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[PATCH] change gen_pool allocator to not touch managed memory

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Modify the gen_pool allocator (lib/genalloc.c) to utilize a bitmap scheme
instead of the buddy scheme.  The purpose of this change is to eliminate
the touching of the actual memory being allocated.

Since the change modifies the interface, a change to the uncached allocator
(arch/ia64/kernel/uncached.c) is also required.

Both Andrey Volkov and Jes Sorenson have expressed a desire that the
gen_pool allocator not write to the memory being managed. See the
following:

  http://marc.theaimsgroup.com/?l=linux-kernel&m=113518602713125&w=2
  http://marc.theaimsgroup.com/?l=linux-kernel&m=113533568827916&w=2

Signed-off-by: Dean Nelson <dcn@sgi.com>
Cc: Andrey Volkov <avolkov@varma-el.com>
Acked-by: Jes Sorensen <jes@trained-monkey.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Dean Nelson 2006-06-23 02:03:21 -07:00 committed by Linus Torvalds
parent 833423143c
commit 929f97276b
4 changed files with 252 additions and 261 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

200
arch/ia64/kernel/uncached.c
View File

@ -1,5 +1,5 @@
/*
* Copyright (C) 2001-2005 Silicon Graphics, Inc. All rights reserved.
* Copyright (C) 2001-2006 Silicon Graphics, Inc. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of version 2 of the GNU General Public License
@ -29,15 +29,8 @@
#include <asm/tlbflush.h>
#include <asm/sn/arch.h>
#define DEBUG 0
#if DEBUG
#define dprintk printk
#else
#define dprintk(x...) do { } while (0)
#endif
void __init efi_memmap_walk_uc (efi_freemem_callback_t callback);
extern void __init efi_memmap_walk_uc(efi_freemem_callback_t, void *);
#define MAX_UNCACHED_GRANULES 5
static int allocated_granules;
@ -60,6 +53,7 @@ static void uncached_ipi_visibility(void *data)
static void uncached_ipi_mc_drain(void *data)
{
int status;
status = ia64_pal_mc_drain();
if (status)
printk(KERN_WARNING "ia64_pal_mc_drain() failed with %i on "
@ -67,30 +61,35 @@ static void uncached_ipi_mc_drain(void *data)
}
static unsigned long
uncached_get_new_chunk(struct gen_pool *poolp)
/*
* Add a new chunk of uncached memory pages to the specified pool.
*
* @pool: pool to add new chunk of uncached memory to
* @nid: node id of node to allocate memory from, or -1
*
* This is accomplished by first allocating a granule of cached memory pages
* and then converting them to uncached memory pages.
*/
static int uncached_add_chunk(struct gen_pool *pool, int nid)
{
struct page *page;
void *tmp;
int status, i;
unsigned long addr, node;
unsigned long c_addr, uc_addr;
if (allocated_granules >= MAX_UNCACHED_GRANULES)
return 0;
return -1;
node = poolp->private;
page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO,
/* attempt to allocate a granule's worth of cached memory pages */
page = alloc_pages_node(nid, GFP_KERNEL | __GFP_ZERO,
IA64_GRANULE_SHIFT-PAGE_SHIFT);
dprintk(KERN_INFO "get_new_chunk page %p, addr %lx\n",
page, (unsigned long)(page-vmem_map) << PAGE_SHIFT);
