Subversion Repositories HelenOS

/*

 * Copyright (C) 2001-2005 Jakub Jermar

 * Copyright (C) 2005 Sergey Bondari

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - 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.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.

 */

/**

 * @file    frame.c

 * @brief   Physical frame allocator.

 *

 * This file contains the physical frame allocator and memory zone management.

 * The frame allocator is built on top of the buddy allocator.

 *

 * @see buddy.c

 */

/*

 * Locking order

 *

 * In order to access particular zone, the process must first lock

 * the zones.lock, then lock the zone and then unlock the zones.lock.

 * This insures, that we can fiddle with the zones in runtime without

 * affecting the processes.

 *

 */

#include <typedefs.h>

#include <arch/types.h>

#include <mm/frame.h>

#include <mm/as.h>

#include <panic.h>

#include <debug.h>

#include <adt/list.h>

#include <synch/spinlock.h>

#include <arch/asm.h>

#include <arch.h>

#include <print.h>

#include <align.h>

#include <mm/slab.h>

#include <bitops.h>

#include <macros.h>

typedef struct {

    count_t refcount;   /**< tracking of shared frames  */

    __u8 buddy_order;   /**< buddy system block order */

    link_t buddy_link;  /**< link to the next free block inside one order */

    void *parent;           /**< If allocated by slab, this points there */

} frame_t;

typedef struct {

    SPINLOCK_DECLARE(lock); /**< this lock protects everything below */

    pfn_t base;     /**< frame_no of the first frame in the frames array */

    count_t count;          /**< Size of zone */

    frame_t *frames;    /**< array of frame_t structures in this zone */

    count_t free_count; /**< number of free frame_t structures */

    count_t busy_count; /**< number of busy frame_t structures */

    buddy_system_t * buddy_system; /**< buddy system for the zone */

    int flags;

} zone_t;

/*

 * The zoneinfo.lock must be locked when accessing zoneinfo structure.

 * Some of the attributes in zone_t structures are 'read-only'

 */

struct {

    SPINLOCK_DECLARE(lock);

    int count;

    zone_t *info[ZONES_MAX];

} zones;

/*********************************/

/* Helper functions */

static inline index_t frame_index(zone_t *zone, frame_t *frame)

{

    return (index_t)(frame - zone->frames);

}

static inline index_t frame_index_abs(zone_t *zone, frame_t *frame)

{

    return (index_t)(frame - zone->frames) + zone->base;

}

static inline int frame_index_valid(zone_t *zone, index_t index)

{

    return index >= 0 && index < zone->count;

}

/** Compute pfn_t from frame_t pointer & zone pointer */

static index_t make_frame_index(zone_t *zone, frame_t *frame)

{

    return frame - zone->frames;

}

/** Initialize frame structure

 *

 * Initialize frame structure.

 *

 * @param frame Frame structure to be initialized.

 */

static void frame_initialize(frame_t *frame)

{

    frame->refcount = 1;

    frame->buddy_order = 0;

}

/*************************************/

/* Zoneinfo functions */

/**

 * Insert-sort zone into zones list

 *

 * @param newzone New zone to be inserted into zone list

 * @return zone number on success, -1 on error

 */

static int zones_add_zone(zone_t *newzone)

{

    int i,j;

    ipl_t ipl;

    zone_t *z;

    ipl = interrupts_disable();

    spinlock_lock(&zones.lock);

    /* Try to merge */

    if (zones.count + 1 == ZONES_MAX)

        panic("Maximum zone(%d) count exceeded.", ZONES_MAX);

    for (i = 0; i < zones.count; i++) {

        /* Check for overflow */

        z = zones.info[i];

        if (overlaps(newzone->base,newzone->count,

                 z->base, z->count)) {

            printf("Zones overlap!\n");

            return -1;

        }

        if (newzone->base < z->base)

            break;

    }

    /* Move other zones up */

    for (j = i;j < zones.count; j++)

        zones.info[j + 1] = zones.info[j];

    zones.info[i] = newzone;

    zones.count++;

    spinlock_unlock(&zones.lock);

    interrupts_restore(ipl);

    return i;

}

/**

 * Try to find a zone where can we find the frame

 *

 * @param frame Frame number contained in zone

 * @param pzone If not null, it is used as zone hint. Zone index

 *              is filled into the variable on success.

