Rusty Russell
2005-Feb-02 06:21 UTC
[Xen-devel] [PATCH 3/3] Replace slab.c with a very simple allocator.
slab.c in Linux is not a very nice piece of code: the version in Xen has
been hacked a certain amount and is not a vision of beauty either.
Given how rare and non-time-critical dynamic allocations are in Xen,
this replaces the 1800-line slab.c with a 160-line malloc.c which is
written as simply as possible for future enhancement.
Tested in userspace, boots Xen fine.
Rusty.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (authored)
diff -urpN --exclude TAGS -X
/home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal
xen-unstable-pre/xen/arch/x86/setup.c xen-unstable-working/xen/arch/x86/setup.c
--- xen-unstable-pre/xen/arch/x86/setup.c 2005-02-02 16:02:39.000000000 +1100
+++ xen-unstable-working/xen/arch/x86/setup.c 2005-02-01 16:57:17.000000000
+1100
@@ -598,10 +598,6 @@ void __init __start_xen(multiboot_info_t
early_boot = 0;
- /* Initialise the slab allocator. */
- xmem_cache_init();
- xmem_cache_sizes_init(max_page);
-
start_of_day();
grant_table_init();
diff -urpN --exclude TAGS -X
/home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal
xen-unstable-pre/xen/common/malloc.c xen-unstable-working/xen/common/malloc.c
--- xen-unstable-pre/xen/common/malloc.c 1970-01-01 10:00:00.000000000 +1000
+++ xen-unstable-working/xen/common/malloc.c 2005-02-02 16:18:19.000000000 +1100
@@ -0,0 +1,164 @@
+/* Simple allocator for Xen. If larger than a page, simply use the
+ * page-order allocator.
+ *
+ * Copyright (C) 2005 Rusty Russell IBM Corporation
+ *
+ * This program 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+#include <xen/mm.h>
+#include <xen/spinlock.h>
+#include <xen/ac_timer.h>
+
+#define BUG_ON(x) do { if (x) BUG(); }while(0)
+
+static LIST_HEAD(freelist);
+static spinlock_t freelist_lock = SPIN_LOCK_UNLOCKED;
+
+struct xmalloc_hdr
+{
+ /* Total including this hdr: negative means allocated. */
+ long size;
+ union {
+ struct list_head freelist;
+ char data[0];
+ } u;
+};
+
+static void maybe_split(struct xmalloc_hdr *hdr, size_t size, size_t block)
+{
+ size_t leftover = block - size;
+
+ /* If enough left to make a block, put it on free list. */
+ if (leftover >= sizeof(struct xmalloc_hdr)) {
+ struct xmalloc_hdr *extra;
+
+ extra = (void *)hdr + size;
+ extra->size = leftover;
+ list_add(&extra->u.freelist, &freelist);
+ } else
+ size = block;
+
+ hdr->size = -size;
+}
+
+static void *xmalloc_new_page(size_t size)
+{
+ struct xmalloc_hdr *hdr;
+ unsigned long flags;
+
+ hdr = (void *)alloc_xenheap_pages(0);
+ if (!hdr)
+ return NULL;
+
+ spin_lock_irqsave(&freelist_lock, flags);
+ maybe_split(hdr, size, PAGE_SIZE);
+ spin_unlock_irqrestore(&freelist_lock, flags);
+ return hdr->u.data;
+}
+
+/* Big object? Just use page allocator. */
+static void *xmalloc_whole_pages(size_t size)
+{
+ struct xmalloc_hdr *hdr;
+ unsigned int pageorder = get_order(size);
+
+ hdr = (void *)alloc_xenheap_pages(pageorder);
+ if (!hdr)
+ return NULL;
+
+ hdr->size = -(1 << (pageorder + PAGE_SHIFT));
+ return hdr->u.data;
+}
+
+void *__xmalloc(size_t size, const char *file, unsigned int line)
+{
+ struct xmalloc_hdr *i;
+ unsigned long flags;
+
+ /* Add room for header, align to unsigned long. */
+ size += offsetof(struct xmalloc_hdr, u.data);
+ size = ((size + sizeof(unsigned long)-1)&~(sizeof(unsigned long)-1));
+
+ /* Minimum size is size of freelist entry. */
+ if (size < sizeof(*i))
+ size = sizeof(*i);
+
+ /* For big allocs, give them whole pages. */
+ if (size >= PAGE_SIZE)
+ return xmalloc_whole_pages(size);
+
+ /* Search free list */
+ spin_lock_irqsave(&freelist_lock, flags);
+ list_for_each_entry(i, &freelist, u.freelist) {
+ if (i->size >= size) {
+ list_del(&i->u.freelist);
+ maybe_split(i, size, i->size);
+ spin_unlock_irqrestore(&freelist_lock, flags);
+ return i->u.data;
+ }
+ }
+ spin_unlock_irqrestore(&freelist_lock, flags);
+
+ /* Alloc a new page and return from that. */
+ return xmalloc_new_page(size);
+}
+
+void __xfree(const void *p, const char *file, unsigned int line)
+{
+ unsigned long flags;
+ struct xmalloc_hdr *i, *tmp, *hdr;
+
+ if (!p)
+ return;
+
+ hdr = container_of((void *)p, struct xmalloc_hdr, u.data);
+
+ /* We know hdr will be on same page. */
+ BUG_ON(((long)p & PAGE_MASK) != ((long)hdr & PAGE_MASK));
+
+ /* Not previously freed. */
+ BUG_ON(hdr->size > 0);
+ hdr->size = -hdr->size;
+
+ /* Big allocs free directly. */
+ if (hdr->size >= PAGE_SIZE) {
+ free_xenheap_pages((unsigned long)hdr, get_order(hdr->size));
+ return;
+ }
+
+ /* Merge with other free block, or put in list. */
+ spin_lock_irqsave(&freelist_lock, flags);
+ list_for_each_entry_safe(i, tmp, &freelist, u.freelist) {
+ /* We follow this block? Swallow it. */
+ if ((void *)i + i->size == (void *)hdr) {
+ list_del(&i->u.freelist);
+ i->size += hdr->size;
+ hdr = i;
+ }
+ /* It follows us? Delete it and add it to us. */
+ if ((void *)hdr + hdr->size == (void *)i) {
+ list_del(&i->u.freelist);
+ hdr->size += i->size;
+ }
+ }
+
+ /* Did we free entire page? */
+ if (hdr->size == PAGE_SIZE) {
+ BUG_ON((((unsigned long)hdr) & (PAGE_SIZE-1)) != 0);
+ free_xenheap_pages((unsigned long)hdr, 0);
+ } else
+ list_add(&hdr->u.freelist, &freelist);
+ spin_unlock_irqrestore(&freelist_lock, flags);
+}
diff -urpN --exclude TAGS -X
/home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal
xen-unstable-pre/xen/common/page_alloc.c
xen-unstable-working/xen/common/page_alloc.c
--- xen-unstable-pre/xen/common/page_alloc.c 2005-01-30 15:28:45.000000000 +1100
+++ xen-unstable-working/xen/common/page_alloc.c 2005-02-01 16:57:17.000000000
+1100
@@ -403,9 +403,8 @@ unsigned long alloc_xenheap_pages(unsign
{
unsigned long flags;
struct pfn_info *pg;
- int i, attempts = 0;
+ int i;
- retry:
local_irq_save(flags);
pg = alloc_heap_pages(MEMZONE_XEN, order);
local_irq_restore(flags);
@@ -425,14 +424,7 @@ unsigned long alloc_xenheap_pages(unsign
return (unsigned long)page_to_virt(pg);
no_memory:
- if ( attempts++ < 8 )
- {
- xmem_cache_reap();
- goto retry;
- }
-
printk("Cannot handle page request order %d!\n", order);
- dump_slabinfo();
return 0;
}
diff -urpN --exclude TAGS -X
/home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal
xen-unstable-pre/xen/common/slab.c xen-unstable-working/xen/common/slab.c
--- xen-unstable-pre/xen/common/slab.c 2005-01-30 15:28:43.000000000 +1100
+++ xen-unstable-working/xen/common/slab.c 1970-01-01 10:00:00.000000000 +1000
@@ -1,1844 +0,0 @@
-/*
- * linux/mm/slab.c
- * Written by Mark Hemment, 1996/97.
- * (markhe@nextd.demon.co.uk)
- *
- * xmem_cache_destroy() + some cleanup - 1999 Andrea Arcangeli
- *
- * Major cleanup, different bufctl logic, per-cpu arrays
- * (c) 2000 Manfred Spraul
- *
- * An implementation of the Slab Allocator as described in outline in;
- * UNIX Internals: The New Frontiers by Uresh Vahalia
- * Pub: Prentice Hall ISBN 0-13-101908-2
- * or with a little more detail in;
- * The Slab Allocator: An Object-Caching Kernel Memory Allocator
- * Jeff Bonwick (Sun Microsystems).
- * Presented at: USENIX Summer 1994 Technical Conference
- *
- *
- * The memory is organized in caches, one cache for each object type.
- * (e.g. inode_cache, dentry_cache, buffer_head, vm_area_struct)
- * Each cache consists out of many slabs (they are small (usually one
- * page long) and always contiguous), and each slab contains multiple
- * initialized objects.
- *
- * In order to reduce fragmentation, the slabs are sorted in 3 groups:
- * full slabs with 0 free objects
- * partial slabs
- * empty slabs with no allocated objects
- *
- * If partial slabs exist, then new allocations come from these slabs,
- * otherwise from empty slabs or new slabs are allocated.