/*
* Do magic if no mem on local node! XXX
*/
if (!page)
return 0;
tmp = page_address(page);
return -1;
/* convert the memory pages from cached to uncached */
c_addr = (unsigned long)page_address(page);
uc_addr = c_addr - PAGE_OFFSET + __IA64_UNCACHED_OFFSET;
/*
* There's a small race here where it's possible for someone to
@ -100,76 +99,90 @@ uncached_get_new_chunk(struct gen_pool *poolp)
for (i = 0; i < (IA64_GRANULE_SIZE / PAGE_SIZE); i++)
SetPageUncached(&page[i]);
flush_tlb_kernel_range(tmp, tmp + IA64_GRANULE_SIZE);
flush_tlb_kernel_range(uc_addr, uc_adddr + IA64_GRANULE_SIZE);
status = ia64_pal_prefetch_visibility(PAL_VISIBILITY_PHYSICAL);
dprintk(KERN_INFO "pal_prefetch_visibility() returns %i on cpu %i\n",
status, raw_smp_processor_id());
if (!status) {
status = smp_call_function(uncached_ipi_visibility, NULL, 0, 1);
if (status)
printk(KERN_WARNING "smp_call_function failed for "
"uncached_ipi_visibility! (%i)\n", status);
goto failed;
}
preempt_disable();
if (ia64_platform_is("sn2"))
sn_flush_all_caches((unsigned long)tmp, IA64_GRANULE_SIZE);
sn_flush_all_caches(uc_addr, IA64_GRANULE_SIZE);
else
flush_icache_range((unsigned long)tmp,
(unsigned long)tmp+IA64_GRANULE_SIZE);
flush_icache_range(uc_addr, uc_addr + IA64_GRANULE_SIZE);
/* flush the just introduced uncached translation from the TLB */
local_flush_tlb_all();
preempt_enable();
ia64_pal_mc_drain();
status = smp_call_function(uncached_ipi_mc_drain, NULL, 0, 1);
if (status)
printk(KERN_WARNING "smp_call_function failed for "
"uncached_ipi_mc_drain! (%i)\n", status);
goto failed;
addr = (unsigned long)tmp - PAGE_OFFSET + __IA64_UNCACHED_OFFSET;
/*
* The chunk of memory pages has been converted to uncached so now we
* can add it to the pool.
*/
status = gen_pool_add(pool, uc_addr, IA64_GRANULE_SIZE, nid);
if (status)
goto failed;
allocated_granules++;
return addr;
return 0;
/* failed to convert or add the chunk so give it back to the kernel */
failed:
for (i = 0; i < (IA64_GRANULE_SIZE / PAGE_SIZE); i++)
ClearPageUncached(&page[i]);
free_pages(c_addr, IA64_GRANULE_SHIFT-PAGE_SHIFT);
return -1;
}
/*
* uncached_alloc_page
*
* @starting_nid: node id of node to start with, or -1
*
* Allocate 1 uncached page. Allocates on the requested node. If no
* uncached pages are available on the requested node, roundrobin starting
* with higher nodes.
* with the next higher node.
*/
unsigned long
uncached_alloc_page(int nid)
unsigned long uncached_alloc_page(int starting_nid)
{
unsigned long maddr;
unsigned long uc_addr;
struct gen_pool *pool;
int nid;
maddr = gen_pool_alloc(uncached_pool[nid], PAGE_SIZE);
if (unlikely(starting_nid >= MAX_NUMNODES))
return 0;
dprintk(KERN_DEBUG "uncached_alloc_page returns %lx on node %i\n",
maddr, nid);
if (starting_nid < 0)
starting_nid = numa_node_id();
nid = starting_nid;
/*
* If no memory is availble on our local node, try the
* remaining nodes in the system.
*/
if (!maddr) {
int i;
do {
if (!node_online(nid))
continue;
pool = uncached_pool[nid];
if (pool == NULL)
continue;
do {
