Add support for aggregated beancounters. An aggregated beancounter contains
several beancounters. The default aggregator is called init_ab (similar to
init_bc). Aggregated beancounters are created without any limits imposed
on them.
Signed-off-by: Balbir Singh <[email protected]>
---
include/bc/beancounter.h | 48 +++++++-
kernel/bc/beancounter.c | 272 ++++++++++++++++++++++++++++++++++++++++-------
kernel/bc/misc.c | 2
3 files changed, 280 insertions(+), 42 deletions(-)
diff -puN include/bc/beancounter.h~add-aggr-bc include/bc/beancounter.h
--- linux-2.6.18-rc5/include/bc/beancounter.h~add-aggr-bc 2006-09-17 20:33:15.000000000 +0530
+++ linux-2.6.18-rc5-balbir/include/bc/beancounter.h 2006-09-17 20:33:15.000000000 +0530
@@ -18,6 +18,13 @@
#define BC_RESOURCES 3
+struct ab_resource_parm {
+ unsigned long barrier;
+ unsigned long held;
+ unsigned long limit; /* hard resource limit */
+ unsigned long failcnt; /* count of failed charges */
+};
+
struct bc_resource_parm {
unsigned long barrier; /* A barrier over which resource allocations
* are failed gracefully. e.g. if the amount
@@ -51,6 +58,27 @@ struct bc_resource_parm {
*/
#define BC_MAGIC 0x62756275UL
+#define AB_HASH_BITS 8
+#define AB_HASH_SIZE (1 << AB_HASH_BITS)
+#define ab_hash_fn(bcid) (hash_long(bcid, AB_HASH_BITS))
+
+#define BC_HASH_BITS 5
+#define BC_HASH_SIZE (1 << BC_HASH_BITS)
+#define bc_hash_fn(bcid) (hash_long(bcid, BC_HASH_BITS))
+
+
+/*
+ * Aggregate beancounters - group independent BC's together to form groups
+ */
+struct aggr_beancounter {
+ struct ab_resource_parm ab_parms[BC_RESOURCES];
+ atomic_t ab_refcount;
+ struct hlist_head ab_bucket[AB_HASH_SIZE];
+ spinlock_t ab_lock;
+ struct hlist_node hash;
+ bcid_t ab_id;
+};
+
/*
* Resource management structures
* Serialization issues:
@@ -73,6 +101,7 @@ struct beancounter {
#endif
/* resources statistics and settings */
struct bc_resource_parm bc_parms[BC_RESOURCES];
+ struct aggr_beancounter *ab;
};
enum bc_severity { BC_BARRIER, BC_LIMIT, BC_FORCE };
@@ -118,7 +147,20 @@ int __must_check bc_charge(struct beanco
void bc_uncharge_locked(struct beancounter *bc, int res, unsigned long val);
void bc_uncharge(struct beancounter *bc, int res, unsigned long val);
-struct beancounter *beancounter_findcreate(bcid_t id, int mask);
+struct beancounter *beancounter_create(struct aggr_beancounter *ab, bcid_t id);
+struct beancounter *beancounter_find_locked(struct aggr_beancounter *ab,
+ bcid_t id);
+struct aggr_beancounter *ab_findcreate(bcid_t id, int mask);
+struct beancounter *beancounter_relocate(struct aggr_beancounter *dst_ab,
+ struct aggr_beancounter *src_ab,
+ bcid_t id);
+
+static inline struct aggr_beancounter *
+get_aggr_beancounter(struct aggr_beancounter *ab)
+{
+ atomic_inc(&ab->ab_refcount);
+ return ab;
+}
static inline struct beancounter *get_beancounter(struct beancounter *bc)
{
@@ -127,6 +169,7 @@ static inline struct beancounter *get_be
}
void put_beancounter(struct beancounter *bc);
+void put_aggr_beancounter(struct aggr_beancounter *ab);
void bc_init_early(void);
void bc_init_late(void);
@@ -139,7 +182,8 @@ extern const char *bc_rnames[];
#define nr_beancounters 0
-#define beancounter_findcreate(id, f) (NULL)
+#define beancounter_create(ab, id) (NULL)
+#define beancounter_find_locked(ab, id) (NULL)
#define get_beancounter(bc) (NULL)
#define put_beancounter(bc) do { } while (0)
diff -puN kernel/bc/beancounter.c~add-aggr-bc kernel/bc/beancounter.c
--- linux-2.6.18-rc5/kernel/bc/beancounter.c~add-aggr-bc 2006-09-17 20:33:15.000000000 +0530
+++ linux-2.6.18-rc5-balbir/kernel/bc/beancounter.c 2006-09-17 20:33:15.000000000 +0530
