From: Andi Kleen <ak@muc.de>
To: torvalds@transmeta.com
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] Slab cache name fixes / reiserfs boot bug fix.
Date: Thu, 31 Jan 2002 00:29:37 +0100 [thread overview]
Message-ID: <20020131002937.A1372@averell> (raw)
Hi Linus,
As discussed earlier this patch cleans up the way the names of slab
caches are stored. The caller is now expected to keep the storage,
instead of copying and arbitarily imposing a name length limit on the
slab names. This fixes the reiserfs boot time BUG() that is still in 2.5.3.
I had to fix some callers that were creating cache names on the stack,
that is why the patch is a bit larger.
I didn't audit the complete tree that modules do always destroy their caches
on unloading, when they do not do it this patch will hopefully detect it
on the next cat /proc/slabinfo (and otherwise not care as it was the situation
before).
I addressed all the criticisms that came to earlier versions of the patch,
except for the one that proposed to "strdup" the name because that would have
needed a custom allocator just for that (kmem_cache_create cannot use kmalloc)
Patch against 2.5.3. Please apply.
Thanks,
-Andi
--- linux-2.5.3-work/fs/bio.c-SLABNAME Tue Jan 15 17:53:31 2002
+++ linux-2.5.3-work/fs/bio.c Wed Jan 30 23:50:57 2002
@@ -45,6 +45,7 @@
* unsigned short
*/
static const int bvec_pool_sizes[BIOVEC_NR_POOLS] = { 1, 4, 16, 64, 128, 256 };
+static char bvec_pool_names[BIOVEC_NR_POOLS][16];
#define BIO_MAX_PAGES (bvec_pool_sizes[BIOVEC_NR_POOLS - 1])
@@ -452,20 +453,20 @@
static void __init biovec_init_pool(void)
{
- char name[16];
int i, size;
memset(&bvec_array, 0, sizeof(bvec_array));
for (i = 0; i < BIOVEC_NR_POOLS; i++) {
struct biovec_pool *bp = bvec_array + i;
+ char *name = bvec_pool_names[i];
size = bvec_pool_sizes[i] * sizeof(struct bio_vec);
printk("biovec: init pool %d, %d entries, %d bytes\n", i,
bvec_pool_sizes[i], size);
- snprintf(name, sizeof(name) - 1,"biovec-%d",bvec_pool_sizes[i]);
+ sprintf(name, "biovec-%d",bvec_pool_sizes[i]);
bp->slab = kmem_cache_create(name, size, 0,
SLAB_HWCACHE_ALIGN, NULL, NULL);
if (!bp->slab)
--- linux-2.5.3-work/mm/slab.c-SLABNAME Tue Jan 15 17:53:36 2002
+++ linux-2.5.3-work/mm/slab.c Thu Jan 31 00:22:13 2002
@@ -186,8 +186,6 @@
* manages a cache.
*/
-#define CACHE_NAMELEN 20 /* max name length for a slab cache */
-
struct kmem_cache_s {
/* 1) each alloc & free */
/* full, partial first, then free */
@@ -225,7 +223,7 @@
unsigned long failures;
/* 3) cache creation/removal */
- char name[CACHE_NAMELEN];
+ const char *name;
struct list_head next;
#ifdef CONFIG_SMP
/* 4) per-cpu data */
@@ -335,6 +333,7 @@
kmem_cache_t *cs_dmacachep;
} cache_sizes_t;
+/* These are the default caches for kmalloc. Custom caches can have other sizes. */
static cache_sizes_t cache_sizes[] = {
#if PAGE_SIZE == 4096
{ 32, NULL, NULL},
@@ -353,6 +352,26 @@
{131072, NULL, NULL},
{ 0, NULL, NULL}
};
+/* Must match cache_sizes above. Out of line to keep cache footprint low. */
+#define CN(x) { x, x " (DMA)" }
+static char cache_names[][2][18] = {
+#if PAGE_SIZE == 4096
+ CN("size-32"),
+#endif
+ CN("size-64"),
+ CN("size-128"),
+ CN("size-256"),
+ CN("size-512"),
+ CN("size-1024"),
+ CN("size-2048"),
+ CN("size-4096"),
+ CN("size-8192"),
+ CN("size-16384"),
+ CN("size-32768"),
+ CN("size-65536"),
+ CN("size-131072")
+};
+#undef CN
/* internal cache of cache description objs */
static kmem_cache_t cache_cache = {
@@ -437,7 +456,6 @@
void __init kmem_cache_sizes_init(void)
{
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.
@@ -450,9 +468,9 @@
* 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 =
- kmem_cache_create(name, sizes->cs_size,
+ kmem_cache_create(cache_names[sizes-cache_sizes][0],
+ sizes->cs_size,
0, SLAB_HWCACHE_ALIGN, NULL, NULL))) {
BUG();
}
@@ -462,9 +480,10 @@
offslab_limit = sizes->cs_size-sizeof(slab_t);
offslab_limit /= 2;
}
- sprintf(name, "size-%Zd(DMA)",sizes->cs_size);
- sizes->cs_dmacachep = kmem_cache_create(name, sizes->cs_size, 0,
- SLAB_CACHE_DMA|SLAB_HWCACHE_ALIGN, NULL, NULL);
+ sizes->cs_dmacachep = kmem_cache_create(
+ cache_names[sizes-cache_sizes][1],
+ sizes->cs_size, 0,
+ SLAB_CACHE_DMA|SLAB_HWCACHE_ALIGN, NULL, NULL);
if (!sizes->cs_dmacachep)
BUG();
sizes++;
@@ -604,6 +623,11 @@
* 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.