uc_addr = gen_pool_alloc(pool, PAGE_SIZE);
if (uc_addr != 0)
return uc_addr;
} while (uncached_add_chunk(pool, nid) == 0);
for (i = MAX_NUMNODES - 1; i >= 0; i--) {
if (i == nid || !node_online(i))
continue;
maddr = gen_pool_alloc(uncached_pool[i], PAGE_SIZE);
dprintk(KERN_DEBUG "uncached_alloc_page alternate search "
"returns %lx on node %i\n", maddr, i);
if (maddr) {
break;
}
}
}
} while ((nid = (nid + 1) % MAX_NUMNODES) != starting_nid);
return maddr;
return 0;
}
EXPORT_SYMBOL(uncached_alloc_page);
@ -177,21 +190,22 @@ EXPORT_SYMBOL(uncached_alloc_page);
/*
* uncached_free_page
*
* @uc_addr: uncached address of page to free
*
* Free a single uncached page.
*/
void
uncached_free_page(unsigned long maddr)
void uncached_free_page(unsigned long uc_addr)
{
int node;
int nid = paddr_to_nid(uc_addr - __IA64_UNCACHED_OFFSET);
struct gen_pool *pool = uncached_pool[nid];
node = paddr_to_nid(maddr - __IA64_UNCACHED_OFFSET);
if (unlikely(pool == NULL))
return;
dprintk(KERN_DEBUG "uncached_free_page(%lx) on node %i\n", maddr, node);
if ((uc_addr & (0XFUL << 60)) != __IA64_UNCACHED_OFFSET)
panic("uncached_free_page invalid address %lx\n", uc_addr);
if ((maddr & (0XFUL << 60)) != __IA64_UNCACHED_OFFSET)
panic("uncached_free_page invalid address %lx\n", maddr);
gen_pool_free(uncached_pool[node], maddr, PAGE_SIZE);
gen_pool_free(pool, uc_addr, PAGE_SIZE);
}
EXPORT_SYMBOL(uncached_free_page);
@ -199,43 +213,39 @@ EXPORT_SYMBOL(uncached_free_page);
/*
* uncached_build_memmap,
*
* @uc_start: uncached starting address of a chunk of uncached memory
* @uc_end: uncached ending address of a chunk of uncached memory
* @arg: ignored, (NULL argument passed in on call to efi_memmap_walk_uc())
*
* Called at boot time to build a map of pages that can be used for
* memory special operations.
*/
static int __init
uncached_build_memmap(unsigned long start, unsigned long end, void *arg)
static int __init uncached_build_memmap(unsigned long uc_start,
unsigned long uc_end, void *arg)
{
long length = end - start;
int node;
dprintk(KERN_ERR "uncached_build_memmap(%lx %lx)\n", start, end);
int nid = paddr_to_nid(uc_start - __IA64_UNCACHED_OFFSET);
struct gen_pool *pool = uncached_pool[nid];
size_t size = uc_end - uc_start;
touch_softlockup_watchdog();
memset((char *)start, 0, length);
node = paddr_to_nid(start - __IA64_UNCACHED_OFFSET);
for (; start < end ; start += PAGE_SIZE) {
dprintk(KERN_INFO "sticking %lx into the pool!\n", start);
gen_pool_free(uncached_pool[node], start, PAGE_SIZE);
if (pool != NULL) {
memset((char *)uc_start, 0, size);
(void) gen_pool_add(pool, uc_start, size, nid);
}
return 0;
}
static int __init uncached_init(void) {
int i;
static int __init uncached_init(void)
{
int nid;
for (i = 0; i < MAX_NUMNODES; i++) {
if (!node_online(i))
continue;
uncached_pool[i] = gen_pool_create(0, IA64_GRANULE_SHIFT,
&uncached_get_new_chunk, i);
for_each_online_node(nid) {
uncached_pool[nid] = gen_pool_create(PAGE_SHIFT, nid);
}
efi_memmap_walk_uc(uncached_build_memmap);
efi_memmap_walk_uc(uncached_build_memmap, NULL);
return 0;
}

