mirror of https://github.com/schoebel/mars
375 lines
8.7 KiB
C
375 lines
8.7 KiB
C
// (c) 2012 Thomas Schoebel-Theuer / 1&1 Internet AG
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#include "lib_mapfree.h"
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/string.h>
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#include <linux/list.h>
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#include <linux/types.h>
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#include <linux/blkdev.h>
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#include <linux/spinlock.h>
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#include <linux/wait.h>
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#include <linux/file.h>
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// time to wait between background mapfree operations
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int mapfree_period_sec = 10;
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EXPORT_SYMBOL_GPL(mapfree_period_sec);
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// some grace space where no regular cleanup should occur
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int mapfree_grace_keep_mb = 16;
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EXPORT_SYMBOL_GPL(mapfree_grace_keep_mb);
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static
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DECLARE_RWSEM(mapfree_mutex);
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static
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LIST_HEAD(mapfree_list);
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static
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void mapfree_pages(struct mapfree_info *mf, int grace_keep)
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{
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struct address_space *mapping;
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pgoff_t start;
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pgoff_t end;
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if (unlikely(!mf->mf_filp || !(mapping = mf->mf_filp->f_mapping)))
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goto done;
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if (grace_keep < 0) { // force full flush
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start = 0;
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end = -1;
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} else {
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unsigned long flags;
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loff_t tmp;
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loff_t min;
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traced_lock(&mf->mf_lock, flags);
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min = tmp = mf->mf_min[0];
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if (likely(mf->mf_min[1] < min))
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min = mf->mf_min[1];
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if (tmp) {
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mf->mf_min[1] = tmp;
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mf->mf_min[0] = 0;
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}
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traced_unlock(&mf->mf_lock, flags);
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min -= (loff_t)grace_keep * (1024 * 1024); // megabytes
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end = 0;
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if (min > 0 || mf->mf_last) {
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start = mf->mf_last / PAGE_SIZE;
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// add some grace overlapping
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if (likely(start > 0))
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start--;
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mf->mf_last = min;
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end = min / PAGE_SIZE;
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} else { // there was no progress for at least 2 rounds
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start = 0;
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if (!grace_keep) // also flush thoroughly
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end = -1;
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}
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MARS_DBG("file = '%s' start = %lu end = %lu\n", SAFE_STR(mf->mf_name), start, end);
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}
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if (end > start || end == -1) {
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invalidate_mapping_pages(mapping, start, end);
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}
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done:;
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}
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static
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void _mapfree_put(struct mapfree_info *mf)
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{
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if (atomic_dec_and_test(&mf->mf_count)) {
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MARS_DBG("closing file '%s' filp = %p\n", mf->mf_name, mf->mf_filp);
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list_del_init(&mf->mf_head);
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CHECK_HEAD_EMPTY(&mf->mf_dirty_anchor);
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if (likely(mf->mf_filp)) {
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mapfree_pages(mf, -1);
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filp_close(mf->mf_filp, NULL);
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}
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brick_string_free(mf->mf_name);
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brick_mem_free(mf);
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}
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}
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void mapfree_put(struct mapfree_info *mf)
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{
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down_write(&mapfree_mutex);
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_mapfree_put(mf);
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up_write(&mapfree_mutex);
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}
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EXPORT_SYMBOL_GPL(mapfree_put);
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struct mapfree_info *mapfree_get(const char *name, int flags)
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{
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struct mapfree_info *mf = NULL;
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struct list_head *tmp;
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if (!(flags & O_DIRECT)) {
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down_read(&mapfree_mutex);
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for (tmp = mapfree_list.next; tmp != &mapfree_list; tmp = tmp->next) {
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struct mapfree_info *_mf = container_of(tmp, struct mapfree_info, mf_head);
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if (_mf->mf_flags == flags && !strcmp(_mf->mf_name, name)) {
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mf = _mf;
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atomic_inc(&mf->mf_count);
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break;
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}
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}
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up_read(&mapfree_mutex);
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if (mf)
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goto done;
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}
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for (;;) {
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struct address_space *mapping;