- *
- * xmem_cache_destroy() CAN CRASH if you try to allocate from the cache
- * during xmem_cache_destroy(). The caller must prevent concurrent allocs.
- *
- * On SMP systems, each cache has a short per-cpu head array, most allocs
- * and frees go into that array, and if that array overflows, then 1/2
- * of the entries in the array are given back into the global cache.
- * This reduces the number of spinlock operations.
- *
- * The c_cpuarray may not be read with enabled local interrupts.
- *
- * SMP synchronization:
- * constructors and destructors are called without any locking.
- * Several members in xmem_cache_t and slab_t never change, they
- * are accessed without any locking.
- * The per-cpu arrays are never accessed from the wrong cpu, no locking.
- * The non-constant members are protected with a per-cache irq spinlock.
- */
-
-#include <xen/config.h>
-#include <xen/init.h>
-#include <xen/types.h>
-#include <xen/lib.h>
-#include <xen/slab.h>
-#include <xen/list.h>
-#include <xen/spinlock.h>
-#include <xen/errno.h>
-#include <xen/smp.h>
-#include <xen/sched.h>
-
-/*
- * DEBUG - 1 for xmem_cache_create() to honour; SLAB_DEBUG_INITIAL,
- * SLAB_RED_ZONE & SLAB_POISON.
- * 0 for faster, smaller code (especially in the critical paths).
- *
- * STATS - 1 to collect stats for /proc/slabinfo.
- * 0 for faster, smaller code (especially in the critical paths).
- *
- * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
- */
-#ifdef CONFIG_DEBUG_SLAB
-#define DEBUG 1
-#define STATS 1
-#define FORCED_DEBUG 1
-#else
-#define DEBUG 0
-#define STATS 0
-#define FORCED_DEBUG 0
-#endif
-
-/*
- * Parameters for xmem_cache_reap
- */
-#define REAP_SCANLEN 10
-#define REAP_PERFECT 10
-
-/* Shouldn''t this be in a header file somewhere? */
-#define BYTES_PER_WORD sizeof(void *)
-
-/* Legal flag mask for xmem_cache_create(). */
-#if DEBUG
-#define CREATE_MASK (SLAB_DEBUG_INITIAL | SLAB_RED_ZONE | \
- SLAB_POISON | SLAB_HWCACHE_ALIGN | \
- SLAB_NO_REAP)
-#else
-#define CREATE_MASK (SLAB_HWCACHE_ALIGN | SLAB_NO_REAP)
-#endif
-
-/*
- * xmem_bufctl_t:
- *
- * Bufctl''s are used for linking objs within a slab
- * linked offsets.
- *
- * This implementaion relies on "struct page" for locating the cache
&
- * slab an object belongs to.
- * This allows the bufctl structure to be small (one int), but limits
- * the number of objects a slab (not a cache) can contain when off-slab
- * bufctls are used. The limit is the size of the largest general cache
- * that does not use off-slab slabs.
- * For 32bit archs with 4 kB pages, is this 56.
- * This is not serious, as it is only for large objects, when it is unwise
- * to have too many per slab.
- * Note: This limit can be raised by introducing a general cache whose size
- * is less than 512 (PAGE_SIZE<<3), but greater than 256.
- */
-
-#define BUFCTL_END (((xmem_bufctl_t)(~0U))-0)
-#define BUFCTL_FREE (((xmem_bufctl_t)(~0U))-1)
-#define SLAB_LIMIT (((xmem_bufctl_t)(~0U))-2)
-
-/* Max number of objs-per-slab for caches which use off-slab slabs.
- * Needed to avoid a possible looping condition in xmem_cache_grow().
- */
-static unsigned long offslab_limit;
-
-/*
- * slab_t
- *
- * Manages the objs in a slab. Placed either at the beginning of mem allocated
- * for a slab, or allocated from an general cache.
- * Slabs are chained into three list: fully used, partial, fully free slabs.
- */
-typedef struct slab_s {
- struct list_head list;
- unsigned long colouroff;
- void *s_mem; /* including colour offset */
- unsigned int inuse; /* num of objs active in slab */
- xmem_bufctl_t free;
-} slab_t;
-
-#define slab_bufctl(slabp) \
- ((xmem_bufctl_t *)(((slab_t*)slabp)+1))
-
-/*
- * cpucache_t
- *
- * Per cpu structures
- * The limit is stored in the per-cpu structure to reduce the data cache
- * footprint.
- */
-typedef struct cpucache_s {
- unsigned int avail;
- unsigned int limit;
-} cpucache_t;
-
-#define cc_entry(cpucache) \
- ((void **)(((cpucache_t*)(cpucache))+1))
-#define cc_data(cachep) \
- ((cachep)->cpudata[smp_processor_id()])
-/*
- * xmem_cache_t
- *
- * manages a cache.
- */
-
-#define CACHE_NAMELEN 20 /* max name length for a slab cache */
-
-struct xmem_cache_s {
-/* 1) each alloc & free */
- /* full, partial first, then free */
- struct list_head slabs_full;
- struct list_head slabs_partial;
- struct list_head slabs_free;
- unsigned int objsize;
- unsigned int flags; /* constant flags */
- unsigned int num; /* # of objs per slab */
- spinlock_t spinlock;
-#ifdef CONFIG_SMP
- unsigned int batchcount;
-#endif
-
-/* 2) slab additions /removals */
- /* order of pgs per slab (2^n) */
- unsigned int gfporder;
- size_t colour; /* cache colouring range */
- unsigned int colour_off; /* colour offset */
- unsigned int colour_next; /* cache colouring */
- xmem_cache_t *slabp_cache;
- unsigned int growing;
- unsigned int dflags; /* dynamic flags */
-
- /* constructor func */
- void (*ctor)(void *, xmem_cache_t *, unsigned long);
-
- /* de-constructor func */
- void (*dtor)(void *, xmem_cache_t *, unsigned long);
-
- unsigned long failures;
-
-/* 3) cache creation/removal */
- char name[CACHE_NAMELEN];
- struct list_head next;
-#ifdef CONFIG_SMP
-/* 4) per-cpu data */
- cpucache_t *cpudata[NR_CPUS];
-#endif
-#if STATS
- unsigned long num_active;
- unsigned long num_allocations;
- unsigned long high_mark;
- unsigned long grown;
- unsigned long reaped;
- unsigned long errors;
-#ifdef CONFIG_SMP
- atomic_t allochit;
- atomic_t allocmiss;
- atomic_t freehit;
- atomic_t freemiss;
-#endif
-#endif
-};
-
-/* internal c_flags */
-#define CFLGS_OFF_SLAB 0x010000UL /* slab management in own cache */
-#define CFLGS_OPTIMIZE 0x020000UL /* optimized slab lookup */
-
-/* c_dflags (dynamic flags). Need to hold the spinlock to access this member */
-#define DFLGS_GROWN 0x000001UL /* don''t reap a recently grown */
-
-#define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
-#define OPTIMIZE(x) ((x)->flags & CFLGS_OPTIMIZE)
-#define GROWN(x) ((x)->dlags & DFLGS_GROWN)
-
-#if STATS
-#define STATS_INC_ACTIVE(x) ((x)->num_active++)
-#define STATS_DEC_ACTIVE(x) ((x)->num_active--)
-#define STATS_INC_ALLOCED(x) ((x)->num_allocations++)
-#define STATS_INC_GROWN(x) ((x)->grown++)
-#define STATS_INC_REAPED(x) ((x)->reaped++)
-#define STATS_SET_HIGH(x) do { if ((x)->num_active > (x)->high_mark) \
- (x)->high_mark = (x)->num_active; \
- } while (0)
-#define STATS_INC_ERR(x) ((x)->errors++)
-#else
-#define STATS_INC_ACTIVE(x) do { } while (0)
-#define STATS_DEC_ACTIVE(x) do { } while (0)
-#define STATS_INC_ALLOCED(x) do { } while (0)
-#define STATS_INC_GROWN(x) do { } while (0)
-#define STATS_INC_REAPED(x) do { } while (0)
-#define STATS_SET_HIGH(x) do { } while (0)
-#define STATS_INC_ERR(x) do { } while (0)
-#endif
-
-#if STATS && defined(CONFIG_SMP)
-#define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit)
-#define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss)
-#define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit)
-#define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss)
-#else
-#define STATS_INC_ALLOCHIT(x) do { } while (0)
-#define STATS_INC_ALLOCMISS(x) do { } while (0)
-#define STATS_INC_FREEHIT(x) do { } while (0)
-#define STATS_INC_FREEMISS(x) do { } while (0)
-#endif
-
-#if DEBUG
-/* Magic nums for obj red zoning.
- * Placed in the first word before and the first word after an obj.
- */
-#define RED_MAGIC1 0x5A2CF071UL /* when obj is active */
-#define RED_MAGIC2 0x170FC2A5UL /* when obj is inactive */
-
-/* ...and for poisoning */
-#define POISON_BYTE 0x5a /* byte value for poisoning */
-#define POISON_END 0xa5 /* end-byte of poisoning */
-
-#endif
-
-/* maximum size of an obj (in 2^order pages) */
-#define MAX_OBJ_ORDER 5 /* 32 pages */
-
-/*
- * Do not go above this order unless 0 objects fit into the slab.
- */
-#define BREAK_GFP_ORDER_HI 2
-#define BREAK_GFP_ORDER_LO 1
-static int slab_break_gfp_order = BREAK_GFP_ORDER_LO;
-
-/*
- * Absolute limit for the gfp order
- */
-#define MAX_GFP_ORDER 5 /* 32 pages */
-
-
-/* Macros for storing/retrieving the cachep and or slab from the
- * global ''mem_map''. These are used to find the slab an obj
belongs to.
