/* -*- Mode: C; c-basic-offset:4 ; -*- */
/**
  * Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
  *                         University Research and Technology
  *                         Corporation.  All rights reserved.
  * Copyright (c) 2004-2007 The University of Tennessee and The University
  *                         of Tennessee Research Foundation.  All rights
  *                         reserved.
  * Copyright (c) 2004-2005 High Performance Computing Center Stuttgart, 
  *                         University of Stuttgart.  All rights reserved.
  * Copyright (c) 2004-2005 The Regents of the University of California.
  *                         All rights reserved.
  *
  * Copyright (c) 2006      Voltaire. All rights reserved.
  * Copyright (c) 2007      Mellanox Technologies. All rights reserved.
  *
  * $COPYRIGHT$
  * 
  * Additional copyrights may follow
  * 
  * $HEADER$
  */
/**
  * @file
  * Description of the Registration Cache framework
  */

#include "ompi_config.h"

#include "opal/mca/mca.h"
#include "rcache_vma_tree.h"

OBJ_CLASS_INSTANCE(mca_rcache_vma_reg_list_item_t, opal_list_item_t, NULL, NULL);

static void mca_rcache_vma_construct(opal_object_t *object)
{
    mca_rcache_vma_t *vma = (mca_rcache_vma_t*)object;
    OBJ_CONSTRUCT(&vma->reg_list, opal_list_t);
}

static void mca_rcache_vma_destruct(opal_object_t *object)
{
    mca_rcache_vma_t *vma = (mca_rcache_vma_t*)object;
    OBJ_DESTRUCT(&vma->reg_list);
}

OBJ_CLASS_INSTANCE(mca_rcache_vma_t, ompi_free_list_item_t,
        mca_rcache_vma_construct, mca_rcache_vma_destruct); 


/**
 * Function for the red black tree to compare 2 keys
 *
 * @param key1 a pointer to the 1st key
 * @param key2 a pointer to the second key
 *
 * @retval -1 if key1 is below key2
 * @retval 1 if key 1 is above key2
 * @retval 0 if the keys are the same
 */

static int mca_rcache_vma_tree_node_compare(void *key1, void *key2)
{
    mca_rcache_vma_t *vma1 = (mca_rcache_vma_t*)key1, 
                     *vma2 = (mca_rcache_vma_t*)key2;

    if(vma1->start < vma2->start)
        return -1;
    if(vma1->start > vma2->start)
        return 1;

    return 0;
}

static int mca_rcache_vma_tree_node_compare_search(void *key1, void *key2)
{
    mca_rcache_vma_t *vma = (mca_rcache_vma_t*)key2;
    uintptr_t addr = (uintptr_t)key1;

    if(vma->end < addr)
        return 1;
    if(vma->start <= addr)
        return 0;

    return -1;
}

static int mca_rcache_vma_tree_node_compare_closest(void *key1, void *key2)
{
    mca_rcache_vma_t *vma = (mca_rcache_vma_t*)key2, *prev_vma;
    uintptr_t addr = (uintptr_t)key1;

    if(vma->end < addr)
       return 1;
    if(vma->start <= addr)
        return 0;
    prev_vma = (mca_rcache_vma_t *)opal_list_get_prev(&vma->super.super);
    if(prev_vma == (mca_rcache_vma_t *)opal_list_get_end(&vma->rcache->vma_list)
            || prev_vma->end < addr)
        return 0;

    return -1;
}

static inline mca_rcache_vma_t *mca_rcache_vma_new(
        mca_rcache_vma_module_t *vma_rcache, uintptr_t start, uintptr_t end)
{
    int rc;
    mca_rcache_vma_t *vma = OBJ_NEW(mca_rcache_vma_t);

    if(NULL == vma)
        return NULL;

    vma->start = start;
    vma->end = end;
    vma->rcache = vma_rcache;

    rc = ompi_rb_tree_insert(&vma_rcache->rb_tree, vma, vma);

    return vma;
}

static inline void mca_rcache_vma_destroy(mca_rcache_vma_t *vma)
{
    opal_list_item_t *item;

    while ((item = opal_list_remove_first(&vma->reg_list)))
        OBJ_RELEASE(item);

    OBJ_RELEASE(vma);
}

static inline int mca_rcache_vma_compare_regs(
        mca_mpool_base_registration_t *reg1,
        mca_mpool_base_registration_t *reg2)
{
    /* persisten registration are on top */
    if((reg1->flags & MCA_MPOOL_FLAGS_PERSIST) &&
            !(reg2->flags & MCA_MPOOL_FLAGS_PERSIST))
        return 1;

    if(!(reg1->flags & MCA_MPOOL_FLAGS_PERSIST) &&
            (reg2->flags & MCA_MPOOL_FLAGS_PERSIST))
        return -1;

    if (reg1->bound != reg2->bound)
        return (int)(reg1->bound - reg2->bound);

