM_NOSLEEP | VM_BESTFIT | VM_PANIC);

    (void) vmem_xalloc(heap32_arena, IVSIZE, PAGESIZE, 0, 0,
        intr_vec_table, (caddr_t)intr_vec_table + IVSIZE,
        VM_NOSLEEP | VM_BESTFIT | VM_PANIC);

    textbase = SYSLIMIT32 - HEAPTEXT_SIZE;
    heaptext_parent = NULL;
#else   /* __sparc */
    heap32_arena = heap_core_arena;
    heaptext_parent = heap_core_arena;
#endif  /* __sparc */

    heaptext_arena = vmem_create("heaptext", (void *)textbase,
        HEAPTEXT_SIZE, PAGESIZE, NULL, NULL, heaptext_parent, 0, VM_SLEEP);

    /*
     * Create a set of arenas for memory with static translations
     * (e.g. VA -> PA translations cannot change).  Since using
     * kernel pages by physical address implies it isn't safe to
     * walk across page boundaries, the static_arena quantum must
     * be PAGESIZE.  Any kmem caches that require static memory
     * should source from static_arena, while direct allocations
     * should only use static_alloc_arena.
     */
    static_arena = vmem_create("static", NULL, 0, PAGESIZE,
        segkmem_alloc_permanent, segkmem_free, heap_arena, 0, VM_SLEEP);
    static_alloc_arena = vmem_create("static_alloc", NULL, 0,
        sizeof (uint64_t), vmem_alloc, vmem_free, static_arena,
        0, VM_SLEEP);

    /*
     * Create an arena for translation data (ptes, hmes, or hblks).
     * We need an arena for this because hat_memload() is essential
     * to vmem_populate() (see comments in common/os/vmem.c).
     *
     * Note: any kmem cache that allocates from hat_memload_arena
     * must be created as a KMC_NOHASH cache (i.e. no external slab
     * and bufctl structures to allocate) so that slab creation doesn't
     * require anything more than a single vmem_alloc().
     */
    hat_memload_arena = vmem_create("hat_memload", NULL, 0, PAGESIZE,
        hat_memload_alloc, segkmem_free, heap_arena, 0,
        VM_SLEEP | VMC_POPULATOR | VMC_DUMPSAFE);
}

void
boot_mapin(caddr_t addr, size_t size)
{
    caddr_t  eaddr;
    page_t  *pp;
    pfn_t    pfnum;

    if (page_resv(btop(size), KM_NOSLEEP) == 0)
        panic("boot_mapin: page_resv failed");

    for (eaddr = addr + size; addr < eaddr; addr += PAGESIZE) {
        pfnum = va_to_pfn(addr);
        if (pfnum == PFN_INVALID)
            continue;
        if ((pp = page_numtopp_nolock(pfnum)) == NULL)
            panic("boot_mapin(): No pp for pfnum = %lx", pfnum);

        /*
         * must break up any large pages that may have constituent
         * pages being utilized for BOP_ALLOC()'s before calling
         * page_numtopp().The locking code (ie. page_reclaim())
         * can't handle them
         */
        if (pp->p_szc != 0)
            page_boot_demote(pp);

        pp = page_numtopp(pfnum, SE_EXCL);
        if (pp == NULL || PP_ISFREE(pp))
            panic("boot_alloc: pp is NULL or free");

        /*
         * If the cage is on but doesn't yet contain this page,
         * mark it as non-relocatable.
         */
        if (kcage_on && !PP_ISNORELOC(pp)) {
            PP_SETNORELOC(pp);
            PLCNT_XFER_NORELOC(pp);
        }

        (void) page_hashin(pp, &kvp, (u_offset_t)(uintptr_t)addr, NULL);
        pp->p_lckcnt = 1;
#if defined(__x86)
        page_downgrade(pp);
#else
        page_unlock(pp);
#endif
    }
}

/*
 * Get pages from boot and hash them into the kernel's vp.
 * Used after page structs have been allocated, but before segkmem is ready.
 */
void *
boot_alloc(void *inaddr, size_t size, uint_t align)
{
    caddr_t addr = inaddr;

    if (bootops == NULL)
        prom_panic("boot_alloc: attempt to allocate memory after "
            "BOP_GONE");

    size = ptob(btopr(size));
#ifdef __sparc
    if (bop_alloc_chunk(addr, size, align) != (caddr_t)addr)
        panic("boot_alloc: bop_alloc_chunk failed");
#else
    if (BOP_ALLOC(bootops, addr, size, align) != addr)
        panic("boot_alloc: BOP_ALLOC failed");
#endif
    boot_mapin((caddr_t)addr, size);
    return (addr);
}

static void
segkmem_badop()
{
    panic("segkmem_badop");
}

#define SEGKMEM_BADOP(t)    (t(*)())segkmem_badop

/*ARGSUSED*/
static faultcode_t
segkmem_fault(struct hat *hat, struct seg *seg, caddr_t addr, size_t size,
    enum fault_type type, enum seg_rw rw)
{
    pgcnt_t npages;
    spgcnt_t pg;
    page_t *pp;
    struct vnode *vp = seg->s_data;

    ASSERT(RW_READ_HELD(&seg->s_as->a_lock));

    if (seg->s_as != &kas || size > seg->s_size ||
        addr < seg->s_base || addr + size > seg->s_base + seg->s_size)
        panic("segkmem_fault: bad args");