@@ -14,11 +14,17 @@
#include <bc/vmrss.h>
static kmem_cache_t *bc_cachep;
+static kmem_cache_t *ab_cachep;
static struct beancounter default_beancounter;
-static void init_beancounter_struct(struct beancounter *bc, bcid_t id);
+static void init_beancounter_struct(struct aggr_beancounter *ab,
+ struct beancounter *bc, bcid_t id);
+static void init_aggr_beancounter_struct(struct aggr_beancounter *ab,
+ bcid_t id);
+static void init_aggr_beancounter_parm_nolimits(struct aggr_beancounter *ab);
-struct beancounter init_bc;
+struct beancounter init_bc;
+struct aggr_beancounter init_ab;
unsigned int nr_beancounters = 1;
@@ -28,12 +34,64 @@ const char *bc_rnames[] = {
"privvmpages",
};
-#define BC_HASH_BITS 8
-#define BC_HASH_SIZE (1 << BC_HASH_BITS)
+/*
+ * Aggregated beancounters are stored in ab_hash bucket
+ */
+static struct hlist_head ab_hash[AB_HASH_SIZE];
+spinlock_t ab_hash_lock;
+
+struct aggr_beancounter *ab_findcreate(bcid_t id, int mask)
+{
+ struct aggr_beancounter *new_ab, *ab;
+ unsigned long flags;
+ struct hlist_head *slot;
+ struct hlist_node *pos;
+
+ /*
+ * Assumption: This function is called with a reference to ab held
+ */
+ slot = &ab_hash[ab_hash_fn(id)];
+ new_ab = NULL;
+
+retry:
+ spin_lock_irqsave(&ab_hash_lock, flags);
+ hlist_for_each_entry (ab, pos, slot, hash)
+ if (ab->ab_id == id)
+ break;
-static struct hlist_head bc_hash[BC_HASH_SIZE];
-static spinlock_t bc_hash_lock;
-#define bc_hash_fn(bcid) (hash_long(bcid, BC_HASH_BITS))
+ if (pos != NULL) {
+ get_aggr_beancounter(ab);
+ spin_unlock_irqrestore(&ab_hash_lock, flags);
+
+ if (new_ab != NULL)
+ kmem_cache_free(ab_cachep, new_ab);
+ return ab;
+ }
+
+ if (new_ab != NULL)
+ goto out_install;
+
+ spin_unlock_irqrestore(&ab_hash_lock, flags);
+
+ if (!(mask & BC_ALLOC))
+ goto out;
+
+ new_ab = kmem_cache_alloc(ab_cachep,
+ mask & BC_ALLOC_ATOMIC ? GFP_ATOMIC : GFP_KERNEL);
+ if (new_ab == NULL)
+ goto out;
+
+ init_aggr_beancounter_struct(new_ab, id);
+ init_aggr_beancounter_parm_nolimits(new_ab);
+ goto retry;
+
+out_install:
+ hlist_add_head(&new_ab->hash, slot);
+ nr_beancounters++;
+ spin_unlock_irqrestore(&ab_hash_lock, flags);
+out:
+ return new_ab;
+}
/*
* Per resource beancounting. Resources are tied to their bc id.
@@ -47,63 +105,159 @@ static spinlock_t bc_hash_lock;
* will mean the old entry is still around with resource tied to it.
*/
-struct beancounter *beancounter_findcreate(bcid_t id, int mask)
+struct beancounter *beancounter_find_locked(struct aggr_beancounter *ab,
+ bcid_t id)
{
- struct beancounter *new_bc, *bc;
- unsigned long flags;
+ struct beancounter *bc;
struct hlist_head *slot;
struct hlist_node *pos;
- slot = &bc_hash[bc_hash_fn(id)];
- new_bc = NULL;
+ /*
+ * Assumption: This function is called with a reference to ab held
+ */
+ slot = &ab->ab_bucket[bc_hash_fn(id)];
-retry:
- spin_lock_irqsave(&bc_hash_lock, flags);
hlist_for_each_entry (bc, pos, slot, hash)
if (bc->bc_id == id)
break;
if (pos != NULL) {
get_beancounter(bc);
- spin_unlock_irqrestore(&bc_hash_lock, flags);
+ return bc;
+ }
+ else
+ return NULL;
+}
+
+struct beancounter *beancounter_create(struct aggr_beancounter *ab, bcid_t id)
+{
+ unsigned long flags;
+ struct beancounter *bc = NULL, *new_bc;
+ struct hlist_head *slot;
+
+ get_aggr_beancounter(ab);
+ spin_lock_irqsave(&ab->ab_lock, flags);
+ bc = beancounter_find_locked(ab, id);
+ spin_unlock_irqrestore(&ab->ab_lock, flags);
- if (new_bc != NULL)
- kmem_cache_free(bc_cachep, new_bc);
+ if (bc)
return bc;
+ else {
+ new_bc = kmem_cache_alloc(bc_cachep, GFP_KERNEL);
+ *new_bc = default_beancounter;
