[PATCH 24/50] mars: add new file drivers/block/mars/xio_bricks/lib_mapfree.c

Thomas Schoebel-Theuer
2014-07-01T22:02:32Z

drivers/block/mars/xio_bricks/lib_mapfree.c | 356 ++++++++++++++++++++++++++++
1 file changed, 356 insertions(+)
create mode 100644 drivers/block/mars/xio_bricks/lib_mapfree.c

diff --git a/drivers/block/mars/xio_bricks/lib_mapfree.c b/drivers/block/mars/xio_bricks/lib_mapfree.c
new file mode 100644
index 0000000..99a5ce9
--- /dev/null
+++ b/drivers/block/mars/xio_bricks/lib_mapfree.c
@@ -0,0 +1,356 @@
+/* (c) 2012 Thomas Schoebel-Theuer / 1&1 Internet AG */
+
+#include <linux/lib_mapfree.h>
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/list.h>
+#include <linux/types.h>
+#include <linux/blkdev.h>
+#include <linux/spinlock.h>
+#include <linux/wait.h>
+#include <linux/file.h>
+
+/* time to wait between background mapfree operations */
+int mapfree_period_sec = 10;
+EXPORT_SYMBOL_GPL(mapfree_period_sec);
+
+/* some grace space where no regular cleanup should occur */
+int mapfree_grace_keep_mb = 16;
+EXPORT_SYMBOL_GPL(mapfree_grace_keep_mb);
+
+static
+DECLARE_RWSEM(mapfree_mutex);
+
+static
+LIST_HEAD(mapfree_list);
+
+static
+void mapfree_pages(struct mapfree_info *mf, int grace_keep)
+{
+ struct address_space *mapping;
+ pgoff_t start;
+ pgoff_t end;
+
+ if (unlikely(!mf->mf_filp))
+ goto done;
+
+ mapping = mf->mf_filp->f_mapping;
+ if (unlikely(!mapping))
+ goto done;
+
+ if (grace_keep < 0) { /* force full flush */
+ start = 0;
+ end = -1;
+ } else {
+ loff_t tmp;
+ loff_t min;
+
+ spin_lock(&mf->mf_lock);
+
+ min = tmp = mf->mf_min[0];
+ if (likely(mf->mf_min[1] < min))
+ min = mf->mf_min[1];
+ if (tmp) {
+ mf->mf_min[1] = tmp;
+ mf->mf_min[0] = 0;
+ }
+
+ spin_unlock(&mf->mf_lock);
+
+ min -= (loff_t)grace_keep * (1024 * 1024); /* megabytes */
+ end = 0;
+
+ if (min > 0 || mf->mf_last) {
+ start = mf->mf_last / PAGE_SIZE;
+ /* add some grace overlapping */
+ if (likely(start > 0))
+ start--;
+ mf->mf_last = min;
+ end = min / PAGE_SIZE;
+ } else { /* there was no progress for at least 2 rounds */
+ start = 0;
+ if (!grace_keep) /* also flush thoroughly */
+ end = -1;
+ }
+
+ XIO_DBG("file = '%s' start = %lu end = %lu\n", SAFE_STR(mf->mf_name), start, end);
+ }
+
+ if (end > start || end == -1)
+ invalidate_mapping_pages(mapping, start, end);
+
+done:;
+}
+
+static
+void _mapfree_put(struct mapfree_info *mf)
+{
+ if (atomic_dec_and_test(&mf->mf_count)) {
+ XIO_DBG("closing file '%s' filp = %p\n", mf->mf_name, mf->mf_filp);
+ list_del_init(&mf->mf_head);
+ CHECK_HEAD_EMPTY(&mf->mf_dirty_anchor);
+ if (likely(mf->mf_filp)) {
+ mapfree_pages(mf, -1);
+ filp_close(mf->mf_filp, NULL);
+ }
+ brick_string_free(mf->mf_name);
+ brick_mem_free(mf);
+ }
+}
+
+void mapfree_put(struct mapfree_info *mf)
+{
+ down_write(&mapfree_mutex);
+ _mapfree_put(mf);
+ up_write(&mapfree_mutex);
+}
+EXPORT_SYMBOL_GPL(mapfree_put);
+
+struct mapfree_info *mapfree_get(const char *name, int flags)
+{
+ struct mapfree_info *mf = NULL;