    /*
     * If it is one of segkp pages, call segkp_fault.
     */
    if (segkp_bitmap && seg == &kvseg &&
        BT_TEST(segkp_bitmap, btop((uintptr_t)(addr - seg->s_base))))
        return (SEGOP_FAULT(hat, segkp, addr, size, type, rw));

    if (rw != S_READ && rw != S_WRITE && rw != S_OTHER)
        return (FC_NOSUPPORT);

    npages = btopr(size);

    switch (type) {
    case F_SOFTLOCK:    /* lock down already-loaded translations */
        for (pg = 0; pg < npages; pg++) {
            pp = page_lookup(vp, (u_offset_t)(uintptr_t)addr,
                SE_SHARED);
            if (pp == NULL) {
                /*
                 * Hmm, no page. Does a kernel mapping
                 * exist for it?
                 */
                if (!hat_probe(kas.a_hat, addr)) {
                    addr -= PAGESIZE;
                    while (--pg >= 0) {
                        pp = page_find(vp, (u_offset_t)
                            (uintptr_t)addr);
                        if (pp)
                            page_unlock(pp);
                        addr -= PAGESIZE;
                    }
                    return (FC_NOMAP);
                }
            }
            addr += PAGESIZE;
        }
        if (rw == S_OTHER)
            hat_reserve(seg->s_as, addr, size);
        return (0);
    case F_SOFTUNLOCK:
        while (npages--) {
            pp = page_find(vp, (u_offset_t)(uintptr_t)addr);
            if (pp)
                page_unlock(pp);
            addr += PAGESIZE;
        }
        return (0);
    default:
        return (FC_NOSUPPORT);
    }
    /*NOTREACHED*/
}

static int
segkmem_setprot(struct seg *seg, caddr_t addr, size_t size, uint_t prot)
{
    ASSERT(RW_LOCK_HELD(&seg->s_as->a_lock));

    if (seg->s_as != &kas || size > seg->s_size ||
        addr < seg->s_base || addr + size > seg->s_base + seg->s_size)
        panic("segkmem_setprot: bad args");

    /*
     * If it is one of segkp pages, call segkp.
     */
    if (segkp_bitmap && seg == &kvseg &&
        BT_TEST(segkp_bitmap, btop((uintptr_t)(addr - seg->s_base))))
        return (SEGOP_SETPROT(segkp, addr, size, prot));

    if (prot == 0)
        hat_unload(kas.a_hat, addr, size, HAT_UNLOAD);
    else
        hat_chgprot(kas.a_hat, addr, size, prot);
    return (0);
}

/*
 * This is a dummy segkmem function overloaded to call segkp
 * when segkp is under the heap.
 */
/* ARGSUSED */
static int
segkmem_checkprot(struct seg *seg, caddr_t addr, size_t size, uint_t prot)
{
    ASSERT(RW_LOCK_HELD(&seg->s_as->a_lock));

    if (seg->s_as != &kas)
        segkmem_badop();

    /*
     * If it is one of segkp pages, call into segkp.
     */
    if (segkp_bitmap && seg == &kvseg &&
        BT_TEST(segkp_bitmap, btop((uintptr_t)(addr - seg->s_base))))
        return (SEGOP_CHECKPROT(segkp, addr, size, prot));

    segkmem_badop();
    return (0);
}

/*
 * This is a dummy segkmem function overloaded to call segkp
 * when segkp is under the heap.
 */
/* ARGSUSED */
static int
segkmem_kluster(struct seg *seg, caddr_t addr, ssize_t delta)
{
    ASSERT(RW_LOCK_HELD(&seg->s_as->a_lock));

    if (seg->s_as != &kas)
        segkmem_badop();

    /*
     * If it is one of segkp pages, call into segkp.
     */
    if (segkp_bitmap && seg == &kvseg &&
        BT_TEST(segkp_bitmap, btop((uintptr_t)(addr - seg->s_base))))
        return (SEGOP_KLUSTER(segkp, addr, delta));

    segkmem_badop();
    return (0);
}

static void
segkmem_xdump_range(void *arg, void *start, size_t size)
{
    struct as *as = arg;
    caddr_t addr = start;
    caddr_t addr_end = addr + size;

    while (addr < addr_end) {
        pfn_t pfn = hat_getpfnum(kas.a_hat, addr);
        if (pfn != PFN_INVALID && pfn <= physmax && pf_is_memory(pfn))
            dump_addpage(as, addr, pfn);
        addr += PAGESIZE;
        dump_timeleft = dump_timeout;
    }
}

static void
segkmem_dump_range(void *arg, void *start, size_t size)
{
    caddr_t addr = start;
    caddr_t addr_end = addr + size;

    /*
     * If we are about to start dumping the range of addresses we
     * carved out of the kernel heap for the large page heap walk
     * heap_lp_arena to find what segments are actually populated
     */
    if (SEGKMEM_USE_LARGEPAGES &&
        addr == heap_lp_base && addr_end == heap_lp_end &&
        vmem_size(heap_lp_arena, VMEM_ALLOC) < size) {
        vmem_walk(heap_lp_arena, VMEM_ALLOC | VMEM_REENTRANT,
            segkmem_xdump_range, arg);
    } else {
        segkmem_xdump_range(arg, start, size);
    }
}