 * @return Pointer to LOCKED zone containing frame

 *

 * Assume interrupts disable

 */

static zone_t * find_zone_and_lock(pfn_t frame, int *pzone)

{

    int i;

    int hint = pzone ? *pzone : 0;

    zone_t *z;

    spinlock_lock(&zones.lock);

    if (hint >= zones.count || hint < 0)

        hint = 0;

    i = hint;

    do {

        z = zones.info[i];

        spinlock_lock(&z->lock);

        if (z->base <= frame && z->base + z->count > frame) {

            spinlock_unlock(&zones.lock); /* Unlock the global lock */

            if (pzone)

                *pzone = i;

            return z;

        }

        spinlock_unlock(&z->lock);

        i++;

        if (i >= zones.count)

            i = 0;

    } while(i != hint);

    spinlock_unlock(&zones.lock);

    return NULL;

}

/** @return True if zone can allocate specified order */

static int zone_can_alloc(zone_t *z, __u8 order)

{

    return buddy_system_can_alloc(z->buddy_system, order);

}

/**

 * Find AND LOCK zone that can allocate order frames

 *

 * Assume interrupts are disabled!!

 *

 * @param order Size (2^order) of free space we are trying to find

 * @param pzone Pointer to preferred zone or NULL, on return contains zone number

 */

static zone_t * find_free_zone_lock(__u8 order, int *pzone)

{

    int i;

    zone_t *z;

    int hint = pzone ? *pzone : 0;

    spinlock_lock(&zones.lock);

    if (hint >= zones.count)

        hint = 0;

    i = hint;

    do {

        z = zones.info[i];

        spinlock_lock(&z->lock);

        /* Check if the zone has 2^order frames area available  */

        if (zone_can_alloc(z, order)) {

            spinlock_unlock(&zones.lock);

            if (pzone)

                *pzone = i;

            return z;

        }

        spinlock_unlock(&z->lock);

        if (++i >= zones.count)

            i = 0;

    } while(i != hint);

    spinlock_unlock(&zones.lock);

    return NULL;

}

/********************************************/

/* Buddy system functions */

/** Buddy system find_block implementation

 *

 * Find block that is parent of current list.

 * That means go to lower addresses, until such block is found

 *

 * @param order - Order of parent must be different then this parameter!!

 */

static link_t *zone_buddy_find_block(buddy_system_t *b, link_t *child,

                     __u8 order)

{

    frame_t * frame;

    zone_t * zone;

    index_t index;

    frame = list_get_instance(child, frame_t, buddy_link);

    zone = (zone_t *) b->data;

    index = frame_index(zone, frame);

    do {

        if (zone->frames[index].buddy_order != order) {

            return &zone->frames[index].buddy_link;

        }

    } while(index-- > 0);

    return NULL;

}

static void zone_buddy_print_id(buddy_system_t *b, link_t *block)

{

    frame_t * frame;

    zone_t * zone;

    index_t index;

    frame = list_get_instance(block, frame_t, buddy_link);

    zone = (zone_t *) b->data;

    index = frame_index(zone, frame);

    printf("%zd", index);

}                    

/** Buddy system find_buddy implementation

 *

 * @param b Buddy system.

 * @param block Block for which buddy should be found

 *

 * @return Buddy for given block if found

 */

static link_t * zone_buddy_find_buddy(buddy_system_t *b, link_t * block)

{

    frame_t * frame;

    zone_t * zone;

    index_t index;

    bool is_left, is_right;

    frame = list_get_instance(block, frame_t, buddy_link);

    zone = (zone_t *) b->data;

    ASSERT(IS_BUDDY_ORDER_OK(frame_index_abs(zone, frame), frame->buddy_order));

    is_left = IS_BUDDY_LEFT_BLOCK_ABS(zone, frame);

    is_right = IS_BUDDY_RIGHT_BLOCK_ABS(zone, frame);

    ASSERT(is_left ^ is_right);

    if (is_left) {

        index = (frame_index(zone, frame)) + (1 << frame->buddy_order);

    } else { // if (is_right)

        index = (frame_index(zone, frame)) - (1 << frame->buddy_order);

    }

    if (frame_index_valid(zone, index)) {

        if (zone->frames[index].buddy_order == frame->buddy_order &&

            zone->frames[index].refcount == 0) {

            return &zone->frames[index].buddy_link;

        }

    }

    return NULL;   

}

/** Buddy system bisect implementation

 *

 * @param b Buddy system.

 * @param block Block to bisect

 *

 * @return right block

 */

static link_t * zone_buddy_bisect(buddy_system_t *b, link_t * block) {

    frame_t * frame_l, * frame_r;

    frame_l = list_get_instance(block, frame_t, buddy_link);

    frame_r = (frame_l + (1 << (frame_l->buddy_order - 1)));

    return &frame_r->buddy_link;

}

/** Buddy system coalesce implementation

 *

 * @param b Buddy system.

