source: trunk/kernel/mm/kcm.c @ 567

/*
 * kcm.c - Per cluster Kernel Cache Manager implementation.
 *
 * Author  Ghassan Almaless (2008,2009,2010,2011,2012)
 *         Alain Greiner    (2016,2017,2018)
 *
 * Copyright (c) UPMC Sorbonne Universites
 *
 * This file is part of ALMOS-MKH.
 *
 * ALMOS-MKH is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2.0 of the License.
 *
 * ALMOS-MKH is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <kernel_config.h>
#include <hal_kernel_types.h>
#include <hal_special.h>
#include <busylock.h>
#include <list.h>
#include <printk.h>
#include <bits.h>
#include <ppm.h>
#include <thread.h>
#include <page.h>
#include <cluster.h>
#include <kmem.h>
#include <kcm.h>


//////////////////////////////////////////////////////////////////////////////////////
// This static function returns pointer on an allocated block from an active page.
// It returns NULL if no block available in selected page.
// It changes the page status if required.
//////////////////////////////////////////////////////////////////////////////////////
// @ kcm      : pointer on kcm allocator.
// @ kcm_page : pointer on active kcm page to use.
/////////////////////////////////////////////////////////////////////////////////////
static void * kcm_get_block( kcm_t      * kcm,
                             kcm_page_t * kcm_page )
{

#if DEBUG_KCM
uint32_t cycle = (uint32_t)hal_get_cycles();
if( DEBUG_KCM < cycle )
printk("\n[DBG] %s : thread %x enters for %s / page %x / count %d / active %d\n",
__FUNCTION__ , CURRENT_THREAD , kmem_type_str( kcm->type ) ,
(intptr_t)kcm_page , kcm_page->count , kcm_page->active );
#endif

        assert( kcm_page->active , "kcm_page should be active" );

        // get first block available
        int32_t index = bitmap_ffs( kcm_page->bitmap , kcm->blocks_nr );

        assert( (index != -1) , "kcm_page should not be full" );

        // allocate block
        bitmap_clear( kcm_page->bitmap , index );

        // increase kcm_page count
        kcm_page->count ++;

        // change the kcm_page to busy if no more free block in page
        if( kcm_page->count >= kcm->blocks_nr )
        {
                kcm_page->active = 0;
                list_unlink( &kcm_page->list);
                kcm->active_pages_nr --;

                list_add_first( &kcm->busy_root , &kcm_page->list);
                kcm->busy_pages_nr ++;
                kcm_page->busy = 1;
        }

        // compute return pointer
        void * ptr = (void *)((intptr_t)kcm_page + CONFIG_KCM_SLOT_SIZE
                     + (index * kcm->block_size) );

#if DEBUG_KCM
cycle = (uint32_t)hal_get_cycles();
if( DEBUG_KCM < cycle )
printk("\n[DBG] %s : thread %x exit / type  %s / ptr %x / page %x / count %d\n",
       __FUNCTION__ , CURRENT_THREAD , kmem_type_str( kcm->type ) , (intptr_t)ptr ,
(intptr_t)kcm_page , kcm_page->count );
#endif

        return ptr;
}

/////////////////////////////////////////////////////////////////////////////////////
// This static function releases a previously allocated block.
// It changes the kcm_page status if required.
/////////////////////////////////////////////////////////////////////////////////////
// @ kcm      : pointer on kcm allocator.
// @ kcm_page : pointer on kcm_page.
// @ ptr      : pointer on block to be released.
/////////////////////////////////////////////////////////////////////////////////////
static void kcm_put_block ( kcm_t      * kcm,
                            kcm_page_t * kcm_page,
                            void       * ptr )
{
        uint32_t     index;

        // compute block index from block pointer
        index = ((uint8_t *)ptr - (uint8_t *)kcm_page - CONFIG_KCM_SLOT_SIZE) / kcm->block_size;

        assert( !bitmap_state( kcm_page->bitmap , index ) , "page already freed" );
        assert( (kcm_page->count > 0) , "count already zero" );

        bitmap_set( kcm_page->bitmap , index );
        kcm_page->count --;

        // change the page to active if it was busy
        if( kcm_page->busy )
        {
                kcm_page->busy = 0;
                list_unlink( &kcm_page->list );
                kcm->busy_pages_nr --;

                list_add_last( &kcm->active_root, &kcm_page->list );
                kcm->active_pages_nr ++;
                kcm_page->active = 1;
        }

        // change the kcm_page to free if last block in active page
        if( (kcm_page->active) && (kcm_page->count == 0) )
        {
                kcm_page->active = 0;
                list_unlink( &kcm_page->list);
                kcm->active_pages_nr --;

                list_add_first( &kcm->free_root , &kcm_page->list);
                kcm->free_pages_nr ++;
        }
}

/////////////////////////////////////////////////////////////////////////////////////
// This static function allocates one page from PPM. It initializes
// the kcm_page descriptor, and introduces the new kcm_page into freelist.
/////////////////////////////////////////////////////////////////////////////////////
static error_t freelist_populate( kcm_t * kcm )
{
        page_t     * page;
        kcm_page_t * kcm_page;
        kmem_req_t   req;

        // get one page from local PPM
        req.type  = KMEM_PAGE;
        req.size  = 0;
        req.flags = AF_KERNEL;
        page = kmem_alloc( &req );

        if( page == NULL )
        {
                printk("\n[ERROR] in %s : failed to allocate page in cluster %d\n",
                       __FUNCTION__ , local_cxy );
                return ENOMEM;
        }

        // get page base address
        xptr_t base_xp = ppm_page2base( XPTR( local_cxy , page ) );
        kcm_page = (kcm_page_t *)GET_PTR( base_xp );

        // initialize KCM-page descriptor
        bitmap_set_range( kcm_page->bitmap , 0 , kcm->blocks_nr );

        kcm_page->busy          = 0;
        kcm_page->active        = 0;
        kcm_page->count      = 0;
        kcm_page->kcm           = kcm;
        kcm_page->page          = page;

        // introduce new page in free-list
        list_add_first( &kcm->free_root , &kcm_page->list );
        kcm->free_pages_nr ++;

        return 0;
}

/////////////////////////////////////////////////////////////////////////////////////
// This private function gets one KCM page from the KCM freelist.
// It populates the freelist if required.
/////////////////////////////////////////////////////////////////////////////////////
static kcm_page_t * freelist_get( kcm_t * kcm )
{
        error_t      error;
        kcm_page_t * kcm_page;

        // get a new page from PPM if freelist empty
        if( kcm->free_pages_nr == 0 )
        {
                error = freelist_populate( kcm );
                if( error ) return NULL;
        }

        // get first KCM page from freelist and unlink it
        kcm_page = LIST_FIRST( &kcm->free_root, kcm_page_t , list );
        list_unlink( &kcm_page->list );
        kcm->free_pages_nr --;

        return kcm_page;
}

//////////////////////////////
void kcm_init( kcm_t    * kcm,
                   uint32_t   type )
{
        // the kcm_page descriptor mut fit in the KCM slot
        assert( (sizeof(kcm_page_t) <= CONFIG_KCM_SLOT_SIZE) ,
                "KCM slot too small\n" );

        // initialize lock
        busylock_init( &kcm->lock , LOCK_KCM_STATE );

        // initialize KCM type
        kcm->type = type;

        // initialize KCM page lists
        kcm->free_pages_nr   = 0;
        kcm->busy_pages_nr   = 0;
        kcm->active_pages_nr = 0;
        list_root_init( &kcm->free_root );
        list_root_init( &kcm->busy_root );
        list_root_init( &kcm->active_root );

        // initialize block size
        uint32_t block_size = ARROUND_UP( kmem_type_size( type ) , CONFIG_KCM_SLOT_SIZE );
        kcm->block_size = block_size;

        // initialize number of blocks per page
        uint32_t  blocks_nr = (CONFIG_PPM_PAGE_SIZE - CONFIG_KCM_SLOT_SIZE) / block_size;
        kcm->blocks_nr = blocks_nr;
}

///////////////////////////////
void kcm_destroy( kcm_t * kcm )
{
        kcm_page_t   * kcm_page;
        list_entry_t * iter;

        // get KCM lock
        busylock_acquire( &kcm->lock );

        // release all free pages
        LIST_FOREACH( &kcm->free_root , iter )
        {
                kcm_page = (kcm_page_t *)LIST_ELEMENT( iter , kcm_page_t , list );
                list_unlink( iter );
                kcm->free_pages_nr --;
                ppm_free_pages( kcm_page->page );
        }

        // release all active pages
        LIST_FOREACH( &kcm->active_root , iter )
        {
                kcm_page = (kcm_page_t *)LIST_ELEMENT( iter , kcm_page_t , list );
                list_unlink( iter );
                kcm->free_pages_nr --;
                ppm_free_pages( kcm_page->page );
        }

        // release all busy pages
        LIST_FOREACH( &kcm->busy_root , iter )
        {
                kcm_page = (kcm_page_t *)LIST_ELEMENT( iter , kcm_page_t , list );
                list_unlink( iter );
                kcm->free_pages_nr --;
                ppm_free_pages( kcm_page->page );
        }

        // release KCM lock
        busylock_release( &kcm->lock );
}

///////////////////////////////
void * kcm_alloc( kcm_t * kcm )
{
        kcm_page_t * kcm_page;
        void       * ptr = NULL;   // pointer on block

        // get lock
        busylock_acquire( &kcm->lock );

        // get an active page
        if( list_is_empty( &kcm->active_root ) )  // no active page => get one
        {
                // get a page from free list
                kcm_page = freelist_get( kcm );

                if( kcm_page == NULL )
                {
                        busylock_release( &kcm->lock );
                        return NULL;
                }

                // insert page in active list
                list_add_first( &kcm->active_root , &kcm_page->list );
                kcm->active_pages_nr ++;
                kcm_page->active = 1;
        }
        else                                    // get first page from active list
        {
                // get page pointer from active list
                kcm_page = (kcm_page_t *)LIST_FIRST( &kcm->active_root , kcm_page_t , list );
        }

        // get a block from selected active page
        // cannot fail, as an active page cannot be full...
        ptr  = kcm_get_block( kcm , kcm_page );

        // release lock
        busylock_release( &kcm->lock );

        return ptr;
}

///////////////////////////
void kcm_free( void * ptr )
{
        kcm_page_t * kcm_page;
        kcm_t      * kcm;

        assert( (ptr != NULL) , "pointer cannot be NULL" );

        kcm_page = (kcm_page_t *)((intptr_t)ptr & ~CONFIG_PPM_PAGE_MASK);
        kcm      = kcm_page->kcm;

        // get lock
        busylock_acquire( &kcm->lock );

        // release block
        kcm_put_block( kcm , kcm_page , ptr );

        // release lock
        busylock_release( &kcm->lock );
}

////////////////////////////
void kcm_print (kcm_t * kcm)
{
        printk("*** KCM type = %s / free_pages = %d / busy_pages = %d / active_pages = %d\n",
               kmem_type_str( kcm->type ) ,
               kcm->free_pages_nr ,
               kcm->busy_pages_nr ,
               kcm->active_pages_nr );
}