- * With xfree(), these are used to find the cache which an obj belongs to.
- */
-#define SET_PAGE_CACHE(pg,x) ((pg)->list.next = (struct list_head *)(x))
-#define GET_PAGE_CACHE(pg) ((xmem_cache_t *)(pg)->list.next)
-#define SET_PAGE_SLAB(pg,x) ((pg)->list.prev = (struct list_head *)(x))
-#define GET_PAGE_SLAB(pg) ((slab_t *)(pg)->list.prev)
-
-/* Size description struct for general caches. */
-typedef struct cache_sizes {
- size_t cs_size;
- xmem_cache_t *cs_cachep;
-} cache_sizes_t;
-
-static cache_sizes_t cache_sizes[] = {
- { 32, NULL},
- { 64, NULL},
- { 128, NULL},
- { 256, NULL},
- { 512, NULL},
- { 1024, NULL},
- { 2048, NULL},
- { 4096, NULL},
- { 8192, NULL},
- { 16384, NULL},
- { 32768, NULL},
- { 65536, NULL},
- { 0, NULL}
-};
-
-/* internal cache of cache description objs */
-static xmem_cache_t cache_cache = {
- slabs_full: LIST_HEAD_INIT(cache_cache.slabs_full),
- slabs_partial: LIST_HEAD_INIT(cache_cache.slabs_partial),
- slabs_free: LIST_HEAD_INIT(cache_cache.slabs_free),
- objsize: sizeof(xmem_cache_t),
- flags: SLAB_NO_REAP,
- spinlock: SPIN_LOCK_UNLOCKED,
- colour_off: L1_CACHE_BYTES,
- name: "xmem_cache"
-};
-
-/* Guard access to the cache-chain. */
-/* KAF: No semaphores, as we''ll never wait around for I/O. */
-static spinlock_t cache_chain_sem;
-#define init_MUTEX(_m) spin_lock_init(_m)
-#define down(_m) spin_lock_irqsave(_m,spin_flags)
-#define up(_m) spin_unlock_irqrestore(_m,spin_flags)
-
-/* Place maintainer for reaping. */
-static xmem_cache_t *clock_searchp = &cache_cache;
-
-#define cache_chain (cache_cache.next)
-
-#ifdef CONFIG_SMP
-/*
- * chicken and egg problem: delay the per-cpu array allocation
- * until the general caches are up.
- */
-static int g_cpucache_up;
-
-static void enable_cpucache (xmem_cache_t *cachep);
-static void enable_all_cpucaches (void);
-#endif
-
-/* Cal the num objs, wastage, and bytes left over for a given slab size. */
-static void xmem_cache_estimate (unsigned long gfporder, size_t size,
- int flags, size_t *left_over, unsigned int
*num)
-{
- int i;
- size_t wastage = PAGE_SIZE<<gfporder;
- size_t extra = 0;
- size_t base = 0;
-
- if (!(flags & CFLGS_OFF_SLAB)) {
- base = sizeof(slab_t);
- extra = sizeof(xmem_bufctl_t);
- }
- i = 0;
- while (i*size + L1_CACHE_ALIGN(base+i*extra) <= wastage)
- i++;
- if (i > 0)
- i--;
-
- if (i > SLAB_LIMIT)
- i = SLAB_LIMIT;
-
- *num = i;
- wastage -= i*size;
- wastage -= L1_CACHE_ALIGN(base+i*extra);
- *left_over = wastage;
-}
-
-/* Initialisation - setup the `cache'' cache. */
-void __init xmem_cache_init(void)
-{
- size_t left_over;
-
- init_MUTEX(&cache_chain_sem);
- INIT_LIST_HEAD(&cache_chain);
-
- xmem_cache_estimate(0, cache_cache.objsize, 0,
- &left_over, &cache_cache.num);
- if (!cache_cache.num)
- BUG();
-
- cache_cache.colour = left_over/cache_cache.colour_off;
- cache_cache.colour_next = 0;
-}
-
-
-/* Initialisation - setup remaining internal and general caches.
- * Called after the gfp() functions have been enabled, and before smp_init().
- */
-void __init xmem_cache_sizes_init(unsigned long num_physpages)
-{
- cache_sizes_t *sizes = cache_sizes;
- char name[20];
- /*
- * Fragmentation resistance on low memory - only use bigger
- * page orders on machines with more than 32MB of memory.
- */
- if (num_physpages > (32 << 20) >> PAGE_SHIFT)
- slab_break_gfp_order = BREAK_GFP_ORDER_HI;
- do {
- /* For performance, all the general caches are L1 aligned.
- * This should be particularly beneficial on SMP boxes, as it
- * eliminates "false sharing".
- * Note for systems short on memory removing the alignment will
- * allow tighter packing of the smaller caches. */
- sprintf(name,"size-%Zd",sizes->cs_size);
- if (!(sizes->cs_cachep - xmem_cache_create(name,
sizes->cs_size,
- 0, SLAB_HWCACHE_ALIGN, NULL, NULL))) {
- BUG();
- }
-
- /* Inc off-slab bufctl limit until the ceiling is hit. */
- if (!(OFF_SLAB(sizes->cs_cachep))) {
- offslab_limit = sizes->cs_size-sizeof(slab_t);
- offslab_limit /= 2;
- }
- sizes++;
- } while (sizes->cs_size);
-}
-
-int __init xmem_cpucache_init(void)
-{
-#ifdef CONFIG_SMP
- g_cpucache_up = 1;
- enable_all_cpucaches();
-#endif
- return 0;
-}
-
-/*__initcall(xmem_cpucache_init);*/
-
-/* Interface to system''s page allocator. No need to hold the
cache-lock.
- */
-static inline void *xmem_getpages(xmem_cache_t *cachep)
-{
- void *addr;
-
- addr = (void*) alloc_xenheap_pages(cachep->gfporder);
- /* Assume that now we have the pages no one else can legally
- * messes with the ''struct page''s.
- * However vm_scan() might try to test the structure to see if
- * it is a named-page or buffer-page. The members it tests are
- * of no interest here.....
- */
- return addr;
-}
-
-/* Interface to system''s page release. */
-static inline void xmem_freepages (xmem_cache_t *cachep, void *addr)
-{
- unsigned long i = (1<<cachep->gfporder);
- struct pfn_info *page = virt_to_page(addr);
-
- /* free_xenheap_pages() does not clear the type bit - we do that.
- * The pages have been unlinked from their cache-slab,
- * but their ''struct page''s might be accessed in
- * vm_scan(). Shouldn''t be a worry.
- */
- while (i--) {
- PageClearSlab(page);
- page++;
- }
-
- free_xenheap_pages((unsigned long)addr, cachep->gfporder);
-}
-
-#if DEBUG
-static inline void xmem_poison_obj (xmem_cache_t *cachep, void *addr)
-{
- int size = cachep->objsize;
- if (cachep->flags & SLAB_RED_ZONE) {
- addr += BYTES_PER_WORD;
- size -= 2*BYTES_PER_WORD;
- }
- memset(addr, POISON_BYTE, size);
- *(unsigned char *)(addr+size-1) = POISON_END;
-}
-
-static inline int xmem_check_poison_obj (xmem_cache_t *cachep, void *addr)
-{
- int size = cachep->objsize;
- void *end;
- if (cachep->flags & SLAB_RED_ZONE) {
- addr += BYTES_PER_WORD;
- size -= 2*BYTES_PER_WORD;
- }
- end = memchr(addr, POISON_END, size);
- if (end != (addr+size-1))
- return 1;
- return 0;
-}
-#endif
-
-/* Destroy all the objs in a slab, and release the mem back to the system.
- * Before calling the slab must have been unlinked from the cache.
- * The cache-lock is not held/needed.
- */
-static void xmem_slab_destroy (xmem_cache_t *cachep, slab_t *slabp)
-{
- if (cachep->dtor
-#if DEBUG
- || cachep->flags & (SLAB_POISON | SLAB_RED_ZONE)
-#endif
- ) {
- int i;
- for (i = 0; i < cachep->num; i++) {
- void* objp = slabp->s_mem+cachep->objsize*i;
-#if DEBUG
- if (cachep->flags & SLAB_RED_ZONE) {
- if (*((unsigned long*)(objp)) != RED_MAGIC1)
- BUG();
- if (*((unsigned long*)(objp + cachep->objsize
- -BYTES_PER_WORD)) != RED_MAGIC1)
- BUG();
- objp += BYTES_PER_WORD;
- }
-#endif
- if (cachep->dtor)
- (cachep->dtor)(objp, cachep, 0);
-#if DEBUG
- if (cachep->flags & SLAB_RED_ZONE) {
- objp -= BYTES_PER_WORD;
- }
- if ((cachep->flags & SLAB_POISON) &&
- xmem_check_poison_obj(cachep, objp))
- BUG();
-#endif
- }
- }
-
- xmem_freepages(cachep, slabp->s_mem-slabp->colouroff);
- if (OFF_SLAB(cachep))
- xmem_cache_free(cachep->slabp_cache, slabp);
-}
-
-/**
- * xmem_cache_create - Create a cache.
- * @name: A string which is used in /proc/slabinfo to identify this cache.
- * @size: The size of objects to be created in this cache.
- * @offset: The offset to use within the page.
- * @flags: SLAB flags
- * @ctor: A constructor for the objects.
- * @dtor: A destructor for the objects.
- *
- * Returns a ptr to the cache on success, NULL on failure.