    /* tie breaker */
    return (int)((uintptr_t)reg1 - (uintptr_t)reg2);
}

static inline int mca_rcache_vma_add_reg(mca_rcache_vma_t *vma,
        mca_mpool_base_registration_t *reg)
{
    opal_list_item_t *i;
    mca_rcache_vma_reg_list_item_t *item, *entry;

    entry = OBJ_NEW(mca_rcache_vma_reg_list_item_t);

    if(!entry)
        return -1;

    entry->reg = reg;
    
    for(i = opal_list_get_first(&vma->reg_list);
            i != opal_list_get_end(&vma->reg_list);
            i = opal_list_get_next(i)) {
        item = (mca_rcache_vma_reg_list_item_t*)i;

        if(mca_rcache_vma_compare_regs(item->reg, reg) > 0)
            continue;

        opal_list_insert_pos(&vma->reg_list, &item->super, &entry->super);
        return 0;
    }
    opal_list_append(&vma->reg_list, &entry->super);
    return 0;
}

static inline void mca_rcache_vma_remove_reg(mca_rcache_vma_t *vma,
        mca_mpool_base_registration_t *reg)
{
    opal_list_item_t *i;
    mca_rcache_vma_reg_list_item_t *item;

    for(i = opal_list_get_first(&vma->reg_list);
            i != opal_list_get_end(&vma->reg_list);
            i = opal_list_get_next(i)) {
        item = (mca_rcache_vma_reg_list_item_t*)i;

        if(item->reg == reg) {
            opal_list_remove_item(&vma->reg_list, &item->super);
            OBJ_RELEASE(item);
            break;
        }
    }
}

static inline int mca_rcache_vma_copy_reg_list(mca_rcache_vma_t *to,
        mca_rcache_vma_t *from)
{
    opal_list_item_t *i;
    mca_rcache_vma_reg_list_item_t *item_f, *item_t;
    for(i = opal_list_get_first(&from->reg_list);
            i != opal_list_get_end(&from->reg_list);
            i = opal_list_get_next(i)) {
        item_f = (mca_rcache_vma_reg_list_item_t*)i;
        item_t = OBJ_NEW(mca_rcache_vma_reg_list_item_t);

        if(NULL == item_t)
            return 0;

        item_t->reg = item_f->reg;

        opal_list_append(&to->reg_list, &item_t->super);
    }

    return OMPI_SUCCESS;
}

/* returns 1 iff two lists contain the same entries */
static inline int mca_rcache_vma_compare_reg_lists(mca_rcache_vma_t *vma1,
        mca_rcache_vma_t *vma2)
{
    mca_rcache_vma_reg_list_item_t *i1, *i2;

    if (!vma1 || !vma2)
        return 0;

    if(opal_list_get_size(&vma1->reg_list) !=
            opal_list_get_size(&vma2->reg_list))
        return 0;

    i1 = (mca_rcache_vma_reg_list_item_t*)opal_list_get_first(&vma1->reg_list);
    i2 = (mca_rcache_vma_reg_list_item_t*)opal_list_get_first(&vma2->reg_list);

    do {
        if(i1  == (mca_rcache_vma_reg_list_item_t*)opal_list_get_end(&vma1->reg_list) || 
            i2 == (mca_rcache_vma_reg_list_item_t*)opal_list_get_end(&vma2->reg_list))
            return 1;

        if(i1->reg != i2->reg)
            break;

        i1 = (mca_rcache_vma_reg_list_item_t*)opal_list_get_next(i1);
        i2 = (mca_rcache_vma_reg_list_item_t*)opal_list_get_next(i2);
    } while(1);

    return 0;
}

int mca_rcache_vma_tree_init(mca_rcache_vma_module_t* rcache)
{ 
    OBJ_CONSTRUCT(&rcache->rb_tree, ompi_rb_tree_t);
    OBJ_CONSTRUCT(&rcache->vma_list, opal_list_t); 
    rcache->reg_cur_cache_size = 0;
    return ompi_rb_tree_init(&rcache->rb_tree, 
                             mca_rcache_vma_tree_node_compare);
}

mca_mpool_base_registration_t *mca_rcache_vma_tree_find(
        mca_rcache_vma_module_t* vma_rcache, unsigned char *base,
        unsigned char *bound)
{
    mca_rcache_vma_t *vma;
    mca_rcache_vma_reg_list_item_t *item;