 * @param block_1 First block

 * @param block_2 First block's buddy

 *

 * @return Coalesced block (actually block that represents lower address)

 */

static link_t * zone_buddy_coalesce(buddy_system_t *b, link_t * block_1,

                    link_t * block_2)

{

    frame_t *frame1, *frame2;

    frame1 = list_get_instance(block_1, frame_t, buddy_link);

    frame2 = list_get_instance(block_2, frame_t, buddy_link);

    return frame1 < frame2 ? block_1 : block_2;

}

/** Buddy system set_order implementation

 *

 * @param b Buddy system.

 * @param block Buddy system block

 * @param order Order to set

 */

static void zone_buddy_set_order(buddy_system_t *b, link_t * block, __u8 order) {

    frame_t * frame;

    frame = list_get_instance(block, frame_t, buddy_link);

    frame->buddy_order = order;

}

/** Buddy system get_order implementation

 *

 * @param b Buddy system.

 * @param block Buddy system block

 *

 * @return Order of block

 */

static __u8 zone_buddy_get_order(buddy_system_t *b, link_t * block) {

    frame_t * frame;

    frame = list_get_instance(block, frame_t, buddy_link);

    return frame->buddy_order;

}

/** Buddy system mark_busy implementation

 *

 * @param b Buddy system

 * @param block Buddy system block

 *

 */

static void zone_buddy_mark_busy(buddy_system_t *b, link_t * block) {

    frame_t * frame;

    frame = list_get_instance(block, frame_t, buddy_link);

    frame->refcount = 1;

}

/** Buddy system mark_available implementation

 *

 * @param b Buddy system

 * @param block Buddy system block

 *

 */

static void zone_buddy_mark_available(buddy_system_t *b, link_t * block) {

    frame_t * frame;

    frame = list_get_instance(block, frame_t, buddy_link);

    frame->refcount = 0;

}

static struct buddy_system_operations  zone_buddy_system_operations = {

    .find_buddy = zone_buddy_find_buddy,

    .bisect = zone_buddy_bisect,

    .coalesce = zone_buddy_coalesce,

    .set_order = zone_buddy_set_order,

    .get_order = zone_buddy_get_order,

    .mark_busy = zone_buddy_mark_busy,

    .mark_available = zone_buddy_mark_available,

    .find_block = zone_buddy_find_block,

    .print_id = zone_buddy_print_id

};

/*************************************/

/* Zone functions */

/** Allocate frame in particular zone

 *

 * Assume zone is locked

 * Panics if allocation is impossible.

 *

 * @param zone  Zone to allocate from.

 * @param order Allocate exactly 2^order frames.

 *

 * @return Frame index in zone

 *

 */

static pfn_t zone_frame_alloc(zone_t *zone, __u8 order)

{

    pfn_t v;

    link_t *tmp;

    frame_t *frame;

    /* Allocate frames from zone buddy system */

    tmp = buddy_system_alloc(zone->buddy_system, order);

    ASSERT(tmp);

    /* Update zone information. */

    zone->free_count -= (1 << order);

    zone->busy_count += (1 << order);

    /* Frame will be actually a first frame of the block. */

    frame = list_get_instance(tmp, frame_t, buddy_link);

    /* get frame address */

    v = make_frame_index(zone, frame);

    return v;

}

/** Free frame from zone

 *

 * Assume zone is locked

 *

 * @param zone Pointer to zone from which the frame is to be freed

 * @param frame_idx Frame index relative to zone

 */

static void zone_frame_free(zone_t *zone, index_t frame_idx)

{

    frame_t *frame;

    __u8 order;

    frame = &zone->frames[frame_idx];

    /* remember frame order */

    order = frame->buddy_order;

    ASSERT(frame->refcount);

    if (!--frame->refcount) {

        buddy_system_free(zone->buddy_system, &frame->buddy_link);

        /* Update zone information. */

        zone->free_count += (1 << order);

        zone->busy_count -= (1 << order);

    }

}

/** Return frame from zone */

static frame_t * zone_get_frame(zone_t *zone, index_t frame_idx)

{

    ASSERT(frame_idx < zone->count);

    return &zone->frames[frame_idx];

}

/** Mark frame in zone unavailable to allocation */

static void zone_mark_unavailable(zone_t *zone, index_t frame_idx)