static void
segkmem_dump(struct seg *seg)
{
    /*
     * The kernel's heap_arena (represented by kvseg) is a very large
     * VA space, most of which is typically unused.  To speed up dumping
     * we use vmem_walk() to quickly find the pieces of heap_arena that
     * are actually in use.  We do the same for heap32_arena and
     * heap_core.
     *
     * We specify VMEM_REENTRANT to vmem_walk() because dump_addpage()
     * may ultimately need to allocate memory.  Reentrant walks are
     * necessarily imperfect snapshots.  The kernel heap continues
     * to change during a live crash dump, for example.  For a normal
     * crash dump, however, we know that there won't be any other threads
     * messing with the heap.  Therefore, at worst, we may fail to dump
     * the pages that get allocated by the act of dumping; but we will
     * always dump every page that was allocated when the walk began.
     *
     * The other segkmem segments are dense (fully populated), so there's
     * no need to use this technique when dumping them.
     *
     * Note: when adding special dump handling for any new sparsely-
     * populated segments, be sure to add similar handling to the ::kgrep
     * code in mdb.
     */
    if (seg == &kvseg) {
        vmem_walk(heap_arena, VMEM_ALLOC | VMEM_REENTRANT,
            segkmem_dump_range, seg->s_as);
#ifndef __sparc
        vmem_walk(heaptext_arena, VMEM_ALLOC | VMEM_REENTRANT,
            segkmem_dump_range, seg->s_as);
#endif
    } else if (seg == &kvseg_core) {
        vmem_walk(heap_core_arena, VMEM_ALLOC | VMEM_REENTRANT,
            segkmem_dump_range, seg->s_as);
    } else if (seg == &kvseg32) {
        vmem_walk(heap32_arena, VMEM_ALLOC | VMEM_REENTRANT,
            segkmem_dump_range, seg->s_as);
        vmem_walk(heaptext_arena, VMEM_ALLOC | VMEM_REENTRANT,
            segkmem_dump_range, seg->s_as);
    } else if (seg == &kzioseg) {
        /*
         * We don't want to dump pages attached to kzioseg since they
         * contain file data from ZFS.  If this page's segment is
         * kzioseg return instead of writing it to the dump device.
         */
        return;
    } else {
        segkmem_dump_range(seg->s_as, seg->s_base, seg->s_size);
    }
}

/*
 * lock/unlock kmem pages over a given range [addr, addr+len).
 * Returns a shadow list of pages in ppp. If there are holes
 * in the range (e.g. some of the kernel mappings do not have
 * underlying page_ts) returns ENOTSUP so that as_pagelock()
 * will handle the range via as_fault(F_SOFTLOCK).
 */
/*ARGSUSED*/
static int
segkmem_pagelock(struct seg *seg, caddr_t addr, size_t len,
    page_t ***ppp, enum lock_type type, enum seg_rw rw)
{
    page_t **pplist, *pp;
    pgcnt_t npages;
    spgcnt_t pg;
    size_t nb;
    struct vnode *vp = seg->s_data;

    ASSERT(ppp != NULL);

    /*
     * If it is one of segkp pages, call into segkp.
     */
    if (segkp_bitmap && seg == &kvseg &&
        BT_TEST(segkp_bitmap, btop((uintptr_t)(addr - seg->s_base))))
        return (SEGOP_PAGELOCK(segkp, addr, len, ppp, type, rw));

    npages = btopr(len);
    nb = sizeof (page_t *) * npages;

    if (type == L_PAGEUNLOCK) {
        pplist = *ppp;
        ASSERT(pplist != NULL);

        for (pg = 0; pg < npages; pg++) {
            pp = pplist[pg];
            page_unlock(pp);
        }
        kmem_free(pplist, nb);
        return (0);
    }

    ASSERT(type == L_PAGELOCK);

    pplist = kmem_alloc(nb, KM_NOSLEEP);
    if (pplist == NULL) {
        *ppp = NULL;
        return (ENOTSUP);   /* take the slow path */
    }

    for (pg = 0; pg < npages; pg++) {
        pp = page_lookup(vp, (u_offset_t)(uintptr_t)addr, SE_SHARED);
        if (pp == NULL) {
            while (--pg >= 0)
                page_unlock(pplist[pg]);
            kmem_free(pplist, nb);
            *ppp = NULL;
            return (ENOTSUP);
        }
        pplist[pg] = pp;
        addr += PAGESIZE;
    }

    *ppp = pplist;
    return (0);
}

/*
 * This is a dummy segkmem function overloaded to call segkp
 * when segkp is under the heap.
 */
/* ARGSUSED */
static int
segkmem_getmemid(struct seg *seg, caddr_t addr, memid_t *memidp)
{
    ASSERT(RW_LOCK_HELD(&seg->s_as->a_lock));

    if (seg->s_as != &kas)
        segkmem_badop();

    /*
     * If it is one of segkp pages, call into segkp.
     */
    if (segkp_bitmap && seg == &kvseg &&
        BT_TEST(segkp_bitmap, btop((uintptr_t)(addr - seg->s_base))))
        return (SEGOP_GETMEMID(segkp, addr, memidp));

    segkmem_badop();
    return (0);
}

/*ARGSUSED*/
static lgrp_mem_policy_info_t *
segkmem_getpolicy(struct seg *seg, caddr_t addr)
{
    return (NULL);
}

/*ARGSUSED*/
static int
segkmem_capable(struct seg *seg, segcapability_t capability)
{
    if (capability == S_CAPABILITY_NOMINFLT)
        return (1);
    return (0);
}

static struct seg_ops segkmem_ops = {
    SEGKMEM_BADOP(int),     /* dup */
    SEGKMEM_BADOP(int),     /* unmap */
    SEGKMEM_BADOP(void),        /* free */
    segkmem_fault,
    SEGKMEM_BADOP(faultcode_t), /* faulta */
    segkmem_setprot,
    segkmem_checkprot,
    segkmem_kluster,
    SEGKMEM_BADOP(size_t),      /* swapout */
    SEGKMEM_BADOP(int),     /* sync */
    SEGKMEM_BADOP(size_t),      /* incore */
    SEGKMEM_BADOP(int),     /* lockop */
    SEGKMEM_BADOP(int),     /* getprot */
    SEGKMEM_BADOP(u_offset_t),  /* getoffset */
    SEGKMEM_BADOP(int),     /* gettype */
    SEGKMEM_BADOP(int),     /* getvp */
    SEGKMEM_BADOP(int),     /* advise */
    segkmem_dump,
    segkmem_pagelock,
    SEGKMEM_BADOP(int),     /* setpgsz */
    segkmem_getmemid,
    segkmem_getpolicy,      /* getpolicy */
    segkmem_capable,        /* capable */
};

int
segkmem_zio_create(struct seg *seg)
{
    ASSERT(seg->s_as == &kas && RW_WRITE_HELD(&kas.a_lock));
    seg->s_ops = &segkmem_ops;
    seg->s_data = &zvp;
    kas.a_size += seg->s_size;
    return (0);
}

int
segkmem_create(struct seg *seg)
{
    ASSERT(seg->s_as == &kas && RW_WRITE_HELD(&kas.a_lock));
    seg->s_ops = &segkmem_ops;
    seg->s_data = &kvp;
    kas.a_size += seg->s_size;
    return (0);
}