15
arch/ia64/sn/kernel/sn2/cache.c
View File

@ -3,11 +3,12 @@
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2001-2003 Silicon Graphics, Inc. All rights reserved.
* Copyright (C) 2001-2003, 2006 Silicon Graphics, Inc. All rights reserved.
*
*/
#include <linux/module.h>
#include <asm/pgalloc.h>
#include <asm/sn/arch.h>
/**
* sn_flush_all_caches - flush a range of address from all caches (incl. L4)
@ -17,18 +18,24 @@
* Flush a range of addresses from all caches including L4.
* All addresses fully or partially contained within
* @flush_addr to @flush_addr + @bytes are flushed
* from the all caches.
* from all caches.
*/
void
sn_flush_all_caches(long flush_addr, long bytes)
{
flush_icache_range(flush_addr, flush_addr+bytes);
unsigned long addr = flush_addr;
/* SHub1 requires a cached address */
if (is_shub1() && (addr & RGN_BITS) == RGN_BASE(RGN_UNCACHED))
addr = (addr - RGN_BASE(RGN_UNCACHED)) + RGN_BASE(RGN_KERNEL);
flush_icache_range(addr, addr + bytes);
/*
* The last call may have returned before the caches
* were actually flushed, so we call it again to make
* sure.
*/
flush_icache_range(flush_addr, flush_addr+bytes);
flush_icache_range(addr, addr + bytes);
mb();
}
EXPORT_SYMBOL(sn_flush_all_caches);

43
include/linux/genalloc.h
View File

@ -4,37 +4,32 @@
* Uses for this includes on-device special memory, uncached memory
* etc.
*
* This code is based on the buddy allocator found in the sym53c8xx_2
* driver, adapted for general purpose use.
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
#include <linux/spinlock.h>
#define ALLOC_MIN_SHIFT 5 /* 32 bytes minimum */
/*
* Link between free memory chunks of a given size.
*/
struct gen_pool_link {
struct gen_pool_link *next;
};
/*
* Memory pool descriptor.
* General purpose special memory pool descriptor.
*/
struct gen_pool {
spinlock_t lock;
unsigned long (*get_new_chunk)(struct gen_pool *);
struct gen_pool *next;
struct gen_pool_link *h;
unsigned long private;
int max_chunk_shift;
rwlock_t lock;
struct list_head chunks; /* list of chunks in this pool */
int min_alloc_order; /* minimum allocation order */
};
unsigned long gen_pool_alloc(struct gen_pool *poolp, int size);
void gen_pool_free(struct gen_pool *mp, unsigned long ptr, int size);
struct gen_pool *gen_pool_create(int nr_chunks, int max_chunk_shift,
unsigned long (*fp)(struct gen_pool *),
unsigned long data);
/*
* General purpose special memory pool chunk descriptor.
*/
struct gen_pool_chunk {
spinlock_t lock;
struct list_head next_chunk; /* next chunk in pool */
unsigned long start_addr; /* starting address of memory chunk */
unsigned long end_addr; /* ending address of memory chunk */
unsigned long bits[0]; /* bitmap for allocating memory chunk */
};
extern struct gen_pool *gen_pool_create(int, int);
extern int gen_pool_add(struct gen_pool *, unsigned long, size_t, int);
extern unsigned long gen_pool_alloc(struct gen_pool *, size_t);
extern void gen_pool_free(struct gen_pool *, unsigned long, size_t);