+ init_beancounter_struct(ab, new_bc, id);
}
- if (new_bc != NULL)
- goto out_install;
+ spin_lock_irqsave(&ab->ab_lock, flags);
+ bc = beancounter_find_locked(ab, id);
+ if (unlikely(bc)) {
+ spin_unlock_irqrestore(&ab->ab_lock, flags);
+ kmem_cache_free(bc_cachep, new_bc);
+ return bc;
+ }
+ slot = &ab->ab_bucket[bc_hash_fn(id)];
+ hlist_add_head(&new_bc->hash, slot);
+ spin_unlock_irqrestore(&ab->ab_lock, flags);
+ return new_bc;
+}
- spin_unlock_irqrestore(&bc_hash_lock, flags);
+static void double_ab_lock(struct aggr_beancounter *ab1,
+ struct aggr_beancounter *ab2,
+ unsigned long *flags)
+{
+ if (ab1 > ab2) {
+ spin_lock_irqsave(&ab1->ab_lock, *flags);
+ spin_lock(&ab2->ab_lock);
+ } else if (ab2 > ab1) {
+ spin_lock_irqsave(&ab2->ab_lock, *flags);
+ spin_lock(&ab1->ab_lock);
+ } else
+ BUG();
+}
- if (!(mask & BC_ALLOC))
+static void double_ab_unlock(struct aggr_beancounter *ab1,
+ struct aggr_beancounter *ab2,
+ unsigned long *flags)
+{
+ if (ab1 > ab2) {
+ spin_unlock(&ab2->ab_lock);
+ spin_unlock_irqrestore(&ab1->ab_lock, *flags);
+ } else if (ab2 > ab1) {
+ spin_unlock(&ab1->ab_lock);
+ spin_unlock_irqrestore(&ab2->ab_lock, *flags);
+ } else
+ BUG();
+}
+
+/*
+ * This function should be called with a reference to dst_ab held
+ */
+struct beancounter *beancounter_relocate(struct aggr_beancounter *dst_ab,
+ struct aggr_beancounter *src_ab,
+ bcid_t id)
+{
+ unsigned long flags;
+ struct beancounter *bc = NULL, *new_bc;
+ struct hlist_head *slot;
+
+ double_ab_lock(dst_ab, src_ab, &flags);
+ bc = beancounter_find_locked(src_ab, id);
+ if (!bc)
goto out;
- new_bc = kmem_cache_alloc(bc_cachep,
- mask & BC_ALLOC_ATOMIC ? GFP_ATOMIC : GFP_KERNEL);
- if (new_bc == NULL)
+ /*
+ * Ideally this should be a BUG if new_bc is found.
+ * But we allow a small margin for several threads migrating
+ * to a new aggregated beancounter. BUG() it later.
+ */
+ new_bc = beancounter_find_locked(dst_ab, id);
+ if (new_bc) {
+ bc = new_bc;
goto out;
+ }
- *new_bc = default_beancounter;
- init_beancounter_struct(new_bc, id);
- goto retry;
+ spin_lock(&bc->bc_lock);
+ hlist_del(&bc->hash);
+ slot = &dst_ab->ab_bucket[bc_hash_fn(id)];
+ hlist_add_head(&bc->hash, slot);
+ bc->ab = dst_ab;
+ spin_unlock(&bc->bc_lock);
-out_install:
- hlist_add_head(&new_bc->hash, slot);
- nr_beancounters++;
- spin_unlock_irqrestore(&bc_hash_lock, flags);
out:
- return new_bc;
+ put_aggr_beancounter(src_ab);
+ double_ab_unlock(dst_ab, src_ab, &flags);
+ return bc;
+}
+
+void put_aggr_beancounter(struct aggr_beancounter *ab)
+{
+ int i;
+ unsigned long flags;
+
+ if (!atomic_dec_and_lock_irqsave(&ab->ab_refcount,
+ &ab_hash_lock, flags))
+ return;
+
+ for (i = 0; i < BC_RESOURCES; i++)
+ if (ab->ab_parms[i].held != 0)
+ printk("AB: %d has %lu of %s held on put", ab->ab_id,
+ ab->ab_parms[i].held, bc_rnames[i]);
+
+ hlist_del(&ab->hash);
+ nr_beancounters--;
+ spin_unlock_irqrestore(&ab_hash_lock, flags);
+
+ kmem_cache_free(ab_cachep, ab);
}
void put_beancounter(struct beancounter *bc)
{
int i;
unsigned long flags;
+ struct aggr_beancounter *ab = bc->ab;
if (!atomic_dec_and_lock_irqsave(&bc->bc_refcount,
- &bc_hash_lock, flags))
+ &ab->ab_lock, flags))
return;
BUG_ON(bc == &init_bc);
@@ -123,9 +277,10 @@ void put_beancounter(struct beancounter
#endif
hlist_del(&bc->hash);
nr_beancounters--;
- spin_unlock_irqrestore(&bc_hash_lock, flags);
+ spin_unlock_irqrestore(&ab->ab_lock, flags);
kmem_cache_free(bc_cachep, bc);
+ put_aggr_beancounter(ab);
}
EXPORT_SYMBOL_GPL(put_beancounter);
@@ -228,12 +383,38 @@ EXPORT_SYMBOL_GPL(bc_uncharge);
* of fields not initialized explicitly.