{

    frame_t *frame;

    link_t *link;

    frame = zone_get_frame(zone, frame_idx);

    if (frame->refcount)

        return;

    link = buddy_system_alloc_block(zone->buddy_system,

                    &frame->buddy_link);

    ASSERT(link);

    zone->free_count--;

}

/**

 * Join 2 zones

 *

 * Expect zone_t *z to point to space at least zone_conf_size large

 *

 * Assume z1 & z2 are locked

 *

 * @param z Target zone structure pointer

 * @param z1 Zone to merge

 * @param z2 Zone to merge

 */

static void _zone_merge(zone_t *z, zone_t *z1, zone_t *z2)

{

    __u8 max_order;

    int i, z2idx;

    pfn_t frame_idx;

    frame_t *frame;

    ASSERT(!overlaps(z1->base,z1->count,z2->base,z2->count));

    ASSERT(z1->base < z2->base);

    spinlock_initialize(&z->lock, "zone_lock");

    z->base = z1->base;

    z->count = z2->base+z2->count - z1->base;

    z->flags = z1->flags & z2->flags;

    z->free_count = z1->free_count + z2->free_count;

    z->busy_count = z1->busy_count + z2->busy_count;

    max_order = fnzb(z->count);

    z->buddy_system = (buddy_system_t *)&z[1];

    buddy_system_create(z->buddy_system, max_order,

                &zone_buddy_system_operations,

                (void *) z);

    z->frames = (frame_t *)((void *)z->buddy_system+buddy_conf_size(max_order));

    for (i = 0; i < z->count; i++) {

        /* This marks all frames busy */

        frame_initialize(&z->frames[i]);

    }

    /* Copy frames from both zones to preserve full frame orders,

     * parents etc. Set all free frames with refcount=0 to 1, because

     * we add all free frames to buddy allocator later again, clear

     * order to 0. Don't set busy frames with refcount=0, as they

     * will not be reallocated during merge and it would make later

     * problems with allocation/free.

     */

    for (i=0; i<z1->count; i++)

        z->frames[i] = z1->frames[i];

    for (i=0; i < z2->count; i++) {

        z2idx = i + (z2->base - z1->base);

        z->frames[z2idx] = z2->frames[i];

    }

    i = 0;

    while (i < z->count) {

        if (z->frames[i].refcount) {

            /* skip busy frames */

            i += 1 << z->frames[i].buddy_order;

        } else { /* Free frames, set refcount=1 */

            /* All free frames have refcount=0, we need not

             * to check the order */

            z->frames[i].refcount = 1;

            z->frames[i].buddy_order = 0;

            i++;

        }

    }

    /* Add free blocks from the 2 original zones */

    while (zone_can_alloc(z1, 0)) {

        frame_idx = zone_frame_alloc(z1, 0);

        frame = &z->frames[frame_idx];

        frame->refcount = 0;

        buddy_system_free(z->buddy_system, &frame->buddy_link);

    }

    while (zone_can_alloc(z2, 0)) {

        frame_idx = zone_frame_alloc(z2, 0);

        frame = &z->frames[frame_idx + (z2->base-z1->base)];

        frame->refcount = 0;

        buddy_system_free(z->buddy_system, &frame->buddy_link);

    }

}

/** Return old configuration frames into the zone

 *

 * We have several cases

 * - the conf. data is outside of zone -> exit, shall we call frame_free??

 * - the conf. data was created by zone_create or

 *   updated with reduce_region -> free every frame

 *

 * @param newzone The actual zone where freeing should occur

 * @param oldzone Pointer to old zone configuration data that should

 *                be freed from new zone

 */

static void return_config_frames(zone_t *newzone, zone_t *oldzone)

{

    pfn_t pfn;

    frame_t *frame;

    count_t cframes;

    int i;

    pfn = ADDR2PFN((__address)KA2PA(oldzone));

    cframes = SIZE2FRAMES(zone_conf_size(oldzone->count));

    if (pfn < newzone->base || pfn >= newzone->base + newzone->count)

        return;

    frame = &newzone->frames[pfn - newzone->base];

    ASSERT(!frame->buddy_order);

    for (i=0; i < cframes; i++) {

        newzone->busy_count++;

        zone_frame_free(newzone, pfn+i-newzone->base);

    }

}

/** Reduce allocated block to count of order 0 frames

 *

 * The allocated block need 2^order frames of space. Reduce all frames

 * in block to order 0 and free the unneeded frames. This means, that

 * when freeing the previously allocated block starting with frame_idx,

 * you have to free every frame.