- * Cannot be called within a int, but can be interrupted.
- * The @ctor is run when new pages are allocated by the cache
- * and the @dtor is run before the pages are handed back.
- * The flags are
- *
- * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
- * to catch references to uninitialised memory.
- *
- * %SLAB_RED_ZONE - Insert `Red'' zones around the allocated memory to
check
- * for buffer overruns.
- *
- * %SLAB_NO_REAP - Don''t automatically reap this cache when
we''re under
- * memory pressure.
- *
- * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
- * cacheline. This can be beneficial if you''re counting cycles as
closely
- * as davem.
- */
-xmem_cache_t *
-xmem_cache_create (const char *name, size_t size, size_t offset,
- unsigned long flags,
- void (*ctor)(void*, xmem_cache_t *, unsigned long),
- void (*dtor)(void*, xmem_cache_t *, unsigned long))
-{
- const char *func_nm = KERN_ERR "xmem_create: ";
- size_t left_over, align, slab_size;
- xmem_cache_t *cachep = NULL;
- unsigned long spin_flags;
-
- /*
- * Sanity checks... these are all serious usage bugs.
- */
- if ((!name) ||
- ((strlen(name) >= CACHE_NAMELEN - 1)) ||
- (size < BYTES_PER_WORD) ||
- (size > (1<<MAX_OBJ_ORDER)*PAGE_SIZE) ||
- (dtor && !ctor) ||
- (offset < 0 || offset > size))
- BUG();
-
-#if DEBUG
- if ((flags & SLAB_DEBUG_INITIAL) && !ctor) {
- /* No constructor, but inital state check requested */
- printk("%sNo con, but init state check requested - %s\n",
- func_nm, name);
- flags &= ~SLAB_DEBUG_INITIAL;
- }
-
- if ((flags & SLAB_POISON) && ctor) {
- /* request for poisoning, but we can''t do that with a
constructor */
- printk("%sPoisoning requested, but con given - %s\n",
- func_nm, name);
- flags &= ~SLAB_POISON;
- }
-#if FORCED_DEBUG
- if (size < (PAGE_SIZE>>3))
- /*
- * do not red zone large object, causes severe
- * fragmentation.
- */
- flags |= SLAB_RED_ZONE;
- if (!ctor)
- flags |= SLAB_POISON;
-#endif
-#endif
-
- /*
- * Always checks flags, a caller might be expecting debug
- * support which isn''t available.
- */
- if (flags & ~CREATE_MASK)
- BUG();
-
- /* Get cache''s description obj. */
- cachep = (xmem_cache_t *)xmem_cache_alloc(&cache_cache);
- if (!cachep)
- goto opps;
- memset(cachep, 0, sizeof(xmem_cache_t));
-
- /* Check that size is in terms of words. This is needed to avoid
- * unaligned accesses for some archs when redzoning is used, and makes
- * sure any on-slab bufctl''s are also correctly aligned.
- */
- if (size & (BYTES_PER_WORD-1)) {
- size += (BYTES_PER_WORD-1);
- size &= ~(BYTES_PER_WORD-1);
- printk("%sForcing size word alignment - %s\n", func_nm,
name);
- }
-
-#if DEBUG
- if (flags & SLAB_RED_ZONE) {
- /*
- * There is no point trying to honour cache alignment
- * when redzoning.
- */
- flags &= ~SLAB_HWCACHE_ALIGN;
- size += 2*BYTES_PER_WORD; /* words for redzone */
- }
-#endif
- align = BYTES_PER_WORD;
- if (flags & SLAB_HWCACHE_ALIGN)
- align = L1_CACHE_BYTES;
-
- /* Determine if the slab management is ''on'' or
''off'' slab. */
- if (size >= (PAGE_SIZE>>3))
- /*
- * Size is large, assume best to place the slab management obj
- * off-slab (should allow better packing of objs).
- */
- flags |= CFLGS_OFF_SLAB;
-
- if (flags & SLAB_HWCACHE_ALIGN) {
- /* Need to adjust size so that objs are cache aligned. */
- /* Small obj size, can get at least two per cache line. */
- /* FIXME: only power of 2 supported, was better */
- while (size < align/2)
- align /= 2;
- size = (size+align-1)&(~(align-1));
- }
-
- /* Cal size (in pages) of slabs, and the num of objs per slab.
- * This could be made much more intelligent. For now, try to avoid
- * using high page-orders for slabs. When the gfp() funcs are more
- * friendly towards high-order requests, this should be changed.
- */
- do {
- unsigned int break_flag = 0;
- cal_wastage:
- xmem_cache_estimate(cachep->gfporder, size, flags,
- &left_over, &cachep->num);
- if (break_flag)
- break;
- if (cachep->gfporder >= MAX_GFP_ORDER)
- break;
- if (!cachep->num)
- goto next;
- if (flags & CFLGS_OFF_SLAB && cachep->num >
offslab_limit) {
- /* Oops, this num of objs will cause problems. */
- cachep->gfporder--;
- break_flag++;
- goto cal_wastage;
- }
-
- /*
- * Large num of objs is good, but v. large slabs are currently
- * bad for the gfp()s.
- */
- if (cachep->gfporder >= slab_break_gfp_order)
- break;
-
- if ((left_over*8) <= (PAGE_SIZE<<cachep->gfporder))
- break; /* Acceptable internal fragmentation. */
- next:
- cachep->gfporder++;
- } while (1);
-
- if (!cachep->num) {
- printk("xmem_cache_create: couldn''t create cache
%s.\n", name);
- xmem_cache_free(&cache_cache, cachep);
- cachep = NULL;
- goto opps;
- }
- slab_size = L1_CACHE_ALIGN(cachep->num*sizeof(xmem_bufctl_t) +
- sizeof(slab_t));
-
- /*
- * If the slab has been placed off-slab, and we have enough space then
- * move it on-slab. This is at the expense of any extra colouring.
- */
- if (flags & CFLGS_OFF_SLAB && left_over >= slab_size) {
- flags &= ~CFLGS_OFF_SLAB;
- left_over -= slab_size;
- }
-
- /* Offset must be a multiple of the alignment. */
- offset += (align-1);
- offset &= ~(align-1);
- if (!offset)
- offset = L1_CACHE_BYTES;
- cachep->colour_off = offset;
- cachep->colour = left_over/offset;
-
- /* init remaining fields */
- if (!cachep->gfporder && !(flags & CFLGS_OFF_SLAB))
- flags |= CFLGS_OPTIMIZE;
-
- cachep->flags = flags;
- spin_lock_init(&cachep->spinlock);
- cachep->objsize = size;
- INIT_LIST_HEAD(&cachep->slabs_full);
- INIT_LIST_HEAD(&cachep->slabs_partial);
- INIT_LIST_HEAD(&cachep->slabs_free);
-
- if (flags & CFLGS_OFF_SLAB)
- cachep->slabp_cache = xmem_find_general_cachep(slab_size);
- cachep->ctor = ctor;
- cachep->dtor = dtor;
- /* Copy name over so we don''t have problems with unloaded modules
*/
- strcpy(cachep->name, name);
-
-#ifdef CONFIG_SMP
- if (g_cpucache_up)
- enable_cpucache(cachep);
-#endif
- /* Need the semaphore to access the chain. */
- down(&cache_chain_sem);
- {
- xmem_cache_t *pc;
-
- list_for_each_entry(pc, &cache_chain, next) {
- /* The name field is constant - no lock needed. */
- if (!strcmp(pc->name, name))
- BUG();
- }
- }
-
- /* There is no reason to lock our new cache before we
- * link it in - no one knows about it yet...
- */
- list_add(&cachep->next, &cache_chain);
- up(&cache_chain_sem);
- opps:
- return cachep;
-}
-
-
-#if DEBUG
-/*
- * This check if the xmem_cache_t pointer is chained in the cache_cache
- * list. -arca
- */
-static int is_chained_xmem_cache(xmem_cache_t * cachep)
-{
- xmem_cache_t *pc;
- int ret = 0;
- unsigned long spin_flags;
-
- /* Find the cache in the chain of caches. */
- down(&cache_chain_sem);
- list_for_each_entry(pc, &cache_chain, next) {
- if (pc == &cachep) {
- ret = 1;
- break;
- }
- }
- up(&cache_chain_sem);
-
- return ret;
-}
-#else
-#define is_chained_xmem_cache(x) 1
-#endif
-
-#ifdef CONFIG_SMP
-/*
- * Waits for all CPUs to execute func().