+ struct list_head *tmp;
+
+ if (!(flags & O_DIRECT)) {
+ down_read(&mapfree_mutex);
+ for (tmp = mapfree_list.next; tmp != &mapfree_list; tmp = tmp->next) {
+ struct mapfree_info *_mf = container_of(tmp, struct mapfree_info, mf_head);
+
+ if (_mf->mf_flags == flags && !strcmp(_mf->mf_name, name)) {
+ mf = _mf;
+ atomic_inc(&mf->mf_count);
+ break;
+ }
+ }
+ up_read(&mapfree_mutex);
+
+ if (mf)
+ goto done;
+ }
+
+ for (;;) {
+ struct address_space *mapping;
+ struct inode *inode = NULL;
+ int ra = 1;
+ int prot = 0600;
+
+ mm_segment_t oldfs;
+
+ mf = brick_zmem_alloc(sizeof(struct mapfree_info));
+
+ mf->mf_name = brick_strdup(name);
+
+ mf->mf_flags = flags;
+ INIT_LIST_HEAD(&mf->mf_head);
+ INIT_LIST_HEAD(&mf->mf_dirty_anchor);
+ atomic_set(&mf->mf_count, 1);
+ spin_lock_init(&mf->mf_lock);
+ mf->mf_max = -1;
+
+ oldfs = get_fs();
+ set_fs(get_ds());
+ mf->mf_filp = filp_open(name, flags, prot);
+ set_fs(oldfs);
+
+ XIO_DBG("file '%s' flags = %d prot = %d filp = %p\n", name, flags, prot, mf->mf_filp);
+
+ if (unlikely(!mf->mf_filp || IS_ERR(mf->mf_filp))) {
+ int err = PTR_ERR(mf->mf_filp);
+
+ XIO_ERR("can't open file '%s' status=%d\n", name, err);
+ mf->mf_filp = NULL;
+ _mapfree_put(mf);
+ mf = NULL;
+ break;
+ }
+
+ mapping = mf->mf_filp->f_mapping;
+ if (likely(mapping))
+ inode = mapping->host;
+ if (unlikely(!mapping || !inode)) {
+ XIO_ERR("file '%s' has no mapping\n", name);
+ mf->mf_filp = NULL;
+ _mapfree_put(mf);
+ mf = NULL;
+ break;
+ }
+
+ mapping_set_gfp_mask(mapping, mapping_gfp_mask(mapping) & ~(__GFP_IO | __GFP_FS));
+
+ mf->mf_max = i_size_read(inode);
+
+ if (S_ISBLK(inode->i_mode)) {
+ XIO_INF("changing blkdev readahead from %lu to %d\n",
+ inode->i_bdev->bd_disk->queue->backing_dev_info.ra_pages,
+ ra);
+ inode->i_bdev->bd_disk->queue->backing_dev_info.ra_pages = ra;
+ }
+
+ if (flags & O_DIRECT) { /* never share them */
+ break;
+ }
+
+ /* maintain global list of all open files */
+ down_write(&mapfree_mutex);
+ for (tmp = mapfree_list.next; tmp != &mapfree_list; tmp = tmp->next) {
+ struct mapfree_info *_mf = container_of(tmp, struct mapfree_info, mf_head);
+
+ if (unlikely(_mf->mf_flags == flags && !strcmp(_mf->mf_name, name))) {
+ XIO_WRN("race on creation of '%s' detected\n", name);
+ _mapfree_put(mf);
+ mf = _mf;
+ atomic_inc(&mf->mf_count);
+ goto leave;
+ }
+ }
+ list_add_tail(&mf->mf_head, &mapfree_list);
+leave:
+ up_write(&mapfree_mutex);
+ break;
+ }
+done:
+ return mf;
+}
+EXPORT_SYMBOL_GPL(mapfree_get);
+
+void mapfree_set(struct mapfree_info *mf, loff_t min, loff_t max)
+{
+ spin_lock(&mf->mf_lock);
+ if (!mf->mf_min[0] || mf->mf_min[0] > min)
+ mf->mf_min[0] = min;
+ if (max >= 0 && mf->mf_max < max)
+ mf->mf_max = max;
+ spin_unlock(&mf->mf_lock);
+}
+EXPORT_SYMBOL_GPL(mapfree_set);
+
+static
+int mapfree_thread(void *data)
+{
+ while (!brick_thread_should_stop()) {
+ struct mapfree_info *mf = NULL;
+ struct list_head *tmp;
+ long long eldest = 0;
+
+ brick_msleep(500);
