land b1_5 onto HEAD

[fs/lustre-release.git] / lustre / kernel_patches / patches / raid5-configurable-cachesize.patch

diff --git a/lustre/kernel_patches/patches/raid5-configurable-cachesize.patch b/lustre/kernel_patches/patches/raid5-configurable-cachesize.patch
new file mode 100644 (file)
index 0000000..7045872
--- /dev/null
+++ b/lustre/kernel_patches/patches/raid5-configurable-cachesize.patch
@@ -0,0 +1,50 @@
+Adds a module parameter to control raid5's internal cache size.
+
+Index: linux-2.6.9/drivers/md/raid5.c
+===================================================================
+--- linux-2.6.9.orig/drivers/md/raid5.c        2006-05-21 17:57:25.000000000 +0400
++++ linux-2.6.9/drivers/md/raid5.c     2006-05-22 00:01:30.000000000 +0400
+@@ -28,7 +28,8 @@
+  * Stripe cache
+  */
+ 
+-#define NR_STRIPES            256
++static int raid5_nr_stripes = 256 * 8;
++
+ #define STRIPE_SIZE           PAGE_SIZE
+ #define STRIPE_SHIFT          (PAGE_SHIFT - 9)
+ #define STRIPE_SECTORS                (STRIPE_SIZE>>9)
+@@ -92,7 +93,7 @@ static inline void __release_stripe(raid
+                       list_add_tail(&sh->lru, &conf->inactive_list);
+                       atomic_dec(&conf->active_stripes);
+                       if (!conf->inactive_blocked ||
+-                          atomic_read(&conf->active_stripes) < (NR_STRIPES*3/4))
++                          atomic_read(&conf->active_stripes) < (conf->max_nr_stripes*3/4))
+                               wake_up(&conf->wait_for_stripe);
+               }
+       }
+@@ -255,7 +256,7 @@ static struct stripe_head *get_active_st
+                               conf->inactive_blocked = 1;
+                               wait_event_lock_irq(conf->wait_for_stripe,
+                                                   !list_empty(&conf->inactive_list) &&
+-                                                  (atomic_read(&conf->active_stripes) < (NR_STRIPES *3/4)
++                                                  (atomic_read(&conf->active_stripes) < (conf->max_nr_stripes *3/4)
+                                                    || !conf->inactive_blocked),
+                                                   conf->device_lock,
+                                                   unplug_slaves(conf->mddev);
+@@ -1637,7 +1638,7 @@ static int run (mddev_t *mddev)
+       conf->chunk_size = mddev->chunk_size;
+       conf->level = mddev->level;
+       conf->algorithm = mddev->layout;
+-      conf->max_nr_stripes = NR_STRIPES;
++      conf->max_nr_stripes = raid5_nr_stripes;
+ 
+       /* device size must be a multiple of chunk size */
+       mddev->size &= ~(mddev->chunk_size/1024 -1);
+@@ -1957,5 +1958,6 @@ static void raid5_exit (void)
+ 
+ module_init(raid5_init);
+ module_exit(raid5_exit);
++module_param(raid5_nr_stripes, int, 0644);
+ MODULE_LICENSE("GPL");
+ MODULE_ALIAS("md-personality-4"); /* RAID5 */