- */
-static void smp_call_function_all_cpus(void (*func) (void *arg), void *arg)
-{
- local_irq_disable();
- func(arg);
- local_irq_enable();
-
- if (smp_call_function(func, arg, 1, 1))
- BUG();
-}
-typedef struct ccupdate_struct_s
-{
- xmem_cache_t *cachep;
- cpucache_t *new[NR_CPUS];
-} ccupdate_struct_t;
-
-static void do_ccupdate_local(void *info)
-{
- ccupdate_struct_t *new = (ccupdate_struct_t *)info;
- cpucache_t *old = cc_data(new->cachep);
-
- cc_data(new->cachep) = new->new[smp_processor_id()];
- new->new[smp_processor_id()] = old;
-}
-
-static void free_block (xmem_cache_t* cachep, void** objpp, int len);
-
-static void drain_cpu_caches(xmem_cache_t *cachep)
-{
- ccupdate_struct_t new;
- int i;
- unsigned long spin_flags;
-
- memset(&new.new,0,sizeof(new.new));
-
- new.cachep = cachep;
-
- down(&cache_chain_sem);
- smp_call_function_all_cpus(do_ccupdate_local, (void *)&new);
-
- for (i = 0; i < smp_num_cpus; i++) {
- cpucache_t* ccold = new.new[cpu_logical_map(i)];
- if (!ccold || (ccold->avail == 0))
- continue;
- local_irq_disable();
- free_block(cachep, cc_entry(ccold), ccold->avail);
- local_irq_enable();
- ccold->avail = 0;
- }
- smp_call_function_all_cpus(do_ccupdate_local, (void *)&new);
- up(&cache_chain_sem);
-}
-
-#else
-#define drain_cpu_caches(cachep) do { } while (0)
-#endif
-
-static int __xmem_cache_shrink(xmem_cache_t *cachep)
-{
- slab_t *slabp;
- int ret;
-
- drain_cpu_caches(cachep);
-
- spin_lock_irq(&cachep->spinlock);
-
- /* If the cache is growing, stop shrinking. */
- while (!cachep->growing) {
- struct list_head *p;
-
- p = cachep->slabs_free.prev;
- if (p == &cachep->slabs_free)
- break;
-
- slabp = list_entry(cachep->slabs_free.prev, slab_t, list);
-#if DEBUG
- if (slabp->inuse)
- BUG();
-#endif
- list_del(&slabp->list);
-
- spin_unlock_irq(&cachep->spinlock);
- xmem_slab_destroy(cachep, slabp);
- spin_lock_irq(&cachep->spinlock);
- }
- ret = (!list_empty(&cachep->slabs_full) ||
- !list_empty(&cachep->slabs_partial));
- spin_unlock_irq(&cachep->spinlock);
- return ret;
-}
-
-/**
- * xmem_cache_shrink - Shrink a cache.
- * @cachep: The cache to shrink.
- *
- * Releases as many slabs as possible for a cache.
- * To help debugging, a zero exit status indicates all slabs were released.
- */
-int xmem_cache_shrink(xmem_cache_t *cachep)
-{
- if (!cachep || !is_chained_xmem_cache(cachep))
- BUG();
-
- return __xmem_cache_shrink(cachep);
-}
-
-/**
- * xmem_cache_destroy - delete a cache
- * @cachep: the cache to destroy
- *
- * Remove a xmem_cache_t object from the slab cache.
- * Returns 0 on success.
- *
- * It is expected this function will be called by a module when it is
- * unloaded. This will remove the cache completely, and avoid a duplicate
- * cache being allocated each time a module is loaded and unloaded, if the
- * module doesn''t have persistent in-kernel storage across loads and
unloads.
- *
- * The caller must guarantee that noone will allocate memory from the cache
- * during the xmem_cache_destroy().
- */
-int xmem_cache_destroy (xmem_cache_t * cachep)
-{
- unsigned long spin_flags;
-
- if (!cachep || cachep->growing)
- BUG();
-
- /* Find the cache in the chain of caches. */
- down(&cache_chain_sem);
- /* the chain is never empty, cache_cache is never destroyed */
- if (clock_searchp == cachep)
- clock_searchp = list_entry(cachep->next.next,
- xmem_cache_t, next);
- list_del(&cachep->next);
- up(&cache_chain_sem);
-
- if (__xmem_cache_shrink(cachep)) {
- printk(KERN_ERR "xmem_cache_destroy: Can''t free all
objects %p\n",
- cachep);
- down(&cache_chain_sem);
- list_add(&cachep->next,&cache_chain);
- up(&cache_chain_sem);
- return 1;
- }
-#ifdef CONFIG_SMP
- {
- int i;
- for (i = 0; i < NR_CPUS; i++)
- xfree(cachep->cpudata[i]);
- }
-#endif
- xmem_cache_free(&cache_cache, cachep);
-
- return 0;
-}
-
-/* Get the memory for a slab management obj. */
-static inline slab_t *xmem_cache_slabmgmt(xmem_cache_t *cachep,
- void *objp, int colour_off,
- int local_flags)
-{
- slab_t *slabp;
-
- if (OFF_SLAB(cachep)) {
- /* Slab management obj is off-slab. */
- slabp = xmem_cache_alloc(cachep->slabp_cache);
- if (!slabp)
- return NULL;
- } else {
- /* FIXME: change to
- slabp = objp
- * if you enable OPTIMIZE
- */
- slabp = objp+colour_off;
- colour_off += L1_CACHE_ALIGN(cachep->num *
- sizeof(xmem_bufctl_t) + sizeof(slab_t));
- }
- slabp->inuse = 0;
- slabp->colouroff = colour_off;
- slabp->s_mem = objp+colour_off;
-
- return slabp;
-}
-
-static inline void xmem_cache_init_objs(xmem_cache_t *cachep,
- slab_t *slabp,
- unsigned long ctor_flags)
-{
- int i;
-
- for (i = 0; i < cachep->num; i++) {
- void* objp = slabp->s_mem+cachep->objsize*i;
-#if DEBUG
- if (cachep->flags & SLAB_RED_ZONE) {
- *((unsigned long*)(objp)) = RED_MAGIC1;
- *((unsigned long*)(objp + cachep->objsize -
- BYTES_PER_WORD)) = RED_MAGIC1;
- objp += BYTES_PER_WORD;
- }
-#endif
-
- /*
- * Constructors are not allowed to allocate memory from
- * the same cache which they are a constructor for.
- * Otherwise, deadlock. They must also be threaded.
- */
- if (cachep->ctor)
- cachep->ctor(objp, cachep, ctor_flags);
-#if DEBUG
- if (cachep->flags & SLAB_RED_ZONE)
- objp -= BYTES_PER_WORD;
- if (cachep->flags & SLAB_POISON)
- /* need to poison the objs */
- xmem_poison_obj(cachep, objp);
- if (cachep->flags & SLAB_RED_ZONE) {
- if (*((unsigned long*)(objp)) != RED_MAGIC1)
- BUG();
- if (*((unsigned long*)(objp + cachep->objsize -
- BYTES_PER_WORD)) != RED_MAGIC1)
- BUG();
- }
-#endif
- slab_bufctl(slabp)[i] = i+1;
- }
- slab_bufctl(slabp)[i-1] = BUFCTL_END;
- slabp->free = 0;
-}
-
-/*
- * Grow (by 1) the number of slabs within a cache. This is called by
- * xmem_cache_alloc() when there are no active objs left in a cache.
- */
-static int xmem_cache_grow(xmem_cache_t * cachep)
-{
- slab_t *slabp;
- struct pfn_info *page; unsigned int i;
- void *objp;
- size_t offset;
- unsigned long ctor_flags;
- unsigned long save_flags;
-
- ctor_flags = SLAB_CTOR_CONSTRUCTOR;
-
- /* About to mess with non-constant members - lock. */
- spin_lock_irqsave(&cachep->spinlock, save_flags);
-
- /* Get colour for the slab, and cal the next value. */
- offset = cachep->colour_next;
- cachep->colour_next++;
- if (cachep->colour_next >= cachep->colour)
- cachep->colour_next = 0;
- offset *= cachep->colour_off;
- cachep->dflags |= DFLGS_GROWN;
-
- cachep->growing++;
- spin_unlock_irqrestore(&cachep->spinlock, save_flags);
-
- /* A series of memory allocations for a new slab.
- * Neither the cache-chain semaphore, or cache-lock, are
- * held, but the incrementing c_growing prevents this
- * cache from being reaped or shrunk.
- * Note: The cache could be selected in for reaping in
- * xmem_cache_reap(), but when the final test is made the
- * growing value will be seen.
- */
-
- /* Get mem for the objs. */
- if (!(objp = xmem_getpages(cachep)))
- goto failed;
-
- /* Get slab management. */
- if (!(slabp = xmem_cache_slabmgmt(cachep, objp, offset, 0)))
- goto opps1;
-
- /* Nasty!!!!!! I hope this is OK. */
- i = 1 << cachep->gfporder;
- page = virt_to_page(objp);
- do {
- SET_PAGE_CACHE(page, cachep);
- SET_PAGE_SLAB(page, slabp);
- PageSetSlab(page);
- page++;
- } while (--i);
-
- xmem_cache_init_objs(cachep, slabp, ctor_flags);
-
- spin_lock_irqsave(&cachep->spinlock, save_flags);
- cachep->growing--;
-
- /* Make slab active. */
- list_add_tail(&slabp->list, &cachep->slabs_free);
- STATS_INC_GROWN(cachep);
- cachep->failures = 0;
-
- spin_unlock_irqrestore(&cachep->spinlock, save_flags);
- return 1;
- opps1:
- xmem_freepages(cachep, objp);
- failed:
- spin_lock_irqsave(&cachep->spinlock, save_flags);
- cachep->growing--;
- spin_unlock_irqrestore(&cachep->spinlock, save_flags);
- return 0;
-}
-
-/*
- * Perform extra freeing checks:
- * - detect double free
- * - detect bad pointers.
- * Called with the cache-lock held.
