[PATCH] Dynamic RAID Stripe Cache Size
DORMANTno replies
From: Yuri Tikhonov <hidden>
Date: 2008-02-07 12:41:01
Subsystem:
software raid (multiple disks) support, the rest · Maintainers:
Song Liu, Yu Kuai, Linus Torvalds
Hello, On platforms with PAGE_SIZE set to rather big values (e.g. 256KB) the amount of memory necessary for for the stripe cache may be significant, so we can't rely on the hard-coded value of initial max_nr_stripes (this may cause invoking OOM-killer for terminating RAID creation process). What this patch does is just checks the size of available memory, and assigns the appropriate, safe, value to initial max_nr_stripes: either the hard-coded NR_STRIPES value if it's safe in the sense that we'll have some free memory available using stripe cache with such size, or the calculated, lesser, value. Signed-off-by: Yuri Tikhonov <redacted> --
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index d59e1bc..1d2b064 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c@@ -4934,10 +4934,11 @@ static struct attribute_group raid5_attrs_group = { static int run(mddev_t *mddev) { raid5_conf_t *conf; - int raid_disk, memory; + int raid_disk, memory, avail_stripes; mdk_rdev_t *rdev; struct disk_info *disk; struct list_head *tmp; + struct sysinfo val; int working_disks = 0; if (mddev->level != 5 && mddev->level != 4 && mddev->level != 6) {
@@ -5074,7 +5075,14 @@ static int run(mddev_t *mddev) else conf->max_degraded = 1; conf->algorithm = mddev->layout; - conf->max_nr_stripes = NR_STRIPES; + + /* Set the safe stripe cache size */ + si_meminfo(&val); + avail_stripes = (val.freeram + val.freehigh) * val.mem_unit / + (sizeof(struct stripe_head) + conf->raid_disks * + ((sizeof(struct bio) + PAGE_SIZE))) - 1; + conf->max_nr_stripes = (avail_stripes < NR_STRIPES) ? avail_stripes : + NR_STRIPES; conf->expand_progress = mddev->reshape_position; /* device size must be a multiple of chunk size */
--
Yuri Tikhonov, Senior Software Engineer
Emcraft Systems, www.emcraft.com