/*ARGSUSED*/
page_t *
segkmem_page_create(void *addr, size_t size, int vmflag, void *arg)
{
    struct seg kseg;
    int pgflags;
    struct vnode *vp = arg;

    if (vp == NULL)
        vp = &kvp;

    kseg.s_as = &kas;
    pgflags = PG_EXCL;

    if (segkmem_reloc == 0 || (vmflag & VM_NORELOC))
        pgflags |= PG_NORELOC;
    if ((vmflag & VM_NOSLEEP) == 0)
        pgflags |= PG_WAIT;
    if (vmflag & VM_PANIC)
        pgflags |= PG_PANIC;
    if (vmflag & VM_PUSHPAGE)
        pgflags |= PG_PUSHPAGE;
    if (vmflag & VM_NORMALPRI) {
        ASSERT(vmflag & VM_NOSLEEP);
        pgflags |= PG_NORMALPRI;
    }

    return (page_create_va(vp, (u_offset_t)(uintptr_t)addr, size,
        pgflags, &kseg, addr));
}

/*
 * Allocate pages to back the virtual address range [addr, addr + size).
 * If addr is NULL, allocate the virtual address space as well.
 */
void *
segkmem_xalloc(vmem_t *vmp, void *inaddr, size_t size, int vmflag, uint_t attr,
    page_t *(*page_create_func)(void *, size_t, int, void *), void *pcarg)
{
    page_t *ppl;
    caddr_t addr = inaddr;
    pgcnt_t npages = btopr(size);
    int allocflag;

    if (inaddr == NULL && (addr = vmem_alloc(vmp, size, vmflag)) == NULL)
        return (NULL);

    ASSERT(((uintptr_t)addr & PAGEOFFSET) == 0);

    if (page_resv(npages, vmflag & VM_KMFLAGS) == 0) {
        if (inaddr == NULL)
            vmem_free(vmp, addr, size);
        return (NULL);
    }

    ppl = page_create_func(addr, size, vmflag, pcarg);
    if (ppl == NULL) {
        if (inaddr == NULL)
            vmem_free(vmp, addr, size);
        page_unresv(npages);
        return (NULL);
    }

    /*
     * Under certain conditions, we need to let the HAT layer know
     * that it cannot safely allocate memory.  Allocations from
     * the hat_memload vmem arena always need this, to prevent
     * infinite recursion.
     *
     * In addition, the x86 hat cannot safely do memory
     * allocations while in vmem_populate(), because there
     * is no simple bound on its usage.
     */
    if (vmflag & VM_MEMLOAD)
        allocflag = HAT_NO_KALLOC;
#if defined(__x86)
    else if (vmem_is_populator())
        allocflag = HAT_NO_KALLOC;
#endif
    else
        allocflag = 0;

    while (ppl != NULL) {
        page_t *pp = ppl;
        page_sub(&ppl, pp);
        ASSERT(page_iolock_assert(pp));
        ASSERT(PAGE_EXCL(pp));
        page_io_unlock(pp);
        hat_memload(kas.a_hat, (caddr_t)(uintptr_t)pp->p_offset, pp,
            (PROT_ALL & ~PROT_USER) | HAT_NOSYNC | attr,
            HAT_LOAD_LOCK | allocflag);
        pp->p_lckcnt = 1;
#if defined(__x86)
        page_downgrade(pp);
#else
        if (vmflag & SEGKMEM_SHARELOCKED)
            page_downgrade(pp);
        else
            page_unlock(pp);
#endif
    }

    return (addr);
}

static void *
segkmem_alloc_vn(vmem_t *vmp, size_t size, int vmflag, struct vnode *vp)
{
    void *addr;
    segkmem_gc_list_t *gcp, **prev_gcpp;

    ASSERT(vp != NULL);

    if (kvseg.s_base == NULL) {
#ifndef __sparc
        if (bootops->bsys_alloc == NULL)
            halt("Memory allocation between bop_alloc() and "
                "kmem_alloc().\n");
#endif

        /*
         * There's not a lot of memory to go around during boot,
         * so recycle it if we can.
         */
        for (prev_gcpp = &segkmem_gc_list; (gcp = *prev_gcpp) != NULL;
            prev_gcpp = &gcp->gc_next) {
            if (gcp->gc_arena == vmp && gcp->gc_size == size) {
                *prev_gcpp = gcp->gc_next;
                return (gcp);
            }
        }

        addr = vmem_alloc(vmp, size, vmflag | VM_PANIC);
        if (boot_alloc(addr, size, BO_NO_ALIGN) != addr)
            panic("segkmem_alloc: boot_alloc failed");
        return (addr);
    }
    return (segkmem_xalloc(vmp, NULL, size, vmflag, 0,
        segkmem_page_create, vp));
}

void *
segkmem_alloc(vmem_t *vmp, size_t size, int vmflag)
{
    return (segkmem_alloc_vn(vmp, size, vmflag, &kvp));
}

void *
segkmem_zio_alloc(vmem_t *vmp, size_t size, int vmflag)
{
    return (segkmem_alloc_vn(vmp, size, vmflag, &zvp));
}

/*
 * Any changes to this routine must also be carried over to
 * devmap_free_pages() in the seg_dev driver. This is because
 * we currently don't have a special kernel segment for non-paged
 * kernel memory that is exported by drivers to user space.
 */
static void
segkmem_free_vn(vmem_t *vmp, void *inaddr, size_t size, struct vnode *vp,
    void (*func)(page_t *))
{
    page_t *pp;
    caddr_t addr = inaddr;
    caddr_t eaddr;
    pgcnt_t npages = btopr(size);