+ *
+ * @name must be valid until the cache is destroyed. This implies that
+ * the module calling this has to destroy the cache before getting
+ * unloaded.
+ *
* The flags are
*
* %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
@@ -632,7 +656,6 @@
* Sanity checks... these are all serious usage bugs.
*/
if ((!name) ||
- ((strlen(name) >= CACHE_NAMELEN - 1)) ||
in_interrupt() ||
(size < BYTES_PER_WORD) ||
(size > (1<<MAX_OBJ_ORDER)*PAGE_SIZE) ||
@@ -797,8 +820,7 @@
cachep->slabp_cache = kmem_find_general_cachep(slab_size,0);
cachep->ctor = ctor;
cachep->dtor = dtor;
- /* Copy name over so we don't have problems with unloaded modules */
- strcpy(cachep->name, name);
+ cachep->name = name;
#ifdef CONFIG_SMP
if (g_cpucache_up)
@@ -811,10 +833,20 @@
list_for_each(p, &cache_chain) {
kmem_cache_t *pc = list_entry(p, kmem_cache_t, next);
-
- /* The name field is constant - no lock needed. */
- if (!strcmp(pc->name, name))
- BUG();
+ char tmp;
+ /* This happens when the module gets unloaded and doesn't
+ destroy its slab cache and noone else reuses the vmalloc
+ area of the module. Print a warning. */
+ if (__get_user(tmp,pc->name)) {
+ printk("SLAB: cache with size %d has lost its name\n",
+ pc->objsize);
+ continue;
+ }
+ if (!strcmp(pc->name,name)) {
+ printk("kmem_cache_create: duplicate cache %s\n",name);
+ up(&cache_chain_sem);
+ BUG();
+ }
}
}
@@ -1878,6 +1910,7 @@
unsigned long num_objs;
unsigned long active_slabs = 0;
unsigned long num_slabs;
+ const char *name;
cachep = list_entry(p, kmem_cache_t, next);
spin_lock_irq(&cachep->spinlock);
@@ -1906,8 +1939,15 @@
num_slabs+=active_slabs;
num_objs = num_slabs*cachep->num;
+ name = cachep->name;
+ {
+ char tmp;
+ if (__get_user(tmp, name))
+ name = "broken";
+ }
+
len += sprintf(page+len, "%-17s %6lu %6lu %6u %4lu %4lu %4u",
- cachep->name, active_objs, num_objs, cachep->objsize,
+ name, active_objs, num_objs, cachep->objsize,
active_slabs, num_slabs, (1<<cachep->gfporder));
#if STATS
--- linux-2.5.3-work/include/net/neighbour.h-SLABNAME Wed Jan 30 22:44:34 2002
+++ linux-2.5.3-work/include/net/neighbour.h Wed Jan 30 23:37:54 2002
@@ -147,7 +147,7 @@
int (*pconstructor)(struct pneigh_entry *);
void (*pdestructor)(struct pneigh_entry *);
void (*proxy_redo)(struct sk_buff *skb);
- char *id;
+ char id[20];
struct neigh_parms parms;
/* HACK. gc_* shoul follow parms without a gap! */
int gc_interval;
--- linux-2.5.3-work/drivers/scsi/scsi.c-SLABNAME Tue Jan 15 17:53:29 2002
+++ linux-2.5.3-work/drivers/scsi/scsi.c Thu Jan 31 00:08:06 2002
@@ -93,6 +93,7 @@
static const int scsi_host_sg_pool_sizes[SG_MEMPOOL_NR] = { 8, 16, 32, 64, MAX_PHYS_SEGMENTS };
struct scsi_host_sg_pool scsi_sg_pools[SG_MEMPOOL_NR];
+static char scsi_host_sg_names[SG_MEMPOOL_NR][18];
/*
static const char RCSid[] = "$Header: /vger/u4/cvs/linux/drivers/scsi/scsi.c,v 1.38 1997/01/19 23:07:18 davem Exp $";
@@ -2489,7 +2490,6 @@
static int __init init_scsi(void)
{
struct proc_dir_entry *generic;
- char name[16];
int i;
printk(KERN_INFO "SCSI subsystem driver " REVISION "\n");
@@ -2498,10 +2498,11 @@
* setup sg memory pools
*/
for (i = 0; i < SG_MEMPOOL_NR; i++) {
+ char *name = scsi_host_sg_names[i];
struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
int size = scsi_host_sg_pool_sizes[i] * sizeof(struct scatterlist);
- snprintf(name, sizeof(name) - 1, "sgpool-%d", scsi_host_sg_pool_sizes[i]);
+ sprintf(name, "sgpool-%d", scsi_host_sg_pool_sizes[i]);
sgp->slab = kmem_cache_create(name, size, 0, SLAB_HWCACHE_ALIGN, NULL, NULL);
if (!sgp->slab)
panic("SCSI: can't init sg slab\n");
next reply other threads:[~2002-01-30 23:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-01-30 23:29 Andi Kleen [this message]
[not found] ` <Pine.LNX.4.33.0201301548100.14950-100000@penguin.transmeta.com>
2002-01-30 23:59 ` [PATCH] Slab cache name fixes / reiserfs boot bug fix Andi Kleen
2002-01-31 0:48 ` Andi Kleen
[not found] ` <20020131100219.A11046@namesys.com>
2002-01-31 16:08 ` Andi Kleen
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