- */
-
-#if DEBUG
-static int xmem_extra_free_checks (xmem_cache_t * cachep,
- slab_t *slabp, void * objp)
-{
- int i;
- unsigned int objnr = (objp-slabp->s_mem)/cachep->objsize;
-
- if (objnr >= cachep->num)
- BUG();
- if (objp != slabp->s_mem + objnr*cachep->objsize)
- BUG();
-
- /* Check slab''s freelist to see if this obj is there. */
- for (i = slabp->free; i != BUFCTL_END; i = slab_bufctl(slabp)[i]) {
- if (i == objnr)
- BUG();
- }
- return 0;
-}
-#endif
-
-static inline void * xmem_cache_alloc_one_tail (xmem_cache_t *cachep,
- slab_t *slabp)
-{
- void *objp;
-
- STATS_INC_ALLOCED(cachep);
- STATS_INC_ACTIVE(cachep);
- STATS_SET_HIGH(cachep);
-
- /* get obj pointer */
- slabp->inuse++;
- objp = slabp->s_mem + slabp->free*cachep->objsize;
- slabp->free=slab_bufctl(slabp)[slabp->free];
-
- if (unlikely(slabp->free == BUFCTL_END)) {
- list_del(&slabp->list);
- list_add(&slabp->list, &cachep->slabs_full);
- }
-#if DEBUG
- if (cachep->flags & SLAB_POISON)
- if (xmem_check_poison_obj(cachep, objp))
- BUG();
- if (cachep->flags & SLAB_RED_ZONE) {
- /* Set alloc red-zone, and check old one. */
- if (xchg((unsigned long *)objp, RED_MAGIC2) !- RED_MAGIC1)
- BUG();
- if (xchg((unsigned long *)(objp+cachep->objsize -
- BYTES_PER_WORD), RED_MAGIC2) != RED_MAGIC1)
- BUG();
- objp += BYTES_PER_WORD;
- }
-#endif
- return objp;
-}
-
-/*
- * Returns a ptr to an obj in the given cache.
- * caller must guarantee synchronization
- * #define for the goto optimization 8-)
- */
-#define xmem_cache_alloc_one(cachep) \
-({ \
- struct list_head * slabs_partial, * entry; \
- slab_t *slabp; \
- \
- slabs_partial = &(cachep)->slabs_partial; \
- entry = slabs_partial->next; \
- if (unlikely(entry == slabs_partial)) { \
- struct list_head * slabs_free; \
- slabs_free = &(cachep)->slabs_free; \
- entry = slabs_free->next; \
- if (unlikely(entry == slabs_free)) \
- goto alloc_new_slab; \
- list_del(entry); \
- list_add(entry, slabs_partial); \
- } \
- \
- slabp = list_entry(entry, slab_t, list); \
- xmem_cache_alloc_one_tail(cachep, slabp); \
-})
-
-#ifdef CONFIG_SMP
-void* xmem_cache_alloc_batch(xmem_cache_t* cachep)
-{
- int batchcount = cachep->batchcount;
- cpucache_t* cc = cc_data(cachep);
-
- spin_lock(&cachep->spinlock);
- while (batchcount--) {
- struct list_head * slabs_partial, * entry;
- slab_t *slabp;
- /* Get slab alloc is to come from. */
- slabs_partial = &(cachep)->slabs_partial;
- entry = slabs_partial->next;
- if (unlikely(entry == slabs_partial)) {
- struct list_head * slabs_free;
- slabs_free = &(cachep)->slabs_free;
- entry = slabs_free->next;
- if (unlikely(entry == slabs_free))
- break;
- list_del(entry);
- list_add(entry, slabs_partial);
- }
-
- slabp = list_entry(entry, slab_t, list);
- cc_entry(cc)[cc->avail++] -
xmem_cache_alloc_one_tail(cachep, slabp);
- }
- spin_unlock(&cachep->spinlock);
-
- if (cc->avail)
- return cc_entry(cc)[--cc->avail];
- return NULL;
-}
-#endif
-
-static inline void *__xmem_cache_alloc(xmem_cache_t *cachep)
-{
- unsigned long flags;
- void* objp;
-
- try_again:
- local_irq_save(flags);
-#ifdef CONFIG_SMP
- {
- cpucache_t *cc = cc_data(cachep);
-
- if (cc) {
- if (cc->avail) {
- STATS_INC_ALLOCHIT(cachep);
- objp = cc_entry(cc)[--cc->avail];
- } else {
- STATS_INC_ALLOCMISS(cachep);
- objp = xmem_cache_alloc_batch(cachep);
- if (!objp)
- goto alloc_new_slab_nolock;
- }
- } else {
- spin_lock(&cachep->spinlock);
- objp = xmem_cache_alloc_one(cachep);
- spin_unlock(&cachep->spinlock);
- }
- }
-#else
- objp = xmem_cache_alloc_one(cachep);
-#endif
- local_irq_restore(flags);
- return objp;
- alloc_new_slab:
-#ifdef CONFIG_SMP
- spin_unlock(&cachep->spinlock);
- alloc_new_slab_nolock:
-#endif
- local_irq_restore(flags);
- if (xmem_cache_grow(cachep))
- /* Someone may have stolen our objs. Doesn''t matter,
we''ll
- * just come back here again.
- */
- goto try_again;
- return NULL;
-}
-
-/*
- * Release an obj back to its cache. If the obj has a constructed
- * state, it should be in this state _before_ it is released.
- * - caller is responsible for the synchronization
- */
-
-#if DEBUG
-# define CHECK_NR(pg) \
- do { \
- if (!VALID_PAGE(pg)) { \
- printk(KERN_ERR "xfree: out of range ptr %lxh.\n", \
- (unsigned long)objp); \
- BUG(); \
- } \
- } while (0)
-# define CHECK_PAGE(page) \
- do { \
- CHECK_NR(page); \
- if (!PageSlab(page)) { \
- printk(KERN_ERR "xfree: bad ptr %lxh.\n", \
- (unsigned long)objp); \
- BUG(); \
- } \
- } while (0)
-
-#else
-# define CHECK_PAGE(pg) do { } while (0)
-#endif
-
-static inline void xmem_cache_free_one(xmem_cache_t *cachep, void *objp)
-{
- slab_t* slabp;
-
- CHECK_PAGE(virt_to_page(objp));
- /* reduces memory footprint
- *
- if (OPTIMIZE(cachep))
- slabp = (void*)((unsigned long)objp&(~(PAGE_SIZE-1)));
- else
- */
- slabp = GET_PAGE_SLAB(virt_to_page(objp));
-
-#if DEBUG
- if (cachep->flags & SLAB_DEBUG_INITIAL)
- /* Need to call the slab''s constructor so the
- * caller can perform a verify of its state (debugging).
- * Called without the cache-lock held.
- */
- cachep->ctor(objp, cachep, SLAB_CTOR_CONSTRUCTOR|SLAB_CTOR_VERIFY);
-
- if (cachep->flags & SLAB_RED_ZONE) {
- objp -= BYTES_PER_WORD;
- if (xchg((unsigned long *)objp, RED_MAGIC1) != RED_MAGIC2)
- /* Either write before start, or a double free. */
- BUG();
- if (xchg((unsigned long *)(objp+cachep->objsize -
- BYTES_PER_WORD), RED_MAGIC1) != RED_MAGIC2)
- /* Either write past end, or a double free. */
- BUG();
- }
- if (cachep->flags & SLAB_POISON)
- xmem_poison_obj(cachep, objp);
- if (xmem_extra_free_checks(cachep, slabp, objp))
- return;
-#endif
- {
- unsigned int objnr = (objp-slabp->s_mem)/cachep->objsize;
-
- slab_bufctl(slabp)[objnr] = slabp->free;
- slabp->free = objnr;
- }
- STATS_DEC_ACTIVE(cachep);
-
- /* fixup slab chains */
- {
- int inuse = slabp->inuse;
- if (unlikely(!--slabp->inuse)) {
- /* Was partial or full, now empty. */
- list_del(&slabp->list);
- list_add(&slabp->list, &cachep->slabs_free);
- } else if (unlikely(inuse == cachep->num)) {
- /* Was full. */
- list_del(&slabp->list);
- list_add(&slabp->list, &cachep->slabs_partial);
- }
- }
-}
-
-#ifdef CONFIG_SMP
-static inline void __free_block (xmem_cache_t* cachep,
- void** objpp, int len)
-{
- for ( ; len > 0; len--, objpp++)
- xmem_cache_free_one(cachep, *objpp);
-}
-
-static void free_block (xmem_cache_t* cachep, void** objpp, int len)
-{
- spin_lock(&cachep->spinlock);
- __free_block(cachep, objpp, len);
- spin_unlock(&cachep->spinlock);
-}
-#endif
-
-/*
- * __xmem_cache_free
- * called with disabled ints
- */
-static inline void __xmem_cache_free (xmem_cache_t *cachep, void* objp)
-{
-#ifdef CONFIG_SMP
- cpucache_t *cc = cc_data(cachep);
-
- CHECK_PAGE(virt_to_page(objp));
- if (cc) {
- int batchcount;
- if (cc->avail < cc->limit) {
- STATS_INC_FREEHIT(cachep);
- cc_entry(cc)[cc->avail++] = objp;
- return;
- }
- STATS_INC_FREEMISS(cachep);
- batchcount = cachep->batchcount;
- cc->avail -= batchcount;
- free_block(cachep,
- &cc_entry(cc)[cc->avail],batchcount);
- cc_entry(cc)[cc->avail++] = objp;
- return;
- } else {
- free_block(cachep, &objp, 1);
- }
-#else
- xmem_cache_free_one(cachep, objp);
-#endif
-}
-
-/**
- * xmem_cache_alloc - Allocate an object
- * @cachep: The cache to allocate from.
- *
- * Allocate an object from this cache. The flags are only relevant
- * if the cache has no available objects.
- */
-void *xmem_cache_alloc(xmem_cache_t *cachep)
-{
- return __xmem_cache_alloc(cachep);
-}
-
-/**
- * xmalloc - allocate memory
- * @size: how many bytes of memory are required.