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struct inode *inode;
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int ra = 1;
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int prot = 0600;
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mm_segment_t oldfs;
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mf = brick_zmem_alloc(sizeof(struct mapfree_info));
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if (unlikely(!mf)) {
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MARS_ERR("no mem, name = '%s'\n", name);
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continue;
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}
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mf->mf_name = brick_strdup(name);
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if (unlikely(!mf->mf_name)) {
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MARS_ERR("no mem, name = '%s'\n", name);
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brick_mem_free(mf);
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continue;
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}
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mf->mf_flags = flags;
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INIT_LIST_HEAD(&mf->mf_head);
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INIT_LIST_HEAD(&mf->mf_dirty_anchor);
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atomic_set(&mf->mf_count, 1);
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spin_lock_init(&mf->mf_lock);
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mf->mf_max = -1;
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oldfs = get_fs();
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set_fs(get_ds());
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mf->mf_filp = filp_open(name, flags, prot);
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set_fs(oldfs);
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MARS_DBG("file '%s' flags = %d prot = %d filp = %p\n", name, flags, prot, mf->mf_filp);
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if (unlikely(!mf->mf_filp || IS_ERR(mf->mf_filp))) {
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int err = PTR_ERR(mf->mf_filp);
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MARS_ERR("can't open file '%s' status=%d\n", name, err);
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mf->mf_filp = NULL;
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_mapfree_put(mf);
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mf = NULL;
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break;
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}
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if (unlikely(!(mapping = mf->mf_filp->f_mapping) ||
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!(inode = mapping->host))) {
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MARS_ERR("file '%s' has no mapping\n", name);
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mf->mf_filp = NULL;
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_mapfree_put(mf);
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mf = NULL;
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break;
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}
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mapping_set_gfp_mask(mapping, mapping_gfp_mask(mapping) & ~(__GFP_IO | __GFP_FS));
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mf->mf_max = i_size_read(inode);
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if (S_ISBLK(inode->i_mode)) {
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MARS_INF("changing blkdev readahead from %lu to %d\n", inode->i_bdev->bd_disk->queue->backing_dev_info.ra_pages, ra);
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inode->i_bdev->bd_disk->queue->backing_dev_info.ra_pages = ra;
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}
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if (flags & O_DIRECT) { // never share them
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break;
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}
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// maintain global list of all open files
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down_write(&mapfree_mutex);
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for (tmp = mapfree_list.next; tmp != &mapfree_list; tmp = tmp->next) {
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struct mapfree_info *_mf = container_of(tmp, struct mapfree_info, mf_head);
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if (unlikely(_mf->mf_flags == flags && !strcmp(_mf->mf_name, name))) {
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MARS_WRN("race on creation of '%s' detected\n", name);
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_mapfree_put(mf);
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mf = _mf;
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atomic_inc(&mf->mf_count);
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goto leave;
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}
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}
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list_add_tail(&mf->mf_head, &mapfree_list);
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leave:
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up_write(&mapfree_mutex);
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break;
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}
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done:
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return mf;
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}
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EXPORT_SYMBOL_GPL(mapfree_get);
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void mapfree_set(struct mapfree_info *mf, loff_t min, loff_t max)
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{
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unsigned long flags;
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traced_lock(&mf->mf_lock, flags);
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if (!mf->mf_min[0] || mf->mf_min[0] > min)
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mf->mf_min[0] = min;
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if (max >= 0 && mf->mf_max < max)
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mf->mf_max = max;
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traced_unlock(&mf->mf_lock, flags);
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}
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EXPORT_SYMBOL_GPL(mapfree_set);
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static
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int mapfree_thread(void *data)
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{
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while (!brick_thread_should_stop()) {
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struct mapfree_info *mf = NULL;
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struct list_head *tmp;
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long long eldest = 0;
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brick_msleep(500);
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if (mapfree_period_sec <= 0)
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continue;
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down_read(&mapfree_mutex);
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for (tmp = mapfree_list.next; tmp != &mapfree_list; tmp = tmp->next) {
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struct mapfree_info *_mf = container_of(tmp, struct mapfree_info, mf_head);
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if (unlikely(!_mf->mf_jiffies)) {
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_mf->mf_jiffies = jiffies;
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continue;
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}
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if ((long long)jiffies - _mf->mf_jiffies > mapfree_period_sec * HZ &&
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(!mf || _mf->mf_jiffies < eldest)) {
