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authorNeilBrown <neilb@suse.de>2006-06-26 03:27:44 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-26 12:58:38 -0400
commit0b79ccf0cdd9f59e5f99017e1a5d23da336544b2 (patch)
tree8688d9810fcba1e24abce726eaf35ff32f6b58d9
parentd7375ab324971e7acbea9f02a0269ae7348f4147 (diff)
[PATCH] md/bitmap: remove bitmap writeback daemon
md/bitmap currently has a separate thread to wait for writes to the bitmap file to complete (as we cannot get a callback on that action). However this isn't needed as bitmap_unplug is called from process context and waits for the writeback thread to do it's work. The same result can be achieved by doing the waiting directly in bitmap_unplug. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--drivers/md/bitmap.c115
-rw-r--r--include/linux/raid/bitmap.h6
2 files changed, 8 insertions, 113 deletions
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index f8ffaee20ff8..814f412a410c 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -7,7 +7,6 @@
7 * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.: 7 * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
8 * - added disk storage for bitmap 8 * - added disk storage for bitmap
9 * - changes to allow various bitmap chunk sizes 9 * - changes to allow various bitmap chunk sizes
10 * - added bitmap daemon (to asynchronously clear bitmap bits from disk)
11 */ 10 */
12 11
13/* 12/*
@@ -330,14 +329,13 @@ static int write_page(struct bitmap *bitmap, struct page *page, int wait)
330 set_page_dirty(page); /* force it to be written out */ 329 set_page_dirty(page); /* force it to be written out */
331 330
332 if (!wait) { 331 if (!wait) {
333 /* add to list to be waited for by daemon */ 332 /* add to list to be waited for */
334 struct page_list *item = mempool_alloc(bitmap->write_pool, GFP_NOIO); 333 struct page_list *item = mempool_alloc(bitmap->write_pool, GFP_NOIO);
335 item->page = page; 334 item->page = page;
336 get_page(page); 335 get_page(page);
337 spin_lock(&bitmap->write_lock); 336 spin_lock(&bitmap->write_lock);
338 list_add(&item->list, &bitmap->complete_pages); 337 list_add(&item->list, &bitmap->complete_pages);
339 spin_unlock(&bitmap->write_lock); 338 spin_unlock(&bitmap->write_lock);
340 md_wakeup_thread(bitmap->writeback_daemon);
341 } 339 }
342 return write_one_page(page, wait); 340 return write_one_page(page, wait);
343} 341}
@@ -621,8 +619,6 @@ static void bitmap_file_unmap(struct bitmap *bitmap)
621 safe_put_page(sb_page); 619 safe_put_page(sb_page);
622} 620}
623 621
624static void bitmap_stop_daemon(struct bitmap *bitmap);
625
626/* dequeue the next item in a page list -- don't call from irq context */ 622/* dequeue the next item in a page list -- don't call from irq context */
627static struct page_list *dequeue_page(struct bitmap *bitmap) 623static struct page_list *dequeue_page(struct bitmap *bitmap)
628{ 624{
@@ -648,8 +644,6 @@ static void drain_write_queues(struct bitmap *bitmap)
648 put_page(item->page); 644 put_page(item->page);
649 mempool_free(item, bitmap->write_pool); 645 mempool_free(item, bitmap->write_pool);
650 } 646 }
651
652 wake_up(&bitmap->write_wait);
653} 647}
654 648
655static void bitmap_file_put(struct bitmap *bitmap) 649static void bitmap_file_put(struct bitmap *bitmap)
@@ -663,8 +657,6 @@ static void bitmap_file_put(struct bitmap *bitmap)
663 bitmap->file = NULL; 657 bitmap->file = NULL;
664 spin_unlock_irqrestore(&bitmap->lock, flags); 658 spin_unlock_irqrestore(&bitmap->lock, flags);
665 659
666 bitmap_stop_daemon(bitmap);