*/
-static void init_beancounter_struct(struct beancounter *bc, bcid_t id)
+static void init_beancounter_struct(struct aggr_beancounter *ab,
+ struct beancounter *bc, bcid_t id)
{
bc->bc_magic = BC_MAGIC;
atomic_set(&bc->bc_refcount, 1);
spin_lock_init(&bc->bc_lock);
bc->bc_id = id;
+ bc->ab = ab;
+}
+
+static void init_aggr_beancounter_struct(struct aggr_beancounter *ab,
+ bcid_t ab_id)
+{
+ int i;
+
+ spin_lock_init(&ab->ab_lock);
+ ab->ab_id = ab_id;
+ atomic_set(&ab->ab_refcount, 1);
+ for (i = 0; i < AB_HASH_SIZE; i++)
+ INIT_HLIST_HEAD(&ab->ab_bucket[i]);
+ INIT_HLIST_NODE(&ab->hash);
+}
+
+static void init_aggr_beancounter_parm_nolimits(struct aggr_beancounter *ab)
+{
+ int k;
+
+ for (k = 0; k < BC_RESOURCES; k++) {
+ ab->ab_parms[k].held = 0;
+ ab->ab_parms[k].limit = BC_MAXVALUE;
+ ab->ab_parms[k].barrier = BC_MAXVALUE;
+ }
}
static void init_beancounter_nolimits(struct beancounter *bc)
@@ -261,17 +442,24 @@ static void init_beancounter_syslimits(s
void __init bc_init_early(void)
{
struct beancounter *bc;
+ struct aggr_beancounter *ab;
struct hlist_head *slot;
bc = &init_bc;
+ ab = &init_ab;
init_beancounter_nolimits(bc);
- init_beancounter_struct(bc, 0);
+ init_aggr_beancounter_struct(ab, 0);
+ init_aggr_beancounter_parm_nolimits(ab);
+ init_beancounter_struct(ab, bc, 0);
- spin_lock_init(&bc_hash_lock);
- slot = &bc_hash[bc_hash_fn(bc->bc_id)];
+ slot = &ab->ab_bucket[bc_hash_fn(bc->bc_id)];
hlist_add_head(&bc->hash, slot);
+ spin_lock_init(&ab_hash_lock);
+ slot = &ab_hash[ab_hash_fn(ab->ab_id)];
+ hlist_add_head(&ab->hash, slot);
+
current->task_bc.exec_bc = get_beancounter(bc);
current->task_bc.fork_bc = get_beancounter(bc);
}
@@ -279,12 +467,18 @@ void __init bc_init_early(void)
void __init bc_init_late(void)
{
struct beancounter *bc;
+ struct aggr_beancounter *ab;
bc_cachep = kmem_cache_create("beancounters",
sizeof(struct beancounter), 0,
SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL, NULL);
+ ab_cachep = kmem_cache_create("aggr_beancounters",
+ sizeof(struct aggr_beancounter), 0,
+ SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL, NULL);
+
+ ab = &init_ab;
bc = &default_beancounter;
init_beancounter_syslimits(bc);
- init_beancounter_struct(bc, 0);
+ init_beancounter_struct(ab, bc, 0);
}
diff -puN kernel/bc/misc.c~add-aggr-bc kernel/bc/misc.c
--- linux-2.6.18-rc5/kernel/bc/misc.c~add-aggr-bc 2006-09-17 20:33:15.000000000 +0530
+++ linux-2.6.18-rc5-balbir/kernel/bc/misc.c 2006-09-17 20:33:15.000000000 +0530
@@ -16,7 +16,7 @@ void bc_task_charge(struct task_struct *
struct beancounter *bc;
new_bc = &new->task_bc;
- bc = beancounter_findcreate(new->tgid, BC_ALLOC);
+ bc = beancounter_create(parent->task_bc.exec_bc->ab, new->tgid);
if (!bc) {
printk(KERN_WARNING "failed to create bc %d for tgid %d\n",
bc->bc_id, new->tgid);
_
--
Balbir Singh,
Linux Technology Center,
IBM Software Labs
-
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