    ASSERT(((uintptr_t)addr & PAGEOFFSET) == 0);
    ASSERT(vp != NULL);

    if (kvseg.s_base == NULL) {
        segkmem_gc_list_t *gc = inaddr;
        gc->gc_arena = vmp;
        gc->gc_size = size;
        gc->gc_next = segkmem_gc_list;
        segkmem_gc_list = gc;
        return;
    }

    hat_unload(kas.a_hat, addr, size, HAT_UNLOAD_UNLOCK);

    for (eaddr = addr + size; addr < eaddr; addr += PAGESIZE) {
#if defined(__x86)
        pp = page_find(vp, (u_offset_t)(uintptr_t)addr);
        if (pp == NULL)
            panic("segkmem_free: page not found");
        if (!page_tryupgrade(pp)) {
            /*
             * Some other thread has a sharelock. Wait for
             * it to drop the lock so we can free this page.
             */
            page_unlock(pp);
            pp = page_lookup(vp, (u_offset_t)(uintptr_t)addr,
                SE_EXCL);
        }
#else
        pp = page_lookup(vp, (u_offset_t)(uintptr_t)addr, SE_EXCL);
#endif
        if (pp == NULL)
            panic("segkmem_free: page not found");
        /* Clear p_lckcnt so page_destroy() doesn't update availrmem */
        pp->p_lckcnt = 0;
        if (func)
            func(pp);
        else
            page_destroy(pp, 0);
    }
    if (func == NULL)
        page_unresv(npages);

    if (vmp != NULL)
        vmem_free(vmp, inaddr, size);

}

void
segkmem_xfree(vmem_t *vmp, void *inaddr, size_t size, void (*func)(page_t *))
{
    segkmem_free_vn(vmp, inaddr, size, &kvp, func);
}

void
segkmem_free(vmem_t *vmp, void *inaddr, size_t size)
{
    segkmem_free_vn(vmp, inaddr, size, &kvp, NULL);
}

void
segkmem_zio_free(vmem_t *vmp, void *inaddr, size_t size)
{
    segkmem_free_vn(vmp, inaddr, size, &zvp, NULL);
}

void
segkmem_gc(void)
{
    ASSERT(kvseg.s_base != NULL);
    while (segkmem_gc_list != NULL) {
        segkmem_gc_list_t *gc = segkmem_gc_list;
        segkmem_gc_list = gc->gc_next;
        segkmem_free(gc->gc_arena, gc, gc->gc_size);
    }
}

/*
 * Legacy entry points from here to end of file.
 */
void
segkmem_mapin(struct seg *seg, void *addr, size_t size, uint_t vprot,
    pfn_t pfn, uint_t flags)
{
    hat_unload(seg->s_as->a_hat, addr, size, HAT_UNLOAD_UNLOCK);
    hat_devload(seg->s_as->a_hat, addr, size, pfn, vprot,
        flags | HAT_LOAD_LOCK);
}

void
segkmem_mapout(struct seg *seg, void *addr, size_t size)
{
    hat_unload(seg->s_as->a_hat, addr, size, HAT_UNLOAD_UNLOCK);
}

void *
kmem_getpages(pgcnt_t npages, int kmflag)
{
    return (kmem_alloc(ptob(npages), kmflag));
}

void
kmem_freepages(void *addr, pgcnt_t npages)
{
    kmem_free(addr, ptob(npages));
}

/*
 * segkmem_page_create_large() allocates a large page to be used for the kmem
 * caches. If kpr is enabled we ask for a relocatable page unless requested
 * otherwise. If kpr is disabled we have to ask for a non-reloc page
 */
static page_t *
segkmem_page_create_large(void *addr, size_t size, int vmflag, void *arg)
{
    int pgflags;

    pgflags = PG_EXCL;

    if (segkmem_reloc == 0 || (vmflag & VM_NORELOC))
        pgflags |= PG_NORELOC;
    if (!(vmflag & VM_NOSLEEP))
        pgflags |= PG_WAIT;
    if (vmflag & VM_PUSHPAGE)
        pgflags |= PG_PUSHPAGE;
    if (vmflag & VM_NORMALPRI)
        pgflags |= PG_NORMALPRI;

    return (page_create_va_large(&kvp, (u_offset_t)(uintptr_t)addr, size,
        pgflags, &kvseg, addr, arg));
}

/*
 * Allocate a large page to back the virtual address range
 * [addr, addr + size).  If addr is NULL, allocate the virtual address
 * space as well.
 */
static void *
segkmem_xalloc_lp(vmem_t *vmp, void *inaddr, size_t size, int vmflag,
    uint_t attr, page_t *(*page_create_func)(void *, size_t, int, void *),
    void *pcarg)
{
    caddr_t addr = inaddr, pa;
    size_t  lpsize = segkmem_lpsize;
    pgcnt_t npages = btopr(size);
    pgcnt_t nbpages = btop(lpsize);
    pgcnt_t nlpages = size >> segkmem_lpshift;
    size_t  ppasize = nbpages * sizeof (page_t *);
    page_t *pp, *rootpp, **ppa, *pplist = NULL;
    int i;

    vmflag |= VM_NOSLEEP;

    if (page_resv(npages, vmflag & VM_KMFLAGS) == 0) {
        return (NULL);
    }

    /*
     * allocate an array we need for hat_memload_array.
     * we use a separate arena to avoid recursion.
     * we will not need this array when hat_memload_array learns pp++
     */
    if ((ppa = vmem_alloc(segkmem_ppa_arena, ppasize, vmflag)) == NULL) {
        goto fail_array_alloc;
    }

    if (inaddr == NULL && (addr = vmem_alloc(vmp, size, vmflag)) == NULL)
        goto fail_vmem_alloc;

    ASSERT(((uintptr_t)addr & (lpsize - 1)) == 0);