667
668 drain_write_queues(bitmap); 660 drain_write_queues(bitmap);
669 661
670 bitmap_file_unmap(bitmap); 662 bitmap_file_unmap(bitmap);
@@ -770,6 +762,8 @@ static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
770 762
771} 763}
772 764
765static void bitmap_writeback(struct bitmap *bitmap);
766
773/* this gets called when the md device is ready to unplug its underlying 767/* this gets called when the md device is ready to unplug its underlying
774 * (slave) device queues -- before we let any writes go down, we need to 768 * (slave) device queues -- before we let any writes go down, we need to
775 * sync the dirty pages of the bitmap file to disk */ 769 * sync the dirty pages of the bitmap file to disk */
@@ -812,13 +806,9 @@ int bitmap_unplug(struct bitmap *bitmap)
812 } 806 }
813 } 807 }
814 if (wait) { /* if any writes were performed, we need to wait on them */ 808 if (wait) { /* if any writes were performed, we need to wait on them */
815 if (bitmap->file) { 809 if (bitmap->file)
816 spin_lock_irq(&bitmap->write_lock); 810 bitmap_writeback(bitmap);
817 wait_event_lock_irq(bitmap->write_wait, 811 else
818 list_empty(&bitmap->complete_pages), bitmap->write_lock,
819 wake_up_process(bitmap->writeback_daemon->tsk));
820 spin_unlock_irq(&bitmap->write_lock);
821 } else
822 md_super_wait(bitmap->mddev); 812 md_super_wait(bitmap->mddev);
823 } 813 }
824 return 0; 814 return 0;
@@ -1126,41 +1116,12 @@ int bitmap_daemon_work(struct bitmap *bitmap)
1126 return err; 1116 return err;
1127} 1117}
1128 1118
1129static void daemon_exit(struct bitmap *bitmap, mdk_thread_t **daemon) 1119static void bitmap_writeback(struct bitmap *bitmap)
1130{ 1120{
1131 mdk_thread_t *dmn;
1132 unsigned long flags;
1133
1134 /* if no one is waiting on us, we'll free the md thread struct
1135 * and exit, otherwise we let the waiter clean things up */
1136 spin_lock_irqsave(&bitmap->lock, flags);
1137 if ((dmn = *daemon)) { /* no one is waiting, cleanup and exit */
1138 *daemon = NULL;
1139 spin_unlock_irqrestore(&bitmap->lock, flags);
1140 kfree(dmn);
1141 complete_and_exit(NULL, 0); /* do_exit not exported */
1142 }
1143 spin_unlock_irqrestore(&bitmap->lock, flags);
1144}
1145
1146static void bitmap_writeback_daemon(mddev_t *mddev)
1147{
1148 struct bitmap *bitmap = mddev->bitmap;
1149 struct page *page; 1121 struct page *page;
1150 struct page_list *item; 1122 struct page_list *item;
1151 int err = 0; 1123 int err = 0;
1152 1124
1153 if (signal_pending(current)) {
1154 printk(KERN_INFO
1155 "%s: bitmap writeback daemon got signal, exiting...\n",
1156 bmname(bitmap));
1157 err = -EINTR;
1158 goto out;
1159 }
1160 if (bitmap == NULL)
1161 /* about to be stopped. */
1162 return;
1163
1164 PRINTK("%s: bitmap writeback daemon woke up...\n", bmname(bitmap)); 1125 PRINTK("%s: bitmap writeback daemon woke up...\n", bmname(bitmap));
1165 /* wait on bitmap page writebacks */ 1126 /* wait on bitmap page writebacks */
1166 while ((item = dequeue_page(bitmap))) { 1127 while ((item = dequeue_page(bitmap))) {
@@ -1177,59 +1138,9 @@ static void bitmap_writeback_daemon(mddev_t *mddev)
1177 "failed (page %lu): %d\n", 1138 "failed (page %lu): %d\n",
1178 bmname(bitmap), page->index, err); 1139 bmname(bitmap), page->index, err);
1179 bitmap_file_kick(bitmap); 1140 bitmap_file_kick(bitmap);
1180 goto out; 1141 break;
1181 } 1142 }
1182 } 1143 }
1183 out:
1184 wake_up(&bitmap->write_wait);
1185 if (err) {
1186 printk(KERN_INFO "%s: bitmap writeback daemon exiting (%d)\n",
1187 bmname(bitmap), err);