- */
-void *xmalloc(size_t size)
-{
- cache_sizes_t *csizep = cache_sizes;
-
- for (; csizep->cs_size; csizep++) {
- if (size > csizep->cs_size)
- continue;
- return __xmem_cache_alloc(csizep->cs_cachep);
- }
- return NULL;
-}
-
-/**
- * xmem_cache_free - Deallocate an object
- * @cachep: The cache the allocation was from.
- * @objp: The previously allocated object.
- *
- * Free an object which was previously allocated from this
- * cache.
- */
-void xmem_cache_free (xmem_cache_t *cachep, void *objp)
-{
- unsigned long flags;
-#if DEBUG
- CHECK_PAGE(virt_to_page(objp));
- if (cachep != GET_PAGE_CACHE(virt_to_page(objp)))
- BUG();
-#endif
-
- local_irq_save(flags);
- __xmem_cache_free(cachep, objp);
- local_irq_restore(flags);
-}
-
-/**
- * xfree - free previously allocated memory
- * @objp: pointer returned by xmalloc.
- *
- * Don''t free memory not originally allocated by xmalloc()
- * or you will run into trouble.
- */
-void xfree (const void *objp)
-{
- xmem_cache_t *c;
- unsigned long flags;
-
- if (!objp)
- return;
- local_irq_save(flags);
- CHECK_PAGE(virt_to_page(objp));
- c = GET_PAGE_CACHE(virt_to_page(objp));
- __xmem_cache_free(c, (void*)objp);
- local_irq_restore(flags);
-}
-
-xmem_cache_t *xmem_find_general_cachep(size_t size)
-{
- cache_sizes_t *csizep = cache_sizes;
-
- /* This function could be moved to the header file, and
- * made inline so consumers can quickly determine what
- * cache pointer they require.
- */
- for ( ; csizep->cs_size; csizep++) {
- if (size > csizep->cs_size)
- continue;
- break;
- }
- return csizep->cs_cachep;
-}
-
-#ifdef CONFIG_SMP
-
-/* called with cache_chain_sem acquired. */
-static int xmem_tune_cpucache (xmem_cache_t* cachep, int limit, int batchcount)
-{
- ccupdate_struct_t new;
- int i;
-
- /*
- * These are admin-provided, so we are more graceful.
- */
- if (limit < 0)
- return -EINVAL;
- if (batchcount < 0)
- return -EINVAL;
- if (batchcount > limit)
- return -EINVAL;
- if (limit != 0 && !batchcount)
- return -EINVAL;
-
- memset(&new.new,0,sizeof(new.new));
- if (limit) {
- for (i = 0; i< smp_num_cpus; i++) {
- cpucache_t* ccnew;
-
- ccnew = xmalloc(sizeof(void*)*limit+sizeof(cpucache_t));
- if (!ccnew)
- goto oom;
- ccnew->limit = limit;
- ccnew->avail = 0;
- new.new[cpu_logical_map(i)] = ccnew;
- }
- }
- new.cachep = cachep;
- spin_lock_irq(&cachep->spinlock);
- cachep->batchcount = batchcount;
- spin_unlock_irq(&cachep->spinlock);
-
- smp_call_function_all_cpus(do_ccupdate_local, (void *)&new);
-
- for (i = 0; i < smp_num_cpus; i++) {
- cpucache_t* ccold = new.new[cpu_logical_map(i)];
- if (!ccold)
- continue;
- local_irq_disable();
- free_block(cachep, cc_entry(ccold), ccold->avail);
- local_irq_enable();
- xfree(ccold);
- }
- return 0;
- oom:
- for (i--; i >= 0; i--)
- xfree(new.new[cpu_logical_map(i)]);
- return -ENOMEM;
-}
-
-static void enable_cpucache (xmem_cache_t *cachep)
-{
- int err;
- int limit;
-
- /* FIXME: optimize */
- if (cachep->objsize > PAGE_SIZE)
- return;
- if (cachep->objsize > 1024)
- limit = 60;
- else if (cachep->objsize > 256)
- limit = 124;
- else
- limit = 252;
-
- err = xmem_tune_cpucache(cachep, limit, limit/2);
- if (err)
- printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n",
- cachep->name, -err);
-}
-
-static void enable_all_cpucaches (void)
-{
- struct list_head* p;
- unsigned long spin_flags;
-
- down(&cache_chain_sem);
-
- p = &cache_cache.next;
- do {
- xmem_cache_t* cachep = list_entry(p, xmem_cache_t, next);
-
- enable_cpucache(cachep);
- p = cachep->next.next;
- } while (p != &cache_cache.next);
-
- up(&cache_chain_sem);
-}
-#endif
-
-/**
- * xmem_cache_reap - Reclaim memory from caches.
- */
-int xmem_cache_reap(void)
-{
- slab_t *slabp;
- xmem_cache_t *searchp;
- xmem_cache_t *best_cachep;
- unsigned int best_pages;
- unsigned int best_len;
- unsigned int scan;
- int ret = 0;
- unsigned long spin_flags;
-
- down(&cache_chain_sem);
-
- scan = REAP_SCANLEN;
- best_len = 0;
- best_pages = 0;
- best_cachep = NULL;
- searchp = clock_searchp;
- do {
- unsigned int pages;
- struct list_head* p;
- unsigned int full_free;
-
- /* It''s safe to test this without holding the cache-lock. */
- if (searchp->flags & SLAB_NO_REAP)
- goto next;
- spin_lock_irq(&searchp->spinlock);
- if (searchp->growing)
- goto next_unlock;
- if (searchp->dflags & DFLGS_GROWN) {
- searchp->dflags &= ~DFLGS_GROWN;
- goto next_unlock;
- }
-#ifdef CONFIG_SMP
- {
- cpucache_t *cc = cc_data(searchp);
- if (cc && cc->avail) {
- __free_block(searchp, cc_entry(cc), cc->avail);
- cc->avail = 0;
- }
- }
-#endif
-
- full_free = 0;
- p = searchp->slabs_free.next;
- while (p != &searchp->slabs_free) {
- slabp = list_entry(p, slab_t, list);
-#if DEBUG
- if (slabp->inuse)
- BUG();
-#endif
- full_free++;
- p = p->next;
- }
-
- /*
- * Try to avoid slabs with constructors and/or
- * more than one page per slab (as it can be difficult
- * to get high orders from gfp()).
- */
- pages = full_free * (1<<searchp->gfporder);
- if (searchp->ctor)
- pages = (pages*4+1)/5;
- if (searchp->gfporder)
- pages = (pages*4+1)/5;
- if (pages > best_pages) {
- best_cachep = searchp;
- best_len = full_free;
- best_pages = pages;
- if (pages >= REAP_PERFECT) {
- clock_searchp = list_entry(searchp->next.next,
- xmem_cache_t,next);
- goto perfect;
- }
- }
- next_unlock:
- spin_unlock_irq(&searchp->spinlock);
- next:
- searchp = list_entry(searchp->next.next,xmem_cache_t,next);
- } while (--scan && searchp != clock_searchp);
-
- clock_searchp = searchp;
-
- if (!best_cachep)
- /* couldn''t find anything to reap */
- goto out;
-
- spin_lock_irq(&best_cachep->spinlock);
- perfect:
- /* free only 50% of the free slabs */
- best_len = (best_len + 1)/2;
- for (scan = 0; scan < best_len; scan++) {
- struct list_head *p;
-
- if (best_cachep->growing)
- break;
- p = best_cachep->slabs_free.prev;
- if (p == &best_cachep->slabs_free)
- break;
- slabp = list_entry(p,slab_t,list);
-#if DEBUG
- if (slabp->inuse)
- BUG();
-#endif
- list_del(&slabp->list);
- STATS_INC_REAPED(best_cachep);
-
- /* Safe to drop the lock. The slab is no longer linked to the
- * cache.
- */
- spin_unlock_irq(&best_cachep->spinlock);
- xmem_slab_destroy(best_cachep, slabp);
- spin_lock_irq(&best_cachep->spinlock);
- }
- spin_unlock_irq(&best_cachep->spinlock);
- ret = scan * (1 << best_cachep->gfporder);
- out:
- up(&cache_chain_sem);
- return ret;
-}
-
-void dump_slabinfo()
-{
- struct list_head *p;
- unsigned long spin_flags;
-
- /* Output format version, so at least we can change it without _too_
- * many complaints.