    /* create all the pages */
    for (pa = addr, i = 0; i < nlpages; i++, pa += lpsize) {
        if ((pp = page_create_func(pa, lpsize, vmflag, pcarg)) == NULL)
            goto fail_page_create;
        page_list_concat(&pplist, &pp);
    }

    /* at this point we have all the resource to complete the request */
    while ((rootpp = pplist) != NULL) {
        for (i = 0; i < nbpages; i++) {
            ASSERT(pplist != NULL);
            pp = pplist;
            page_sub(&pplist, pp);
            ASSERT(page_iolock_assert(pp));
            page_io_unlock(pp);
            ppa[i] = pp;
        }
        /*
         * Load the locked entry. It's OK to preload the entry into the
         * TSB since we now support large mappings in the kernel TSB.
         */
        hat_memload_array(kas.a_hat,
            (caddr_t)(uintptr_t)rootpp->p_offset, lpsize,
            ppa, (PROT_ALL & ~PROT_USER) | HAT_NOSYNC | attr,
            HAT_LOAD_LOCK);

        for (--i; i >= 0; --i) {
            ppa[i]->p_lckcnt = 1;
            page_unlock(ppa[i]);
        }
    }

    vmem_free(segkmem_ppa_arena, ppa, ppasize);
    return (addr);

fail_page_create:
    while ((rootpp = pplist) != NULL) {
        for (i = 0, pp = pplist; i < nbpages; i++, pp = pplist) {
            ASSERT(pp != NULL);
            page_sub(&pplist, pp);
            ASSERT(page_iolock_assert(pp));
            page_io_unlock(pp);
        }
        page_destroy_pages(rootpp);
    }

    if (inaddr == NULL)
        vmem_free(vmp, addr, size);

fail_vmem_alloc:
    vmem_free(segkmem_ppa_arena, ppa, ppasize);

fail_array_alloc:
    page_unresv(npages);

    return (NULL);
}

static void
segkmem_free_one_lp(caddr_t addr, size_t size)
{
    page_t      *pp, *rootpp = NULL;
    pgcnt_t     pgs_left = btopr(size);

    ASSERT(size == segkmem_lpsize);

    hat_unload(kas.a_hat, addr, size, HAT_UNLOAD_UNLOCK);

    for (; pgs_left > 0; addr += PAGESIZE, pgs_left--) {
        pp = page_lookup(&kvp, (u_offset_t)(uintptr_t)addr, SE_EXCL);
        if (pp == NULL)
            panic("segkmem_free_one_lp: page not found");
        ASSERT(PAGE_EXCL(pp));
        pp->p_lckcnt = 0;
        if (rootpp == NULL)
            rootpp = pp;
    }
    ASSERT(rootpp != NULL);
    page_destroy_pages(rootpp);

    /* page_unresv() is done by the caller */
}

/*
 * This function is called to import new spans into the vmem arenas like
 * kmem_default_arena and kmem_oversize_arena. It first tries to import
 * spans from large page arena - kmem_lp_arena. In order to do this it might
 * have to "upgrade the requested size" to kmem_lp_arena quantum. If
 * it was not able to satisfy the upgraded request it then calls regular
 * segkmem_alloc() that satisfies the request by importing from "*vmp" arena
 */
/*ARGSUSED*/
void *
segkmem_alloc_lp(vmem_t *vmp, size_t *sizep, size_t align, int vmflag)
{
    size_t size;
    kthread_t *t = curthread;
    segkmem_lpcb_t *lpcb = &segkmem_lpcb;

    ASSERT(sizep != NULL);

    size = *sizep;

    if (lpcb->lp_uselp && !(t->t_flag & T_PANIC) &&
        !(vmflag & SEGKMEM_SHARELOCKED)) {

        size_t kmemlp_qnt = segkmem_kmemlp_quantum;
        size_t asize = P2ROUNDUP(size, kmemlp_qnt);
        void  *addr = NULL;
        ulong_t *lpthrtp = &lpcb->lp_throttle;
        ulong_t lpthrt = *lpthrtp;
        int dowakeup = 0;
        int doalloc = 1;

        ASSERT(kmem_lp_arena != NULL);
        ASSERT(asize >= size);

        if (lpthrt != 0) {
            /* try to update the throttle value */
            lpthrt = atomic_add_long_nv(lpthrtp, 1);
            if (lpthrt >= segkmem_lpthrottle_max) {
                lpthrt = atomic_cas_ulong(lpthrtp, lpthrt,
                    segkmem_lpthrottle_max / 4);
            }

            /*
             * when we get above throttle start do an exponential
             * backoff at trying large pages and reaping
             */
            if (lpthrt > segkmem_lpthrottle_start &&
                (lpthrt & (lpthrt - 1))) {
                lpcb->allocs_throttled++;
                lpthrt--;
                if ((lpthrt & (lpthrt - 1)) == 0)
                    kmem_reap();
                return (segkmem_alloc(vmp, size, vmflag));
            }
        }

        if (!(vmflag & VM_NOSLEEP) &&
            segkmem_heaplp_quantum >= (8 * kmemlp_qnt) &&
            vmem_size(kmem_lp_arena, VMEM_FREE) <= kmemlp_qnt &&
            asize < (segkmem_heaplp_quantum - kmemlp_qnt)) {

            /*
             * we are low on free memory in kmem_lp_arena
             * we let only one guy to allocate heap_lp
             * quantum size chunk that everybody is going to
             * share
             */
            mutex_enter(&lpcb->lp_lock);

            if (lpcb->lp_wait) {

                /* we are not the first one - wait */
                cv_wait(&lpcb->lp_cv, &lpcb->lp_lock);
                if (vmem_size(kmem_lp_arena, VMEM_FREE) <
                    kmemlp_qnt)  {
                    doalloc = 0;
                }
            } else if (vmem_size(kmem_lp_arena, VMEM_FREE) <=
                kmemlp_qnt) {

