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if: avoid higher-order pages for hashing

This commit is contained in:
Thomas Schoebel-Theuer 2013-04-12 13:43:43 +02:00
parent e7c67b73b1
commit 3ca7f91900
2 changed files with 33 additions and 15 deletions
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40
kernel/mars_if.c
View File

@ -42,6 +42,14 @@
#include "mars_if.h"
#define IF_HASH_MAX (PAGE_SIZE / sizeof(struct if_hash_anchor))
#define IF_HASH_CHUNK (PAGE_SIZE * 32)
struct if_hash_anchor {
spinlock_t hash_lock;
struct list_head hash_anchor;
};
///////////////////////// own static definitions ////////////////////////
// TODO: check bounds, ensure that free minor numbers are recycled
@ -174,9 +182,9 @@ void _if_unplug(struct if_input *input)
list_del_init(&mref_a->plug_head);
hash_index = mref_a->hash_index;
traced_lock(&input->hash_lock[hash_index], flags);
traced_lock(&input->hash_table[hash_index].hash_lock, flags);
list_del_init(&mref_a->hash_head);
traced_unlock(&input->hash_lock[hash_index], flags);
traced_unlock(&input->hash_table[hash_index].hash_lock, flags);
mref = mref_a->object;
@ -393,8 +401,8 @@ if_make_request(struct request_queue *q, struct bio *bio)
hash_index = (pos / IF_HASH_CHUNK) % IF_HASH_MAX;
#ifdef REQUEST_MERGING
traced_lock(&input->hash_lock[hash_index], flags);
for (tmp = input->hash_table[hash_index].next; tmp != &input->hash_table[hash_index]; tmp = tmp->next) {
traced_lock(&input->hash_table[hash_index].hash_lock, flags);
for (tmp = input->hash_table[hash_index].hash_anchor.next; tmp != &input->hash_table[hash_index].hash_anchor; tmp = tmp->next) {
struct if_mref_aspect *tmp_a;
struct mref_object *tmp_mref;
int i;
@ -441,7 +449,7 @@ if_make_request(struct request_queue *q, struct bio *bio)
} // foreach hash collision list member
unlock:
traced_unlock(&input->hash_lock[hash_index], flags);
traced_unlock(&input->hash_table[hash_index].hash_lock, flags);
#endif
if (!mref) {
int prefetch_len;
@ -519,9 +527,9 @@ if_make_request(struct request_queue *q, struct bio *bio)
atomic_inc(&input->plugged_count);
mref_a->hash_index = hash_index;
traced_lock(&input->hash_lock[hash_index], flags);
list_add_tail(&mref_a->hash_head, &input->hash_table[hash_index]);
traced_unlock(&input->hash_lock[hash_index], flags);
traced_lock(&input->hash_table[hash_index].hash_lock, flags);
list_add_tail(&mref_a->hash_head, &input->hash_table[hash_index].hash_anchor);
traced_unlock(&input->hash_table[hash_index].hash_lock, flags);
traced_lock(&input->req_lock, flags);
list_add_tail(&mref_a->plug_head, &input->plug_anchor);
@ -992,9 +1000,15 @@ static int if_brick_destruct(struct if_brick *brick)
static int if_input_construct(struct if_input *input)
{
int i;
input->hash_table = brick_block_alloc(0, PAGE_SIZE);
if (unlikely(!input->hash_table)) {
MARS_ERR("cannot allocate hash table\n");
return -ENOMEM;
}
for (i = 0; i < IF_HASH_MAX; i++) {
spin_lock_init(&input->hash_lock[i]);
INIT_LIST_HEAD(&input->hash_table[i]);
spin_lock_init(&input->hash_table[i].hash_lock);
INIT_LIST_HEAD(&input->hash_table[i].hash_anchor);
}
INIT_LIST_HEAD(&input->plug_anchor);
sema_init(&input->kick_sem, 1);
@ -1012,6 +1026,12 @@ static int if_input_construct(struct if_input *input)
static int if_input_destruct(struct if_input *input)
{
int i;
for (i = 0; i < IF_HASH_MAX; i++) {
CHECK_HEAD_EMPTY(&input->hash_table[i].hash_anchor);
}
CHECK_HEAD_EMPTY(&input->plug_anchor);
brick_block_free(input->hash_table, PAGE_SIZE);
return 0;
}

8
kernel/mars_if.h
View File

@ -9,9 +9,6 @@
#define MAX_BIO 32
#define IF_HASH_MAX 2048
#define IF_HASH_CHUNK (PAGE_SIZE * 32)
//#define USE_TIMER (HZ/10) // use this ONLY for debugging
/* I don't want to enhance / intrude into struct bio for compatibility reasons
@ -37,6 +34,8 @@ struct if_mref_aspect {
struct if_input *input;
};
struct if_hash_anchor;
struct if_input {
MARS_INPUT(if);
// TODO: move this to if_brick (better systematics)
@ -64,8 +63,7 @@ struct if_input {
atomic_t total_mref_write_count;
spinlock_t req_lock;
struct semaphore kick_sem;
spinlock_t hash_lock[IF_HASH_MAX];
struct list_head hash_table[IF_HASH_MAX];
struct if_hash_anchor *hash_table;
};
struct if_output {