    vma = (mca_rcache_vma_t*)ompi_rb_tree_find_with(&vma_rcache->rb_tree, base, 
            mca_rcache_vma_tree_node_compare_search);

    if(!vma)
        return NULL;
    
    for(item = (mca_rcache_vma_reg_list_item_t*)
            opal_list_get_first(&vma->reg_list);
            item != (mca_rcache_vma_reg_list_item_t*)
            opal_list_get_end(&vma->reg_list);
            item = (mca_rcache_vma_reg_list_item_t*)
            opal_list_get_next(item)) {
        if(item->reg->flags & MCA_MPOOL_FLAGS_INVALID)
            continue;
        if(item->reg->bound >= bound)
            return item->reg;
        if(!(item->reg->flags & MCA_MPOOL_FLAGS_PERSIST))
            break;
    }

    return NULL;
}

static inline bool is_reg_in_array(mca_mpool_base_registration_t **regs,
        int cnt, mca_mpool_base_registration_t *p)
{
    int i;

    for(i = 0; i < cnt; i++) {
        if(regs[i] == p)
            return true;
    }

    return false;
}

int mca_rcache_vma_tree_find_all(
        mca_rcache_vma_module_t *vma_rcache, unsigned char *base,
        unsigned char *bound, mca_mpool_base_registration_t **regs,
        int reg_cnt)
{
    int cnt = 0;

    if(opal_list_get_size(&vma_rcache->vma_list) == 0)
        return cnt;

    do {
        mca_rcache_vma_t *vma;
        opal_list_item_t *item;
        vma = (mca_rcache_vma_t*)
            ompi_rb_tree_find_with(&vma_rcache->rb_tree, base,
                mca_rcache_vma_tree_node_compare_closest);

        if(NULL == vma) {
            /* base is bigger than any registered memory */
            break;
        }

        if(base < (unsigned char*)vma->start) {
            base = (unsigned char*)vma->start;
            continue;
        }

        for(item = opal_list_get_first(&vma->reg_list);
                item != opal_list_get_end(&vma->reg_list);
                item = opal_list_get_next(item)) {
            mca_rcache_vma_reg_list_item_t *vma_item;
            vma_item = (mca_rcache_vma_reg_list_item_t*)item;
            if((vma_item->reg->flags & MCA_MPOOL_FLAGS_INVALID) ||
                    is_reg_in_array(regs, cnt, vma_item->reg)) {
                continue;
            }
            regs[cnt++] = vma_item->reg;
            if(cnt == reg_cnt)
                return cnt; /* no space left in the provided array */
        }

        base = (unsigned char *)vma->end + 1;
    } while(bound >= base);

    return cnt;
}

static inline int mca_rcache_vma_can_insert(
        mca_rcache_vma_module_t *vma_rcache, size_t nbytes, size_t limit)
{
    if(0 == limit)
        return 1;

    if(vma_rcache->reg_cur_cache_size + nbytes <= limit)
        return 1;

    return 0;
}

static inline void mca_rcache_vma_update_byte_count(
        mca_rcache_vma_module_t* vma_rcache,
        size_t nbytes)
{
    vma_rcache->reg_cur_cache_size += nbytes;
}
        
int mca_rcache_vma_tree_insert(mca_rcache_vma_module_t* vma_rcache,
        mca_mpool_base_registration_t* reg, size_t limit)
{
    mca_rcache_vma_t *i;
    uintptr_t begin = (uintptr_t)reg->base, end = (uintptr_t)reg->bound;

    i = (mca_rcache_vma_t*)ompi_rb_tree_find_with(&vma_rcache->rb_tree,
            (void*)begin, mca_rcache_vma_tree_node_compare_closest);

    if(!i)
        i = (mca_rcache_vma_t*)opal_list_get_end(&vma_rcache->vma_list);

    while (begin <= end) {
        mca_rcache_vma_t *vma;

        if((mca_rcache_vma_t*)opal_list_get_end(&vma_rcache->vma_list) == i) {
            vma = NULL;
            if(mca_rcache_vma_can_insert(vma_rcache, end - begin + 1, limit))
                vma = mca_rcache_vma_new(vma_rcache, begin, end);

            if(!vma)
                goto remove;

            mca_rcache_vma_update_byte_count(vma_rcache, end - begin + 1);
           
            opal_list_append(&vma_rcache->vma_list, &vma->super);
            begin = vma->end + 1;
            mca_rcache_vma_add_reg(vma, reg);
        } else if(i->start > begin) {
            uintptr_t tend = (i->start <= end)?(i->start - 1):end;
            vma = NULL;
            if(mca_rcache_vma_can_insert(vma_rcache, tend - begin + 1, limit))
                vma = mca_rcache_vma_new(vma_rcache, begin, tend);

            if(!vma)
                goto remove;

            mca_rcache_vma_update_byte_count(vma_rcache, tend - begin + 1);