                /*
                 * we are the first one, make sure we import
                 * a large page
                 */
                if (asize == kmemlp_qnt)
                    asize += kmemlp_qnt;
                dowakeup = 1;
                lpcb->lp_wait = 1;
            }

            mutex_exit(&lpcb->lp_lock);
        }

        /*
         * VM_ABORT flag prevents sleeps in vmem_xalloc when
         * large pages are not available. In that case this allocation
         * attempt will fail and we will retry allocation with small
         * pages. We also do not want to panic if this allocation fails
         * because we are going to retry.
         */
        if (doalloc) {
            addr = vmem_alloc(kmem_lp_arena, asize,
                (vmflag | VM_ABORT) & ~VM_PANIC);

            if (dowakeup) {
                mutex_enter(&lpcb->lp_lock);
                ASSERT(lpcb->lp_wait != 0);
                lpcb->lp_wait = 0;
                cv_broadcast(&lpcb->lp_cv);
                mutex_exit(&lpcb->lp_lock);
            }
        }

        if (addr != NULL) {
            *sizep = asize;
            *lpthrtp = 0;
            return (addr);
        }

        if (vmflag & VM_NOSLEEP)
            lpcb->nosleep_allocs_failed++;
        else
            lpcb->sleep_allocs_failed++;
        lpcb->alloc_bytes_failed += size;

        /* if large page throttling is not started yet do it */
        if (segkmem_use_lpthrottle && lpthrt == 0) {
            lpthrt = atomic_cas_ulong(lpthrtp, lpthrt, 1);
        }
    }
    return (segkmem_alloc(vmp, size, vmflag));
}

void
segkmem_free_lp(vmem_t *vmp, void *inaddr, size_t size)
{
    if (kmem_lp_arena == NULL || !IS_KMEM_VA_LARGEPAGE((caddr_t)inaddr)) {
        segkmem_free(vmp, inaddr, size);
    } else {
        vmem_free(kmem_lp_arena, inaddr, size);
    }
}

/*
 * segkmem_alloc_lpi() imports virtual memory from large page heap arena
 * into kmem_lp arena. In the process it maps the imported segment with
 * large pages
 */
static void *
segkmem_alloc_lpi(vmem_t *vmp, size_t size, int vmflag)
{
    segkmem_lpcb_t *lpcb = &segkmem_lpcb;
    void  *addr;

    ASSERT(size != 0);
    ASSERT(vmp == heap_lp_arena);

    /* do not allow large page heap grow beyound limits */
    if (vmem_size(vmp, VMEM_ALLOC) >= segkmem_kmemlp_max) {
        lpcb->allocs_limited++;
        return (NULL);
    }

    addr = segkmem_xalloc_lp(vmp, NULL, size, vmflag, 0,
        segkmem_page_create_large, NULL);
    return (addr);
}

/*
 * segkmem_free_lpi() returns virtual memory back into large page heap arena
 * from kmem_lp arena. Beore doing this it unmaps the segment and frees
 * large pages used to map it.
 */
static void
segkmem_free_lpi(vmem_t *vmp, void *inaddr, size_t size)
{
    pgcnt_t     nlpages = size >> segkmem_lpshift;
    size_t      lpsize = segkmem_lpsize;
    caddr_t     addr = inaddr;
    pgcnt_t     npages = btopr(size);
    int     i;

    ASSERT(vmp == heap_lp_arena);
    ASSERT(IS_KMEM_VA_LARGEPAGE(addr));
    ASSERT(((uintptr_t)inaddr & (lpsize - 1)) == 0);

    for (i = 0; i < nlpages; i++) {
        segkmem_free_one_lp(addr, lpsize);
        addr += lpsize;
    }

    page_unresv(npages);

    vmem_free(vmp, inaddr, size);
}

/*
 * This function is called at system boot time by kmem_init right after
 * /etc/system file has been read. It checks based on hardware configuration
 * and /etc/system settings if system is going to use large pages. The
 * initialiazation necessary to actually start using large pages
 * happens later in the process after segkmem_heap_lp_init() is called.
 */
int
segkmem_lpsetup()
{
    int use_large_pages = 0;

#ifdef __sparc

    size_t memtotal = physmem * PAGESIZE;

    if (heap_lp_base == NULL) {
        segkmem_lpsize = PAGESIZE;
        return (0);
    }

    /* get a platform dependent value of large page size for kernel heap */
    segkmem_lpsize = get_segkmem_lpsize(segkmem_lpsize);

    if (segkmem_lpsize <= PAGESIZE) {
        /*
         * put virtual space reserved for the large page kernel
         * back to the regular heap
         */
        vmem_xfree(heap_arena, heap_lp_base,
            heap_lp_end - heap_lp_base);
        heap_lp_base = NULL;
        heap_lp_end = NULL;
        segkmem_lpsize = PAGESIZE;
        return (0);
    }

    /* set heap_lp quantum if necessary */
    if (segkmem_heaplp_quantum == 0 ||
        (segkmem_heaplp_quantum & (segkmem_heaplp_quantum - 1)) ||
        P2PHASE(segkmem_heaplp_quantum, segkmem_lpsize)) {
        segkmem_heaplp_quantum = segkmem_lpsize;
    }

    /* set kmem_lp quantum if necessary */
    if (segkmem_kmemlp_quantum == 0 ||
        (segkmem_kmemlp_quantum & (segkmem_kmemlp_quantum - 1)) ||
        segkmem_kmemlp_quantum > segkmem_heaplp_quantum) {
        segkmem_kmemlp_quantum = segkmem_heaplp_quantum;
    }

    /* set total amount of memory allowed for large page kernel heap */
    if (segkmem_kmemlp_max == 0) {
        if (segkmem_kmemlp_pcnt == 0 || segkmem_kmemlp_pcnt > 100)
            segkmem_kmemlp_pcnt = 12;
        segkmem_kmemlp_max = (memtotal * segkmem_kmemlp_pcnt) / 100;
    }
    segkmem_kmemlp_max = P2ROUNDUP(segkmem_kmemlp_max,
        segkmem_heaplp_quantum);