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mf = _mf;
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eldest = _mf->mf_jiffies;
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}
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}
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if (mf)
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atomic_inc(&mf->mf_count);
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up_read(&mapfree_mutex);
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if (!mf) {
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continue;
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}
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mapfree_pages(mf, mapfree_grace_keep_mb);
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mf->mf_jiffies = jiffies;
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mapfree_put(mf);
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}
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return 0;
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}
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////////////////// dirty IOs on the fly //////////////////
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void mf_insert_dirty(struct mapfree_info *mf, struct dirty_info *di)
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{
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if (likely(di->dirty_mref)) {
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unsigned long flags = 0;
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traced_lock(&mf->mf_lock, flags);
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list_del(&di->dirty_head);
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list_add(&di->dirty_head, &mf->mf_dirty_anchor);
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traced_unlock(&mf->mf_lock, flags);
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}
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}
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EXPORT_SYMBOL_GPL(mf_insert_dirty);
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void mf_remove_dirty(struct mapfree_info *mf, struct dirty_info *di)
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{
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if (!list_empty(&di->dirty_head)) {
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unsigned long flags = 0;
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traced_lock(&mf->mf_lock, flags);
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list_del_init(&di->dirty_head);
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traced_unlock(&mf->mf_lock, flags);
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}
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}
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EXPORT_SYMBOL_GPL(mf_remove_dirty);
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void mf_get_dirty(struct mapfree_info *mf, loff_t *min, loff_t *max, int min_stage, int max_stage)
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{
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struct list_head *tmp;
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unsigned long flags = 0;
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traced_lock(&mf->mf_lock, flags);
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for (tmp = mf->mf_dirty_anchor.next; tmp != &mf->mf_dirty_anchor; tmp = tmp->next) {
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struct dirty_info *di = container_of(tmp, struct dirty_info, dirty_head);
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struct mref_object *mref = di->dirty_mref;
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if (unlikely(!mref)) {
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continue;
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}
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if (di->dirty_stage < min_stage || di->dirty_stage > max_stage) {
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continue;
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}
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if (mref->ref_pos < *min) {
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*min = mref->ref_pos;
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}
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if (mref->ref_pos + mref->ref_len > *max) {
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*max = mref->ref_pos + mref->ref_len;
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}
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}
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traced_unlock(&mf->mf_lock, flags);
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}
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EXPORT_SYMBOL_GPL(mf_get_dirty);
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void mf_get_any_dirty(const char *filename, loff_t *min, loff_t *max, int min_stage, int max_stage)
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{
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struct list_head *tmp;
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down_read(&mapfree_mutex);
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for (tmp = mapfree_list.next; tmp != &mapfree_list; tmp = tmp->next) {
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struct mapfree_info *mf = container_of(tmp, struct mapfree_info, mf_head);
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if (!strcmp(mf->mf_name, filename)) {
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mf_get_dirty(mf, min, max, min_stage, max_stage);
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}
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}
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up_read(&mapfree_mutex);
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}
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EXPORT_SYMBOL_GPL(mf_get_any_dirty);
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////////////////// module init stuff /////////////////////////
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static
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struct task_struct *mf_thread = NULL;
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int __init init_mars_mapfree(void)
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{
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MARS_DBG("init_mapfree()\n");
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mf_thread = brick_thread_create(mapfree_thread, NULL, "mars_mapfree");
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if (unlikely(!mf_thread)) {
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MARS_ERR("could not create mapfree thread\n");
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return -ENOMEM;
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}
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return 0;
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}
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void exit_mars_mapfree(void)
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{
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MARS_DBG("exit_mapfree()\n");
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if (likely(mf_thread)) {
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brick_thread_stop(mf_thread);
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mf_thread = NULL;
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}
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}
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#ifndef CONFIG_MARS_HAVE_BIGMODULE
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MODULE_DESCRIPTION("MARS mapfree infrastructure");
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MODULE_AUTHOR("Thomas Schoebel-Theuer <tst@1und1.de>");
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MODULE_LICENSE("GPL");
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module_init(init_mars_mapfree);
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module_exit(exit_mars_mapfree);
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#endif
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