            /* insert before */
            opal_list_insert_pos(&vma_rcache->vma_list, &i->super, &vma->super);
            i = vma;
            begin = vma->end + 1;
            mca_rcache_vma_add_reg(vma, reg);
        } else if(i->start == begin) {
            if (i->end > end) {
                vma = mca_rcache_vma_new(vma_rcache, end+1, i->end);
                if(!vma)
                    goto remove;

                i->end = end;

                mca_rcache_vma_copy_reg_list(vma, i);

                /* add after */
                opal_list_insert_pos(&vma_rcache->vma_list,
                        opal_list_get_next(&i->super),
                        &vma->super);
                mca_rcache_vma_add_reg(i, reg);
                begin = end + 1;
            } else {
                mca_rcache_vma_add_reg(i, reg);
                begin = i->end + 1;
            }
        } else {
                vma = mca_rcache_vma_new(vma_rcache, begin, i->end);

                if(!vma)
                    goto remove;

                i->end = begin - 1;

                mca_rcache_vma_copy_reg_list(vma, i);

                /* add after */
                opal_list_insert_pos(&vma_rcache->vma_list,
                        opal_list_get_next(&i->super),
                        &vma->super);
        }

        i = (mca_rcache_vma_t*)opal_list_get_next(&i->super);
    }

    return OMPI_SUCCESS;

remove:
    mca_rcache_vma_tree_delete(vma_rcache, reg);
    return OMPI_ERR_TEMP_OUT_OF_RESOURCE;
}

/**
 * Function to remove previously memory from the tree without freeing it
 *
 * @param base pointer to the memory to free
 *
 * @retval OMPI_SUCCESS
 * @retval OMPI_ERR_BAD_PARAM if the passed base pointer was invalid
 */
int mca_rcache_vma_tree_delete(mca_rcache_vma_module_t* vma_rcache, 
                          mca_mpool_base_registration_t* reg)
{
    mca_rcache_vma_t *vma;

    vma = (mca_rcache_vma_t*)ompi_rb_tree_find_with(&vma_rcache->rb_tree, reg->base, 
            mca_rcache_vma_tree_node_compare_search);

    if(!vma)
        return OMPI_ERROR;

    while(vma != (mca_rcache_vma_t*)opal_list_get_end(&vma_rcache->vma_list)
            && vma->start <= (uintptr_t)reg->bound) {
        mca_rcache_vma_remove_reg(vma, reg);
        
        if(opal_list_is_empty(&vma->reg_list)) {
            mca_rcache_vma_t *next = (mca_rcache_vma_t*)opal_list_get_next(&vma->super);
            ompi_rb_tree_delete(&vma_rcache->rb_tree, vma);
            mca_rcache_vma_update_byte_count(vma_rcache,
                    vma->start - vma->end - 1);
            opal_list_remove_item(&vma_rcache->vma_list, &vma->super);
            mca_rcache_vma_destroy(vma);
            vma = next;
        } else {
            int merged;

            do {
                mca_rcache_vma_t *prev = NULL, *next = NULL;
                if(opal_list_get_begin(&vma_rcache->vma_list) != 
                        opal_list_get_prev(vma))
                    prev = (mca_rcache_vma_t*)opal_list_get_prev(vma);
                merged = 0;

                if(prev && vma->start == prev->end + 1 &&
                        mca_rcache_vma_compare_reg_lists(vma, prev)) {
                    prev->end = vma->end;
                    opal_list_remove_item(&vma_rcache->vma_list, &vma->super);
                    ompi_rb_tree_delete(&vma_rcache->rb_tree, vma);
                    mca_rcache_vma_destroy(vma);
                    vma = prev;
                    merged = 1;
                }
                if(opal_list_get_end(&vma_rcache->vma_list) != 
                        opal_list_get_next(vma))
                    next = (mca_rcache_vma_t*)opal_list_get_next(vma);

                if(next && vma->end + 1 == next->start &&
                        mca_rcache_vma_compare_reg_lists(vma, next)) {
                    vma->end = next->end;
                    opal_list_remove_item(&vma_rcache->vma_list, &next->super);
                    ompi_rb_tree_delete(&vma_rcache->rb_tree, next);
                    mca_rcache_vma_destroy(next);
                    merged = 1;
                }
            } while(merged);
            vma = (mca_rcache_vma_t*)opal_list_get_next(vma);
        }
    }
    return 0;
}