255
lib/genalloc.c
View File

@ -4,10 +4,6 @@
* Uses for this includes on-device special memory, uncached memory
* etc.
*
* This code is based on the buddy allocator found in the sym53c8xx_2
* driver Copyright (C) 1999-2001 Gerard Roudier <groudier@free.fr>,
* and adapted for general purpose use.
*
* Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org>
*
* This source code is licensed under the GNU General Public License,
@ -15,172 +11,155 @@
*/
#include <linux/module.h>
#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/spinlock.h>
#include <linux/genalloc.h>
#include <asm/page.h>
struct gen_pool *gen_pool_create(int nr_chunks, int max_chunk_shift,
unsigned long (*fp)(struct gen_pool *),
unsigned long data)
/*
* Create a new special memory pool.
*
* @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
* @nid: node id of the node the pool structure should be allocated on, or -1
*/
struct gen_pool *gen_pool_create(int min_alloc_order, int nid)
{
struct gen_pool *poolp;
unsigned long tmp;
int i;
struct gen_pool *pool;
/*
* This is really an arbitrary limit, +10 is enough for
* IA64_GRANULE_SHIFT, aka 16MB. If anyone needs a large limit
* this can be increased without problems.
*/
if ((max_chunk_shift > (PAGE_SHIFT + 10)) ||
((max_chunk_shift < ALLOC_MIN_SHIFT) && max_chunk_shift))
return NULL;
if (!max_chunk_shift)
max_chunk_shift = PAGE_SHIFT;
poolp = kmalloc(sizeof(struct gen_pool), GFP_KERNEL);
if (!poolp)
return NULL;
memset(poolp, 0, sizeof(struct gen_pool));
poolp->h = kmalloc(sizeof(struct gen_pool_link) *
(max_chunk_shift - ALLOC_MIN_SHIFT + 1),
GFP_KERNEL);
if (!poolp->h) {
printk(KERN_WARNING "gen_pool_alloc() failed to allocate\n");
kfree(poolp);
return NULL;
pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid);
if (pool != NULL) {
rwlock_init(&pool->lock);
INIT_LIST_HEAD(&pool->chunks);
pool->min_alloc_order = min_alloc_order;
}
memset(poolp->h, 0, sizeof(struct gen_pool_link) *
(max_chunk_shift - ALLOC_MIN_SHIFT + 1));
spin_lock_init(&poolp->lock);
poolp->get_new_chunk = fp;
poolp->max_chunk_shift = max_chunk_shift;
poolp->private = data;
for (i = 0; i < nr_chunks; i++) {
tmp = poolp->get_new_chunk(poolp);
printk(KERN_INFO "allocated %lx\n", tmp);
if (!tmp)
break;
gen_pool_free(poolp, tmp, (1 << poolp->max_chunk_shift));
}
return poolp;
return pool;
}
EXPORT_SYMBOL(gen_pool_create);
/*
* Simple power of two buddy-like generic allocator.
* Provides naturally aligned memory chunks.
* Add a new chunk of memory to the specified pool.
*
* @pool: pool to add new memory chunk to
* @addr: starting address of memory chunk to add to pool
* @size: size in bytes of the memory chunk to add to pool
* @nid: node id of the node the chunk structure and bitmap should be
* allocated on, or -1
*/
unsigned long gen_pool_alloc(struct gen_pool *poolp, int size)
int gen_pool_add(struct gen_pool *pool, unsigned long addr, size_t size,
int nid)
{
int j, i, s, max_chunk_size;
unsigned long a, flags;
struct gen_pool_link *h = poolp->h;
struct gen_pool_chunk *chunk;
int nbits = size >> pool->min_alloc_order;
int nbytes = sizeof(struct gen_pool_chunk) +
(nbits + BITS_PER_BYTE - 1) / BITS_PER_BYTE;
max_chunk_size = 1 << poolp->max_chunk_shift;
chunk = kmalloc_node(nbytes, GFP_KERNEL, nid);
if (unlikely(chunk == NULL))
return -1;
if (size > max_chunk_size)
memset(chunk, 0, nbytes);
spin_lock_init(&chunk->lock);
chunk->start_addr = addr;
chunk->end_addr = addr + size;
write_lock(&pool->lock);
list_add(&chunk->next_chunk, &pool->chunks);
write_unlock(&pool->lock);
return 0;
}
EXPORT_SYMBOL(gen_pool_add);
/*
* Allocate the requested number of bytes from the specified pool.
* Uses a first-fit algorithm.
*
* @pool: pool to allocate from
* @size: number of bytes to allocate from the pool
