From: Jens Axboe <jens.axboe@oracle.com>
Date: Sat, 1 Mar 2008 17:56:24 +0000 (+0100)
Subject: Add file hashing helpers
X-Git-Tag: fio-1.20-rc1~13
X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=380065aa652b87093d6bbd240e70db30bd6f193d;hp=2e5cdb118aeb26cb469a50f746b632676306f698;ds=sidebyside

Add file hashing helpers

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---

diff --git a/Makefile b/Makefile
index 7c79e910..1380c02c 100644
--- a/Makefile
+++ b/Makefile
@@ -7,7 +7,7 @@ PROGS	= fio
 SCRIPTS = fio_generate_plots
 OBJS = gettime.o fio.o ioengines.o init.o stat.o log.o time.o filesetup.o \
 	eta.o verify.o memory.o io_u.o parse.o mutex.o sem.o options.o \
-	rbtree.o diskutil.o fifo.o blktrace.o smalloc.o
+	rbtree.o diskutil.o fifo.o blktrace.o smalloc.o filehash.o
 
 OBJS += crc/crc7.o
 OBJS += crc/crc16.o
diff --git a/filehash.c b/filehash.c
new file mode 100644
index 00000000..1bcfc6de
--- /dev/null
+++ b/filehash.c
@@ -0,0 +1,107 @@
+#include <stdlib.h>
+#include <assert.h>
+
+#include "fio.h"
+#include "list.h"
+#include "crc/crc16.h"
+
+#define HASH_BUCKETS	512
+#define HASH_MASK	(HASH_BUCKETS - 1)
+
+unsigned int file_hash_size = HASH_BUCKETS * sizeof(struct list_head);
+
+static struct list_head *file_hash;
+static struct fio_mutex *hash_lock;
+
+static void dump_hash(void)
+{
+	struct list_head *n;
+	unsigned int i;
+
+	for (i = 0; i < HASH_BUCKETS; i++) {
+		list_for_each(n, &file_hash[i]) {
+			struct fio_file *f;
+
+			f = list_entry(n, struct fio_file, hash_list);
+			printf("%d: %s\n", i, f->file_name);
+		}
+	}
+}
+
+static unsigned short hash(const char *name)
+{
+	return crc16((const unsigned char *) name, strlen(name)) & HASH_MASK;
+}
+
+void remove_file_hash(struct fio_file *f)
+{
+	fio_mutex_down(hash_lock);
+
+	if (f->flags & FIO_FILE_HASHED) {
+		assert(!list_empty(&f->hash_list));
+		list_del_init(&f->hash_list);
+		f->flags &= ~FIO_FILE_HASHED;
+	}
+
+	fio_mutex_up(hash_lock);
+}
+
+static struct fio_file *__lookup_file_hash(const char *name)
+{
+	struct list_head *bucket = &file_hash[hash(name)];
+	struct list_head *n;
+
+	list_for_each(n, bucket) {
+		struct fio_file *f = list_entry(n, struct fio_file, hash_list);
+
+		if (!strcmp(f->file_name, name)) {
+			assert(f->fd != -1);
+			return f;
+		}
+	}
+
+	dump_hash();
+	return NULL;
+}
+
+struct fio_file *lookup_file_hash(const char *name)
+{
+	struct fio_file *f;
+
+	fio_mutex_down(hash_lock);
+	f = __lookup_file_hash(name);
+	fio_mutex_up(hash_lock);
+	return f;
+}
+
+struct fio_file *add_file_hash(struct fio_file *f)
+{
+	struct fio_file *alias;
+
+	if (f->flags & FIO_FILE_HASHED)
+		return NULL;
+
+	INIT_LIST_HEAD(&f->hash_list);
+
+	fio_mutex_down(hash_lock);
+
+	alias = __lookup_file_hash(f->file_name);
+	if (!alias) {
+		f->flags |= FIO_FILE_HASHED;
+		list_add_tail(&f->hash_list, &file_hash[hash(f->file_name)]);
+	}
+
+	fio_mutex_up(hash_lock);
+	return alias;
+}
+
+void file_hash_init(void *ptr)
+{
+	unsigned int i;
+
+	file_hash = ptr;
+	for (i = 0; i < HASH_BUCKETS; i++)
+		INIT_LIST_HEAD(&file_hash[i]);
+
+	hash_lock = fio_mutex_init(1);
+}
diff --git a/filehash.h b/filehash.h
new file mode 100644
index 00000000..a89a91f8
--- /dev/null
+++ b/filehash.h
@@ -0,0 +1,11 @@
+#ifndef FIO_FILE_HASH_H
+#define FIO_FILE_HASH_H
+
+extern unsigned int file_hash_size;
+
+extern void file_hash_init(void *);
+extern struct fio_file *lookup_file_hash(const char *);
+extern struct fio_file *add_file_hash(struct fio_file *);
+extern void remove_file_hash(struct fio_file *);
+
+#endif
diff --git a/init.c b/init.c
index e53f103f..4d336fa3 100644
--- a/init.c
+++ b/init.c
@@ -17,6 +17,7 @@
 #include "fio.h"
 #include "parse.h"
 #include "smalloc.h"
+#include "filehash.h"
 
 static char fio_version_string[] = "fio 1.19";
 
@@ -750,10 +751,13 @@ static void free_shm(void)
 /*
  * The thread area is shared between the main process and the job
  * threads/processes. So setup a shared memory segment that will hold
- * all the job info.
+ * all the job info. We use the end of the region for keeping track of
+ * open files across jobs, for file sharing.
  */
 static int setup_thread_area(void)
 {
+	void *hash;
+
 	/*
 	 * 1024 is too much on some machines, scale max_jobs if
 	 * we get a failure that looks like too large a shm segment
@@ -761,6 +765,8 @@ static int setup_thread_area(void)
 	do {
 		size_t size = max_jobs * sizeof(struct thread_data);
 
+		size += file_hash_size;
+
 		shm_id = shmget(0, size, IPC_CREAT | 0600);
 		if (shm_id != -1)
 			break;
@@ -782,6 +788,8 @@ static int setup_thread_area(void)
 	}
 
 	memset(threads, 0, max_jobs * sizeof(struct thread_data));
+	hash = (void *) threads + max_jobs * sizeof(struct thread_data);
+	file_hash_init(hash);
 	atexit(free_shm);
 	return 0;
 }