1188 daemon_exit(bitmap, &bitmap->writeback_daemon);
1189 }
1190}
1191
1192static mdk_thread_t *bitmap_start_daemon(struct bitmap *bitmap,
1193 void (*func)(mddev_t *), char *name)
1194{
1195 mdk_thread_t *daemon;
1196 char namebuf[32];
1197
1198#ifdef INJECT_FATAL_FAULT_2
1199 daemon = NULL;
1200#else
1201 sprintf(namebuf, "%%s_%s", name);
1202 daemon = md_register_thread(func, bitmap->mddev, namebuf);
1203#endif
1204 if (!daemon) {
1205 printk(KERN_ERR "%s: failed to start bitmap daemon\n",
1206 bmname(bitmap));
1207 return ERR_PTR(-ECHILD);
1208 }
1209
1210 md_wakeup_thread(daemon); /* start it running */
1211
1212 PRINTK("%s: %s daemon (pid %d) started...\n",
1213 bmname(bitmap), name, daemon->tsk->pid);
1214
1215 return daemon;
1216}
1217
1218static void bitmap_stop_daemon(struct bitmap *bitmap)
1219{
1220 /* the daemon can't stop itself... it'll just exit instead... */
1221 if (bitmap->writeback_daemon && ! IS_ERR(bitmap->writeback_daemon) &&
1222 current->pid != bitmap->writeback_daemon->tsk->pid) {
1223 mdk_thread_t *daemon;
1224 unsigned long flags;
1225
1226 spin_lock_irqsave(&bitmap->lock, flags);
1227 daemon = bitmap->writeback_daemon;
1228 bitmap->writeback_daemon = NULL;
1229 spin_unlock_irqrestore(&bitmap->lock, flags);
1230 if (daemon && ! IS_ERR(daemon))
1231 md_unregister_thread(daemon); /* destroy the thread */
1232 }
1233} 1144}
1234 1145
1235static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap, 1146static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
@@ -1553,7 +1464,6 @@ int bitmap_create(mddev_t *mddev)
1553 1464
1554 spin_lock_init(&bitmap->write_lock); 1465 spin_lock_init(&bitmap->write_lock);
1555 INIT_LIST_HEAD(&bitmap->complete_pages); 1466 INIT_LIST_HEAD(&bitmap->complete_pages);
1556 init_waitqueue_head(&bitmap->write_wait);
1557 bitmap->write_pool = mempool_create_kmalloc_pool(WRITE_POOL_SIZE, 1467 bitmap->write_pool = mempool_create_kmalloc_pool(WRITE_POOL_SIZE,
1558 sizeof(struct page_list)); 1468 sizeof(struct page_list));
1559 err = -ENOMEM; 1469 err = -ENOMEM;
@@ -1613,15 +1523,6 @@ int bitmap_create(mddev_t *mddev)
1613 1523
1614 mddev->bitmap = bitmap; 1524 mddev->bitmap = bitmap;
1615 1525
1616 if (file)
1617 /* kick off the bitmap writeback daemon */
1618 bitmap->writeback_daemon =
1619 bitmap_start_daemon(bitmap,
1620 bitmap_writeback_daemon,
1621 "bitmap_wb");
1622
1623 if (IS_ERR(bitmap->writeback_daemon))
1624 return PTR_ERR(bitmap->writeback_daemon);
1625 mddev->thread->timeout = bitmap->daemon_sleep * HZ; 1526 mddev->thread->timeout = bitmap->daemon_sleep * HZ;
1626 1527
1627 return bitmap_update_sb(bitmap); 1528 return bitmap_update_sb(bitmap);
diff --git a/include/linux/raid/bitmap.h b/include/linux/raid/bitmap.h
index 899437802aea..9c8907ca60a7 100644
--- a/include/linux/raid/bitmap.h
+++ b/include/linux/raid/bitmap.h
@@ -244,13 +244,7 @@ struct bitmap {
244 unsigned long daemon_lastrun; /* jiffies of last run */ 244 unsigned long daemon_lastrun; /* jiffies of last run */
245 unsigned long daemon_sleep; /* how many seconds between updates? */ 245 unsigned long daemon_sleep; /* how many seconds between updates? */
246 246
247 /*
248 * bitmap_writeback_daemon waits for file-pages that have been written,
249 * as there is no way to get a call-back when a page write completes.
250 */
251 mdk_thread_t *writeback_daemon;
252 spinlock_t write_lock; 247 spinlock_t write_lock;
253 wait_queue_head_t write_wait;
254 struct list_head complete_pages; 248 struct list_head complete_pages;
255 mempool_t *write_pool; 249 mempool_t *write_pool;
256}; 250};