- */
- printk( "slabinfo - version: 1.1"
-#if STATS
- " (statistics)"
-#endif
-#ifdef CONFIG_SMP
- " (SMP)"
-#endif
- "\n");
- down(&cache_chain_sem);
- p = &cache_cache.next;
- do {
- xmem_cache_t *cachep;
- slab_t *slabp;
- unsigned long active_objs;
- unsigned long num_objs;
- unsigned long active_slabs = 0;
- unsigned long num_slabs;
- cachep = list_entry(p, xmem_cache_t, next);
-
- spin_lock_irq(&cachep->spinlock);
- active_objs = 0;
- num_slabs = 0;
- list_for_each_entry(slabp, &cachep->slabs_full, list) {
- if (slabp->inuse != cachep->num)
- BUG();
- active_objs += cachep->num;
- active_slabs++;
- }
- list_for_each_entry(slabp, &cachep->slabs_partial, list) {
- if (slabp->inuse == cachep->num || !slabp->inuse)
- BUG();
- active_objs += slabp->inuse;
- active_slabs++;
- }
- list_for_each_entry(slabp, &cachep->slabs_free, list) {
- if (slabp->inuse)
- BUG();
- num_slabs++;
- }
- num_slabs+=active_slabs;
- num_objs = num_slabs*cachep->num;
-
- printk("%-17s %6lu %6lu %6u %4lu %4lu %4u",
- cachep->name, active_objs, num_objs, cachep->objsize,
- active_slabs, num_slabs, (1<<cachep->gfporder));
-
-#if STATS
- {
- unsigned long errors = cachep->errors;
- unsigned long high = cachep->high_mark;
- unsigned long grown = cachep->grown;
- unsigned long reaped = cachep->reaped;
- unsigned long allocs = cachep->num_allocations;
-
- printk(" : %6lu %7lu %5lu %4lu %4lu",
- high, allocs, grown, reaped, errors);
- }
-#endif
-#ifdef CONFIG_SMP
- {
- unsigned int batchcount = cachep->batchcount;
- unsigned int limit;
-
- if (cc_data(cachep))
- limit = cc_data(cachep)->limit;
- else
- limit = 0;
- printk(" : %4u %4u",
- limit, batchcount);
- }
-#endif
-#if STATS && defined(CONFIG_SMP)
- {
- unsigned long allochit = atomic_read(&cachep->allochit);
- unsigned long allocmiss = atomic_read(&cachep->allocmiss);
- unsigned long freehit = atomic_read(&cachep->freehit);
- unsigned long freemiss = atomic_read(&cachep->freemiss);
- printk(" : %6lu %6lu %6lu %6lu",
- allochit, allocmiss, freehit, freemiss);
- }
-#endif
- printk("\n");
- spin_unlock_irq(&cachep->spinlock);
-
- p = cachep->next.next;
- } while (p != &cache_cache.next);
-
- up(&cache_chain_sem);
-
- return;
-}
diff -urpN --exclude TAGS -X
/home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal
xen-unstable-pre/xen/include/xen/domain.h
xen-unstable-working/xen/include/xen/domain.h
--- xen-unstable-pre/xen/include/xen/domain.h 2005-01-30 15:28:47.000000000
+1100
+++ xen-unstable-working/xen/include/xen/domain.h 2005-02-01 16:57:17.000000000
+1100
@@ -6,8 +6,6 @@
* Arch-specifics.
*/
-extern void domain_startofday(void);
-
extern struct domain *arch_alloc_domain_struct(void);
extern void arch_free_domain_struct(struct domain *d);
diff -urpN --exclude TAGS -X
/home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal
xen-unstable-pre/xen/include/xen/lib.h
xen-unstable-working/xen/include/xen/lib.h
--- xen-unstable-pre/xen/include/xen/lib.h 2005-01-30 15:28:55.000000000 +1100
+++ xen-unstable-working/xen/include/xen/lib.h 2005-02-01 16:57:17.000000000
+1100
@@ -20,6 +20,18 @@ struct domain;
void cmdline_parse(char *cmdline);
+/**
+ * container_of - cast a member of a structure out to the containing structure
+ *
+ * @ptr: the pointer to the member.
+ * @type: the type of the container struct this is embedded in.
+ * @member: the name of the member within the struct.
+ *
+ */
+#define container_of(ptr, type, member) ({ \
+ const typeof( ((type *)0)->member ) *__mptr = (ptr); \
+ (type *)( (char *)__mptr - offsetof(type,member) );})
+
#define printk printf
void printf(const char *format, ...);
void panic(const char *format, ...);
diff -urpN --exclude TAGS -X
/home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal
xen-unstable-pre/xen/include/xen/list.h
xen-unstable-working/xen/include/xen/list.h
--- xen-unstable-pre/xen/include/xen/list.h 2005-01-30 15:28:50.000000000 +1100
+++ xen-unstable-working/xen/include/xen/list.h 2005-02-01 16:57:17.000000000
+1100
@@ -174,5 +174,17 @@ static __inline__ void list_splice(struc
pos = list_entry(pos->member.next, typeof(*pos), member), \
prefetch(pos->member.next))
+/**
+ * list_for_each_entry_safe - iterate over list of given type safe against
removal of list entry
+ * @pos: the type * to use as a loop counter.
+ * @n: another type * to use as temporary storage
+ * @head: the head for your list.
+ * @member: the name of the list_struct within the struct.
+ */
+#define list_for_each_entry_safe(pos, n, head, member) \
+ for (pos = list_entry((head)->next, typeof(*pos), member), \
+ n = list_entry(pos->member.next, typeof(*pos), member); \
+ &pos->member != (head); \
+ pos = n, n = list_entry(n->member.next, typeof(*n), member))
#endif /* _LINUX_LIST_H */
diff -urpN --exclude TAGS -X
/home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal
xen-unstable-pre/xen/include/xen/slab.h
xen-unstable-working/xen/include/xen/slab.h
--- xen-unstable-pre/xen/include/xen/slab.h 2005-02-02 16:01:49.000000000 +1100
+++ xen-unstable-working/xen/include/xen/slab.h 2005-02-02 16:19:39.000000000
+1100
@@ -13,45 +13,14 @@
#include <asm/slab.h>
#else
-
-typedef struct xmem_cache_s xmem_cache_t;
-
#include <xen/mm.h>
#include <xen/cache.h>
#include <xen/types.h>
-/* Flags to pass to xmem_cache_create(). */
-/* NB. The first 3 are only valid when built with SLAB_DEBUG_SUPPORT. */
-#define SLAB_DEBUG_INITIAL 0x00000200UL /* Call constructor */
-#define SLAB_RED_ZONE 0x00000400UL /* Red zone objs in a cache */
-#define SLAB_POISON 0x00000800UL /* Poison objects */
-#define SLAB_NO_REAP 0x00001000UL /* never reap from the cache */
-#define SLAB_HWCACHE_ALIGN 0x00002000UL /* align obj on a cache line */
-
-/* Flags passed to a constructor function. */
-#define SLAB_CTOR_CONSTRUCTOR 0x001UL /* if not set, then deconstructor */
-#define SLAB_CTOR_ATOMIC 0x002UL /* tell cons. it can''t sleep
*/
-#define SLAB_CTOR_VERIFY 0x004UL /* tell cons. it''s a verify
call */
-
-extern void xmem_cache_init(void);
-extern void xmem_cache_sizes_init(unsigned long);
-
-extern xmem_cache_t *xmem_find_general_cachep(size_t);
-extern xmem_cache_t *xmem_cache_create(
- const char *, size_t, size_t, unsigned long,
- void (*)(void *, xmem_cache_t *, unsigned long),
- void (*)(void *, xmem_cache_t *, unsigned long));
-extern int xmem_cache_destroy(xmem_cache_t *);
-extern int xmem_cache_shrink(xmem_cache_t *);
-extern void *xmem_cache_alloc(xmem_cache_t *);
-extern void xmem_cache_free(xmem_cache_t *, void *);
-
-extern void *xmalloc(size_t);
-extern void xfree(const void *);
-
-extern int xmem_cache_reap(void);
-
-extern void dump_slabinfo();
+#define xmalloc(size) __xmalloc(size, __FILE__, __LINE__)
+#define xfree(ptr) __xfree(ptr, __FILE__, __LINE__)
+extern void *__xmalloc(size_t size, const char *file, unsigned int line);
+extern void __xfree(const void *p, const char *file, unsigned int line);
/* Nicely typesafe for you. */
#define new(type) ((type *)xmalloc(sizeof(type)))
--
A bad analogy is like a leaky screwdriver -- Richard Braakman
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Ian Pratt
2005-Feb-02 16:19 UTC
Re: [Xen-devel] [PATCH 3/3] Replace slab.c with a very simple allocator.
> slab.c in Linux is not a very nice piece of code: the version in Xen has > been hacked a certain amount and is not a vision of beauty either. > > Given how rare and non-time-critical dynamic allocations are in Xen, > this replaces the 1800-line slab.c with a 160-line malloc.c which is > written as simply as possible for future enhancement. > > Tested in userspace, boots Xen fine.Rusty, This turns out to be an oversimplification -- it doesn''t boot for me as exec_domain''s aren''t 16 byte aligned and hence fxsave fails. I think we want to ensure that the object returned is always aligned to start on a L1 cache line boundary. I don''t care that we burn some memory as we don''t have lots of small allocs. Please could you adjust your patch having resync''ed from usntable. Thanks, Ian ------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
Rusty Russell
2005-Feb-03 00:51 UTC
Re: [Xen-devel] [PATCH 3/3] Replace slab.c with a very simple allocator.
On Wed, 2005-02-02 at 16:19 +0000, Ian Pratt wrote:> > slab.c in Linux is not a very nice piece of code: the version in Xen has > > been hacked a certain amount and is not a vision of beauty either. > > > > Given how rare and non-time-critical dynamic allocations are in Xen, > > this replaces the 1800-line slab.c with a 160-line malloc.c which is > > written as simply as possible for future enhancement. > > > > Tested in userspace, boots Xen fine. > > Rusty, > > This turns out to be an oversimplification -- it doesn''t boot for > me as exec_domain''s aren''t 16 byte aligned and hence fxsave > fails.Damn, apologies for missing this requirement. Good catch.> I think we want to ensure that the object returned is always > aligned to start on a L1 cache line boundary. I don''t care that > we burn some memory as we don''t have lots of small allocs.If I may suggest, I''d prefer to put this in the hands of the caller, with an explicit alignment arg. This simply falls out with this type-safe versions using __alignof__, and should neatly document this requirement, for example.> Please could you adjust your patch having resync''ed from usntable.Hmm, I hope that the bk snapshot is close enough. Will do, Rusty. -- A bad analogy is like a leaky screwdriver -- Richard Braakman ------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel