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/* IBM_PROLOG_BEGIN_TAG */
/* This is an automatically generated prolog. */
/* */
/* $Source: src/include/kernel/pagemgr.H $ */
/* */
/* OpenPOWER HostBoot Project */
/* */
/* COPYRIGHT International Business Machines Corp. 2010,2014 */
/* */
/* Licensed under the Apache License, Version 2.0 (the "License"); */
/* you may not use this file except in compliance with the License. */
/* You may obtain a copy of the License at */
/* */
/* http://www.apache.org/licenses/LICENSE-2.0 */
/* */
/* Unless required by applicable law or agreed to in writing, software */
/* distributed under the License is distributed on an "AS IS" BASIS, */
/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or */
/* implied. See the License for the specific language governing */
/* permissions and limitations under the License. */
/* */
/* IBM_PROLOG_END_TAG */
#ifndef __KERNEL_PAGEMGR_H
#define __KERNEL_PAGEMGR_H
#include <stdint.h>
#include <limits.h>
#include <util/lockfree/stack.H>
#include <kernel/vmmmgr.H>
#include <builtins.h>
#include <kernel/console.H>
#include <util/align.H>
#include <sys/vfs.h>
/** @class PageManagerCore
* @brief Manages the allocation of memory pages
*/
class PageManagerCore
{
public:
enum
{
BUCKETS = 16,
};
struct page_t
{
page_t* next; //!< Next block of pages
page_t* prev; //!< Prev block of pages
page_t* key; //!< Key for pqueue
};
/**
* Default Constructor
*/
PageManagerCore()
: iv_available(0) {}
/**
* Add memory to the page manager
* @param[in] i_addr, The start address of the memory to add
* @param[in] i_pageCount, The number of pages to add
* @note i_addr must be on a page boundary
*/
void addMemory( size_t i_addr, size_t i_pageCount );
/**
* Destructor
*/
~PageManagerCore( void ) {}
/**
* Request page allocations
* @param[in] i_pageCount, The number of pages requested
* @return a pointer to the requested allocation | NULL
* if the request could not be satisfied.
*/
page_t * allocatePage( size_t i_pageCount );
/**
* Return page allocations to the page manager
* @param[in] i_page, pointer to the allocation
* @param[in] i_pageCount, the number of pages in the allocation
*/
void freePage( void * i_page, size_t i_pageCount );
/**
* Coalesce pages in the page manager (defrag)
*/
void coalesce( void );
/**
* Query the the current number of pages in the page manager
*/
ALWAYS_INLINE
size_t getFreePageCount() const { return iv_available; }
/**
* Get the start of memory after the code
*/
ALWAYS_INLINE uint64_t firstPageAddr( void ) const
{
return ALIGN_PAGE(VFS_LAST_ADDRESS);
}
private:
size_t iv_available; //!< free pages
Util::Lockfree::Stack<page_t> iv_heap[BUCKETS]; //!< The heap
/**
* Find a page of proper size
* @param[in] the Size
* @return a page ptr to a page of size pages
*/
page_t* pop_bucket(size_t);
/**
* Add a pages to the page manager
* @param[in] ptr to the allocation
* @param[in] The number of pages
*/
void push_bucket(page_t*, size_t);
};
/** @class PageManager
* @brief Manages the allocation of memory pages.
*/
class PageManager
{
public:
static void init();
/**
* Allocate pages
* @param[in] n, Requested allocation in pages
* @param[in] userspace - Request to allocate came from userspace
* @return pointer to requested memory
*/
static void* allocatePage(size_t n = 1, bool userspace = false);
/**
* Return pages to the pagemanager
* @param[in] ptr to storage to release
* @param[in] n, size in pages
*/
static void freePage(void*, size_t n = 1);
/**
* Query state for available memory
* @returns percent of pages available
*/
static uint64_t queryAvail();
/**
* Coalesce adjacent free memory blocks
* @pre This function can only be called from kernel space and
* requires that all other processes are quiesced
*/
static void coalesce( void );
/**
* Retrieve the number of available pages
* @returns Number of free pages
*/
static uint64_t availPages();
/**
* Add memory to the page manager
* @param[in] i_addr, The start address of the memory to add
* @param[in] i_pageCount, The number of pages to add
* @note i_addr must be on a page boundary
*/
static void addMemory(size_t i_addr, size_t i_pageCount);
enum
{
KERNEL_HEAP_RESERVED_PAGES = 4,
LOWMEM_NORM_LIMIT = 16,
LOWMEM_CRIT_LIMIT = 5,
};
static size_t cv_coalesce_count; //!< running coalesced counter
static size_t cv_low_page_count; //!< lowest page count
protected:
PageManager();
~PageManager() {};
private:
void _initialize();
void* _allocatePage(size_t,bool); //!< see allocatePage()
void _freePage(void*, size_t); //!< see freePage()
void _coalesce( void ); //!< see coalesce()
void _addMemory(size_t, size_t); //!< see addMemory()
/** see queryAvail() */
ALWAYS_INLINE uint64_t _queryAvail() const
{
return (100*iv_pagesAvail)/iv_pagesTotal;
}
ALWAYS_INLINE uint64_t firstPageAddr( void ) const
{
return iv_heap.firstPageAddr();
}
/** see availPages() */
ALWAYS_INLINE uint64_t _availPages() const
{
return iv_pagesAvail;
}
// Private data
uint64_t iv_pagesAvail; //!< free pages (for debug)
uint64_t iv_pagesTotal; //!< Total number o fpages
Spinlock iv_lock; //!< lock for allocating
PageManagerCore iv_heap; //!< Main heap
PageManagerCore iv_heapKernel; //!< kernel heap for out-of-mem
};
#endif
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