+
+ if (mapfree_period_sec <= 0)
+ continue;
+
+ down_read(&mapfree_mutex);
+
+ for (tmp = mapfree_list.next; tmp != &mapfree_list; tmp = tmp->next) {
+ struct mapfree_info *_mf = container_of(tmp, struct mapfree_info, mf_head);
+
+ if (unlikely(!_mf->mf_jiffies)) {
+ _mf->mf_jiffies = jiffies;
+ continue;
+ }
+ if ((long long)jiffies - _mf->mf_jiffies > mapfree_period_sec * HZ &&
+ (!mf || _mf->mf_jiffies < eldest)) {
+ mf = _mf;
+ eldest = _mf->mf_jiffies;
+ }
+ }
+ if (mf)
+ atomic_inc(&mf->mf_count);
+
+ up_read(&mapfree_mutex);
+
+ if (!mf)
+ continue;
+
+ mapfree_pages(mf, mapfree_grace_keep_mb);
+
+ mf->mf_jiffies = jiffies;
+ mapfree_put(mf);
+ }
+ return 0;
+}
+
+/***************** dirty IOs on the fly *****************/
+
+void mf_insert_dirty(struct mapfree_info *mf, struct dirty_info *di)
+{
+ if (likely(di->dirty_aio)) {
+ spin_lock(&mf->mf_lock);
+ list_del(&di->dirty_head);
+ list_add(&di->dirty_head, &mf->mf_dirty_anchor);
+ spin_unlock(&mf->mf_lock);
+ }
+}
+EXPORT_SYMBOL_GPL(mf_insert_dirty);
+
+void mf_remove_dirty(struct mapfree_info *mf, struct dirty_info *di)
+{
+ if (!list_empty(&di->dirty_head)) {
+ spin_lock(&mf->mf_lock);
+ list_del_init(&di->dirty_head);
+ spin_unlock(&mf->mf_lock);
+ }
+}
+EXPORT_SYMBOL_GPL(mf_remove_dirty);
+
+void mf_get_dirty(struct mapfree_info *mf, loff_t *min, loff_t *max, int min_stage, int max_stage)
+{
+ struct list_head *tmp;
+
+ spin_lock(&mf->mf_lock);
+ for (tmp = mf->mf_dirty_anchor.next; tmp != &mf->mf_dirty_anchor; tmp = tmp->next) {
+ struct dirty_info *di = container_of(tmp, struct dirty_info, dirty_head);
+ struct aio_object *aio = di->dirty_aio;
+
+ if (unlikely(!aio))
+ continue;
+ if (di->dirty_stage < min_stage || di->dirty_stage > max_stage)
+ continue;
+ if (aio->io_pos < *min)
+ *min = aio->io_pos;
+ if (aio->io_pos + aio->io_len > *max)
+ *max = aio->io_pos + aio->io_len;
+ }
+ spin_unlock(&mf->mf_lock);
+}
+EXPORT_SYMBOL_GPL(mf_get_dirty);
+
+void mf_get_any_dirty(const char *filename, loff_t *min, loff_t *max, int min_stage, int max_stage)
+{
+ struct list_head *tmp;
+
+ down_read(&mapfree_mutex);
+ for (tmp = mapfree_list.next; tmp != &mapfree_list; tmp = tmp->next) {
+ struct mapfree_info *mf = container_of(tmp, struct mapfree_info, mf_head);
+
+ if (!strcmp(mf->mf_name, filename))
+ mf_get_dirty(mf, min, max, min_stage, max_stage);
+ }
+ up_read(&mapfree_mutex);
+}
+EXPORT_SYMBOL_GPL(mf_get_any_dirty);
+
+/***************** module init stuff ************************/
+
+static
+struct task_struct *mf_thread = NULL;
+
+int __init init_xio_mapfree(void)
+{
+ XIO_DBG("init_mapfree()\n");
+ mf_thread = brick_thread_create(mapfree_thread, NULL, "xio_mapfree");
+ if (unlikely(!mf_thread)) {
+ XIO_ERR("could not create mapfree thread\n");
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+void exit_xio_mapfree(void)
+{
+ XIO_DBG("exit_mapfree()\n");
+ if (likely(mf_thread)) {
+ brick_thread_stop(mf_thread);
+ mf_thread = NULL;
+ }
+}
--
2.0.0