    /* fix lp kmem preallocation request if necesssary */
    if (segkmem_kmemlp_min) {
        segkmem_kmemlp_min = P2ROUNDUP(segkmem_kmemlp_min,
            segkmem_heaplp_quantum);
        if (segkmem_kmemlp_min > segkmem_kmemlp_max)
            segkmem_kmemlp_min = segkmem_kmemlp_max;
    }

    use_large_pages = 1;
    segkmem_lpszc = page_szc(segkmem_lpsize);
    segkmem_lpshift = page_get_shift(segkmem_lpszc);

#endif
    return (use_large_pages);
}

void
segkmem_zio_init(void *zio_mem_base, size_t zio_mem_size)
{
    ASSERT(zio_mem_base != NULL);
    ASSERT(zio_mem_size != 0);

    /*
     * To reduce VA space fragmentation, we set up quantum caches for the
     * smaller sizes;  we chose 32k because that translates to 128k VA
     * slabs, which matches nicely with the common 128k zio_data bufs.
     */
    zio_arena = vmem_create("zfs_file_data", zio_mem_base, zio_mem_size,
        PAGESIZE, NULL, NULL, NULL, 32 * 1024, VM_SLEEP);

    zio_alloc_arena = vmem_create("zfs_file_data_buf", NULL, 0, PAGESIZE,
        segkmem_zio_alloc, segkmem_zio_free, zio_arena, 0, VM_SLEEP);

    ASSERT(zio_arena != NULL);
    ASSERT(zio_alloc_arena != NULL);
}

#ifdef __sparc


static void *
segkmem_alloc_ppa(vmem_t *vmp, size_t size, int vmflag)
{
    size_t ppaquantum = btopr(segkmem_lpsize) * sizeof (page_t *);
    void   *addr;

    if (ppaquantum <= PAGESIZE)
        return (segkmem_alloc(vmp, size, vmflag));

    ASSERT((size & (ppaquantum - 1)) == 0);

    addr = vmem_xalloc(vmp, size, ppaquantum, 0, 0, NULL, NULL, vmflag);
    if (addr != NULL && segkmem_xalloc(vmp, addr, size, vmflag, 0,
        segkmem_page_create, NULL) == NULL) {
        vmem_xfree(vmp, addr, size);
        addr = NULL;
    }

    return (addr);
}

static void
segkmem_free_ppa(vmem_t *vmp, void *addr, size_t size)
{
    size_t ppaquantum = btopr(segkmem_lpsize) * sizeof (page_t *);

    ASSERT(addr != NULL);

    if (ppaquantum <= PAGESIZE) {
        segkmem_free(vmp, addr, size);
    } else {
        segkmem_free(NULL, addr, size);
        vmem_xfree(vmp, addr, size);
    }
}

void
segkmem_heap_lp_init()
{
    segkmem_lpcb_t *lpcb = &segkmem_lpcb;
    size_t heap_lp_size = heap_lp_end - heap_lp_base;
    size_t lpsize = segkmem_lpsize;
    size_t ppaquantum;
    void   *addr;

    if (segkmem_lpsize <= PAGESIZE) {
        ASSERT(heap_lp_base == NULL);
        ASSERT(heap_lp_end == NULL);
        return;
    }

    ASSERT(segkmem_heaplp_quantum >= lpsize);
    ASSERT((segkmem_heaplp_quantum & (lpsize - 1)) == 0);
    ASSERT(lpcb->lp_uselp == 0);
    ASSERT(heap_lp_base != NULL);
    ASSERT(heap_lp_end != NULL);
    ASSERT(heap_lp_base < heap_lp_end);
    ASSERT(heap_lp_arena == NULL);
    ASSERT(((uintptr_t)heap_lp_base & (lpsize - 1)) == 0);
    ASSERT(((uintptr_t)heap_lp_end & (lpsize - 1)) == 0);

    /* create large page heap arena */
    heap_lp_arena = vmem_create("heap_lp", heap_lp_base, heap_lp_size,
        segkmem_heaplp_quantum, NULL, NULL, NULL, 0, VM_SLEEP);

    ASSERT(heap_lp_arena != NULL);

    /* This arena caches memory already mapped by large pages */
    kmem_lp_arena = vmem_create("kmem_lp", NULL, 0, segkmem_kmemlp_quantum,
        segkmem_alloc_lpi, segkmem_free_lpi, heap_lp_arena, 0, VM_SLEEP);

    ASSERT(kmem_lp_arena != NULL);

    mutex_init(&lpcb->lp_lock, NULL, MUTEX_DEFAULT, NULL);
    cv_init(&lpcb->lp_cv, NULL, CV_DEFAULT, NULL);

    /*
     * this arena is used for the array of page_t pointers necessary
     * to call hat_mem_load_array
     */
    ppaquantum = btopr(lpsize) * sizeof (page_t *);
    segkmem_ppa_arena = vmem_create("segkmem_ppa", NULL, 0, ppaquantum,
        segkmem_alloc_ppa, segkmem_free_ppa, heap_arena, ppaquantum,
        VM_SLEEP);

    ASSERT(segkmem_ppa_arena != NULL);

    /* prealloacate some memory for the lp kernel heap */
    if (segkmem_kmemlp_min) {

        ASSERT(P2PHASE(segkmem_kmemlp_min,
            segkmem_heaplp_quantum) == 0);

        if ((addr = segkmem_alloc_lpi(heap_lp_arena,
            segkmem_kmemlp_min, VM_SLEEP)) != NULL) {

            addr = vmem_add(kmem_lp_arena, addr,
                segkmem_kmemlp_min, VM_SLEEP);
            ASSERT(addr != NULL);
        }
    }

    lpcb->lp_uselp = 1;
}

#endif