 *

 * @param zone

 * @param frame_idx Index to block

 * @param count Allocated space in block

 */

static void zone_reduce_region(zone_t *zone, pfn_t frame_idx, count_t count)

{

    count_t i;

    __u8 order;

    frame_t *frame;

    ASSERT(frame_idx+count < zone->count);

    order = zone->frames[frame_idx].buddy_order;

    ASSERT((1 << order) >= count);

    /* Reduce all blocks to order 0 */

    for (i=0; i < (1 << order); i++) {

        frame = &zone->frames[i + frame_idx];

        frame->buddy_order = 0;

        if (! frame->refcount)

            frame->refcount = 1;

        ASSERT(frame->refcount == 1);

    }

    /* Free unneeded frames */

    for (i=count; i < (1 << order); i++) {

        zone_frame_free(zone, i + frame_idx);

    }

}

/** Merge zones z1 and z2

 *

 * - the zones must be 2 zones with no zone existing in between,

 *   which means that z2 = z1+1

 *

 * - When you create a new zone, the frame allocator configuration does

 *   not to be 2^order size. Once the allocator is running it is no longer

 *   possible, merged configuration data occupies more space :-/

 */

void zone_merge(int z1, int z2)

{

    ipl_t ipl;

    zone_t *zone1, *zone2, *newzone;

    int cframes;

    __u8 order;

    int i;

    pfn_t pfn;

    ipl = interrupts_disable();

    spinlock_lock(&zones.lock);

    if (z1 < 0 || z1 >= zones.count || z2 < 0 || z2 >= zones.count)

        goto errout;

    /* We can join only 2 zones with none existing inbetween */

    if (z2-z1 != 1)

        goto errout;

    zone1 = zones.info[z1];

    zone2 = zones.info[z2];

    spinlock_lock(&zone1->lock);

    spinlock_lock(&zone2->lock);

    cframes = SIZE2FRAMES(zone_conf_size(zone2->base+zone2->count-zone1->base));

    if (cframes == 1)

        order = 0;

    else

        order = fnzb(cframes - 1) + 1;

    /* Allocate zonedata inside one of the zones */

    if (zone_can_alloc(zone1, order))

        pfn = zone1->base + zone_frame_alloc(zone1, order);

    else if (zone_can_alloc(zone2, order))

        pfn = zone2->base + zone_frame_alloc(zone2, order);

    else

        goto errout2;

    newzone = (zone_t *)PA2KA(PFN2ADDR(pfn));

    _zone_merge(newzone, zone1, zone2);

    /* Free unneeded config frames */

    zone_reduce_region(newzone, pfn - newzone->base,  cframes);

    /* Subtract zone information from busy frames */

    newzone->busy_count -= cframes;

    /* Replace existing zones in zoneinfo list */

    zones.info[z1] = newzone;

    for (i = z2 + 1; i < zones.count; i++)

        zones.info[i - 1] = zones.info[i];

    zones.count--;

    /* Free old zone information */

    return_config_frames(newzone, zone1);

    return_config_frames(newzone, zone2);

errout2:

    /* Nobody is allowed to enter to zone, so we are safe

     * to touch the spinlocks last time */

    spinlock_unlock(&zone1->lock);

    spinlock_unlock(&zone2->lock);

errout:

    spinlock_unlock(&zones.lock);

    interrupts_restore(ipl);

}

/**

 * Merge all zones into one big zone

 *

 * It is reasonable to do this on systems whose bios reports parts in chunks,

 * so that we could have 1 zone (it's faster).

 */

void zone_merge_all(void)

{

    int count = zones.count;

    while (zones.count > 1 && --count) {

        zone_merge(0,1);

        break;

    }

}

/** Create frame zone

 *

 * Create new frame zone.

 *

 * @param start Physical address of the first frame within the zone.

 * @param count Count of frames in zone

 * @param z Address of configuration information of zone

 * @param flags Zone flags.

 *

 * @return Initialized zone.

 */

static void zone_construct(pfn_t start, count_t count, zone_t *z, int flags)

{

    int i;

    __u8 max_order;

    spinlock_initialize(&z->lock, "zone_lock");

    z->base = start;

    z->count = count;

    z->flags = flags;

    z->free_count = count;

    z->busy_count = 0;

    /*

     * Compute order for buddy system, initialize

     */

    max_order = fnzb(count);

    z->buddy_system = (buddy_system_t *)&z[1];

    buddy_system_create(z->buddy_system, max_order,

                &zone_buddy_system_operations,

                (void *) z);