sys/uvm/uvm_pglist.c

#define VM_PAGE_ALLOC_MEMORY_STATS

/*-
 * Copyright (c) 1997 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the NetBSD
 *      Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * uvm_pglist.c: pglist functions
 *
 * XXX: was part of uvm_page but has an incompatable copyright so it
 * gets its own file now.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/proc.h>

#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/vm_kern.h>

#include <sys/syscallargs.h>

#include <uvm/uvm.h>

#ifdef VM_PAGE_ALLOC_MEMORY_STATS
#define	STAT_INCR(v)	(v)++
#define	STAT_DECR(v)	do { \
		if ((v) == 0) \
			printf("%s:%d -- Already 0!\n", __FILE__, __LINE__); \
		else \
			(v)--; \
	} while (0)
u_long	uvm_pglistalloc_npages;
#else
#define	STAT_INCR(v)
#define	STAT_DECR(v)
#endif

/*
 * uvm_pglistalloc: allocate a list of pages
 *
 * => allocated pages are placed at the tail of rlist.  rlist is
 *    assumed to be properly initialized by caller.
 * => returns 0 on success or errno on failure
 * => XXX: implementation allocates only a single segment, also
 *	might be able to better advantage of vm_physeg[].
 * => doesn't take into account clean non-busy pages on inactive list
 *	that could be used(?)
 * => params:
 *	size		the size of the allocation, rounded to page size.
 *	low		the low address of the allowed allocation range.
 *	high		the high address of the allowed allocation range.
 *	alignment	memory must be aligned to this power-of-two boundary.
 *	boundary	no segment in the allocation may cross this
 *			power-of-two boundary (relative to zero).
 */

int uvm_pglistalloc(size, low, high, alignment, boundary, rlist, nsegs, waitok)

vm_size_t size;
vm_offset_t low, high, alignment, boundary;
struct pglist *rlist;
int nsegs, waitok;

{
  vm_offset_t try, idxpa, lastidxpa;
  int psi;
  struct vm_page *pgs;
  int s, tryidx, idx, end, error;
  vm_page_t m;
  u_long pagemask;
#ifdef DEBUG
  vm_page_t tp;
#endif

#ifdef DIAGNOSTIC
  if ((alignment & (alignment - 1)) != 0)
    panic("vm_page_alloc_memory: alignment must be power of 2");

  if ((boundary & (boundary - 1)) != 0)
    panic("vm_page_alloc_memory: boundary must be power of 2");
#endif

  /*
   * Our allocations are always page granularity, so our alignment
   * must be, too.
   */
  if (alignment < PAGE_SIZE)
    alignment = PAGE_SIZE;

  size = round_page(size);
  try = roundup(low, alignment);

  if (boundary != 0 && boundary < size)
    return (EINVAL);

  pagemask = ~(boundary - 1);

  /* Default to "lose". */
  error = ENOMEM;

  /*
   * Block all memory allocation and lock the free list.
   */
  s = splimp();
  uvm_lock_fpageq();            /* lock free page queue */

  /* Are there even any free pages? */
  if (uvm.page_free.tqh_first == NULL)
    goto out;

  for (;; try += alignment) {
    if (try + size > high) {
      /*
       * We've run past the allowable range.
       */
      goto out;
    }

    /*
     * Make sure this is a managed physical page.
     */

    if ((psi = vm_physseg_find(atop(try), &idx)) == -1)
      continue; /* managed? */
    if (vm_physseg_find(atop(try + size), NULL) != psi)
      continue; /* end must be in this segment */

    tryidx = idx;
    end = idx + (size / PAGE_SIZE);
    pgs = vm_physmem[psi].pgs;

    /*
     * Found a suitable starting page.  See of the range is free.
     */
    for (; idx < end; idx++) {
      if (VM_PAGE_IS_FREE(&pgs[idx]) == 0) {
	/*
	 * Page not available.
	 */
	break;
      }

      idxpa = VM_PAGE_TO_PHYS(&pgs[idx]);

      if (idx > tryidx) {
	lastidxpa = VM_PAGE_TO_PHYS(&pgs[idx - 1]);

	if ((lastidxpa + PAGE_SIZE) != idxpa) {
	  /*
	   * Region not contiguous.
	   */
	  break;
	}
	if (boundary != 0 && ((lastidxpa ^ idxpa) & pagemask) != 0) {
	  /*
	   * Region crosses boundary.
	   */
	  break;
	}
      }
    }

    if (idx == end) {
      /*
       * Woo hoo!  Found one.
       */
      break;
    }
  }

  /*
   * we have a chunk of memory that conforms to the requested constraints.
   */
  idx = tryidx;
  while (idx < end) {
    m = &pgs[idx];
#ifdef DEBUG
    for (tp = uvm.page_free.tqh_first; tp != NULL;
	 tp = tp->pageq.tqe_next) {
      if (tp == m)
	break;
    }
    if (tp == NULL)
      panic("uvm_pglistalloc: page not on freelist");
#endif
    TAILQ_REMOVE(&uvm.page_free, m, pageq);
    uvmexp.free--;
    m->flags = PG_CLEAN;
    m->pqflags = 0;
    m->uobject = NULL;
    m->uanon = NULL;
    m->wire_count = 0;
    m->loan_count = 0;
    TAILQ_INSERT_TAIL(rlist, m, pageq);
    idx++;
    STAT_INCR(uvm_pglistalloc_npages);
  }
  error = 0;

out:
  uvm_unlock_fpageq();
  splx(s);

  /*
   * check to see if we need to generate some free pages waking
   * the pagedaemon.
   * XXX: we read uvm.free without locking
   */

  if (uvmexp.free < uvmexp.freemin ||
      (uvmexp.free < uvmexp.freetarg && uvmexp.inactive < uvmexp.inactarg)) {

    thread_wakeup(&uvm.pagedaemon);
  }

  return (error);
}

/*
 * uvm_pglistfree: free a list of pages
 *
 * => pages should already be unmapped
 */

void uvm_pglistfree(list)

struct pglist *list;

{
  vm_page_t m;
  int s;

  /*
   * Block all memory allocation and lock the free list.
   */
  s = splimp();
  uvm_lock_fpageq();

  while ((m = list->tqh_first) != NULL) {
#ifdef DIAGNOSTIC
    if (m->pqflags & (PQ_ACTIVE|PQ_INACTIVE))
      panic("uvm_pglistfree: active/inactive page!");
#endif
    TAILQ_REMOVE(list, m, pageq);
    m->pqflags = PQ_FREE;
    TAILQ_INSERT_TAIL(&uvm.page_free, m, pageq);
    uvmexp.free++;
    STAT_DECR(uvm_pglistalloc_npages);
  }

  uvm_unlock_fpageq();
  splx(s);
}