*/
unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
{
struct list_head *_chunk;
struct gen_pool_chunk *chunk;
unsigned long addr, flags;
int order = pool->min_alloc_order;
int nbits, bit, start_bit, end_bit;
if (size == 0)
return 0;
size = max(size, 1 << ALLOC_MIN_SHIFT);
i = fls(size - 1);
s = 1 << i;
j = i -= ALLOC_MIN_SHIFT;
nbits = (size + (1UL << order) - 1) >> order;
spin_lock_irqsave(&poolp->lock, flags);
while (!h[j].next) {
if (s == max_chunk_size) {
struct gen_pool_link *ptr;
spin_unlock_irqrestore(&poolp->lock, flags);
ptr = (struct gen_pool_link *)poolp->get_new_chunk(poolp);
spin_lock_irqsave(&poolp->lock, flags);
h[j].next = ptr;
if (h[j].next)
h[j].next->next = NULL;
break;
read_lock(&pool->lock);
list_for_each(_chunk, &pool->chunks) {
chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
end_bit = (chunk->end_addr - chunk->start_addr) >> order;
end_bit -= nbits + 1;
spin_lock_irqsave(&chunk->lock, flags);
bit = -1;
while (bit + 1 < end_bit) {
bit = find_next_zero_bit(chunk->bits, end_bit, bit + 1);
if (bit >= end_bit)
break;
start_bit = bit;
if (nbits > 1) {
bit = find_next_bit(chunk->bits, bit + nbits,
bit + 1);
if (bit - start_bit < nbits)
continue;
}
addr = chunk->start_addr +
((unsigned long)start_bit << order);
while (nbits--)
__set_bit(start_bit++, &chunk->bits);
spin_unlock_irqrestore(&chunk->lock, flags);
read_unlock(&pool->lock);
return addr;
}
j++;
s <<= 1;
spin_unlock_irqrestore(&chunk->lock, flags);
}
a = (unsigned long) h[j].next;
if (a) {
h[j].next = h[j].next->next;
/*
* This should be split into a seperate function doing
* the chunk split in order to support custom
* handling memory not physically accessible by host
*/
while (j > i) {
j -= 1;
s >>= 1;
h[j].next = (struct gen_pool_link *) (a + s);
h[j].next->next = NULL;
}
}
spin_unlock_irqrestore(&poolp->lock, flags);
return a;
read_unlock(&pool->lock);
return 0;
}
EXPORT_SYMBOL(gen_pool_alloc);
/*
* Counter-part of the generic allocator.
* Free the specified memory back to the specified pool.
*
* @pool: pool to free to
* @addr: starting address of memory to free back to pool
* @size: size in bytes of memory to free
*/
void gen_pool_free(struct gen_pool *poolp, unsigned long ptr, int size)
void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size)
{
struct gen_pool_link *q;
struct gen_pool_link *h = poolp->h;
unsigned long a, b, flags;
int i, s, max_chunk_size;
struct list_head *_chunk;
struct gen_pool_chunk *chunk;
unsigned long flags;
int order = pool->min_alloc_order;
int bit, nbits;
max_chunk_size = 1 << poolp->max_chunk_shift;
nbits = (size + (1UL << order) - 1) >> order;
if (size > max_chunk_size)
return;
read_lock(&pool->lock);
list_for_each(_chunk, &pool->chunks) {
chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
size = max(size, 1 << ALLOC_MIN_SHIFT);
i = fls(size - 1);
s = 1 << i;
i -= ALLOC_MIN_SHIFT;
a = ptr;
spin_lock_irqsave(&poolp->lock, flags);
while (1) {
if (s == max_chunk_size) {
((struct gen_pool_link *)a)->next = h[i].next;
h[i].next = (struct gen_pool_link *)a;
if (addr >= chunk->start_addr && addr < chunk->end_addr) {
BUG_ON(addr + size > chunk->end_addr);
spin_lock_irqsave(&chunk->lock, flags);
bit = (addr - chunk->start_addr) >> order;
while (nbits--)
__clear_bit(bit++, &chunk->bits);
spin_unlock_irqrestore(&chunk->lock, flags);
break;
}
b = a ^ s;
q = &h[i];
while (q->next && q->next != (struct gen_pool_link *)b)
q = q->next;
if (!q->next) {
((struct gen_pool_link *)a)->next = h[i].next;
h[i].next = (struct gen_pool_link *)a;
break;
}
q->next = q->next->next;
a = a & b;
s <<= 1;
i++;
}
spin_unlock_irqrestore(&poolp->lock, flags);
BUG_ON(nbits > 0);
read_unlock(&pool->lock);
}
EXPORT_SYMBOL(gen_pool_free);