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authorJon Derrick <jonathan.derrick@linux.dev>2023-02-24 11:33:23 -0700
committerSong Liu <song@kernel.org>2023-04-13 22:20:24 -0700
commit8745faa95611f6331331284925012c0310ae3e2c (patch)
tree5b7b8297da17ce7643f3b30a697d6337738acff5 /drivers/md
parent10172f200b67aafcb9b8ce7d0575d713c1aafbb7 (diff)
md: Use optimal I/O size for last bitmap page
If the bitmap space has enough room, size the I/O for the last bitmap page write to the optimal I/O size for the storage device. The expanded write is checked that it won't overrun the data or metadata. The drive this was tested against has higher latencies when there are sub-4k writes due to device-side read-mod-writes of its atomic 4k write unit. This change helps increase performance by sizing the last bitmap page I/O for the device's preferred write unit, if it is given. Example Intel/Solidigm P5520 Raid10, Chunk-size 64M, bitmap-size 57228 bits $ mdadm --create /dev/md0 --level=10 --raid-devices=4 /dev/nvme{0,1,2,3}n1 --assume-clean --bitmap=internal --bitmap-chunk=64M $ fio --name=test --direct=1 --filename=/dev/md0 --rw=randwrite --bs=4k --runtime=60 Without patch: write: IOPS=1676, BW=6708KiB/s (6869kB/s)(393MiB/60001msec); 0 zone resets With patch: write: IOPS=15.7k, BW=61.4MiB/s (64.4MB/s)(3683MiB/60001msec); 0 zone resets Biosnoop: Without patch: Time Process PID Device LBA Size Lat 1.410377 md0_raid10 6900 nvme0n1 W 16 4096 0.02 1.410387 md0_raid10 6900 nvme2n1 W 16 4096 0.02 1.410374 md0_raid10 6900 nvme3n1 W 16 4096 0.01 1.410381 md0_raid10 6900 nvme1n1 W 16 4096 0.02 1.410411 md0_raid10 6900 nvme1n1 W 115346512 4096 0.01 1.410418 md0_raid10 6900 nvme0n1 W 115346512 4096 0.02 1.410915 md0_raid10 6900 nvme2n1 W 24 3584 0.43 <-- 1.410935 md0_raid10 6900 nvme3n1 W 24 3584 0.45 <-- 1.411124 md0_raid10 6900 nvme1n1 W 24 3584 0.64 <-- 1.411147 md0_raid10 6900 nvme0n1 W 24 3584 0.66 <-- 1.411176 md0_raid10 6900 nvme3n1 W 2019022184 4096 0.01 1.411189 md0_raid10 6900 nvme2n1 W 2019022184 4096 0.02 With patch: Time Process PID Device LBA Size Lat 5.747193 md0_raid10 727 nvme0n1 W 16 4096 0.01 5.747192 md0_raid10 727 nvme1n1 W 16 4096 0.02 5.747195 md0_raid10 727 nvme3n1 W 16 4096 0.01 5.747202 md0_raid10 727 nvme2n1 W 16 4096 0.02 5.747229 md0_raid10 727 nvme3n1 W 1196223704 4096 0.02 5.747224 md0_raid10 727 nvme0n1 W 1196223704 4096 0.01 5.747279 md0_raid10 727 nvme0n1 W 24 4096 0.01 <-- 5.747279 md0_raid10 727 nvme1n1 W 24 4096 0.02 <-- 5.747284 md0_raid10 727 nvme3n1 W 24 4096 0.02 <-- 5.747291 md0_raid10 727 nvme2n1 W 24 4096 0.02 <-- 5.747314 md0_raid10 727 nvme2n1 W 2234636712 4096 0.01 5.747317 md0_raid10 727 nvme1n1 W 2234636712 4096 0.02 Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jon Derrick <jonathan.derrick@linux.dev> Signed-off-by: Song Liu <song@kernel.org> Link: https://lore.kernel.org/r/20230224183323.638-4-jonathan.derrick@linux.dev
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/md-bitmap.c33
1 files changed, 29 insertions, 4 deletions
diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index bf250a5e3a86..920bb68156d2 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -209,6 +209,28 @@ static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mdde
return NULL;
}
+static unsigned int optimal_io_size(struct block_device *bdev,
+ unsigned int last_page_size,
+ unsigned int io_size)
+{
+ if (bdev_io_opt(bdev) > bdev_logical_block_size(bdev))
+ return roundup(last_page_size, bdev_io_opt(bdev));
+ return io_size;
+}
+
+static unsigned int bitmap_io_size(unsigned int io_size, unsigned int opt_size,
+ sector_t start, sector_t boundary)
+{
+ if (io_size != opt_size &&
+ start + opt_size / SECTOR_SIZE <= boundary)
+ return opt_size;
+ if (start + io_size / SECTOR_SIZE <= boundary)
+ return io_size;
+
+ /* Overflows boundary */
+ return 0;
+}
+
static int __write_sb_page(struct md_rdev *rdev, struct bitmap *bitmap,
struct page *page)
{
@@ -218,6 +240,7 @@ static int __write_sb_page(struct md_rdev *rdev, struct bitmap *bitmap,
sector_t offset = mddev->bitmap_info.offset;
sector_t ps, sboff, doff;
unsigned int size = PAGE_SIZE;
+ unsigned int opt_size = PAGE_SIZE;
bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
if (page->index == store->file_pages - 1) {
@@ -225,8 +248,8 @@ static int __write_sb_page(struct md_rdev *rdev, struct bitmap *bitmap,
if (last_page_size == 0)
last_page_size = PAGE_SIZE;
- size = roundup(last_page_size,
- bdev_logical_block_size(bdev));
+ size = roundup(last_page_size, bdev_logical_block_size(bdev));
+ opt_size = optimal_io_size(bdev, last_page_size, size);
}
ps = page->index * PAGE_SIZE / SECTOR_SIZE;
@@ -241,7 +264,8 @@ static int __write_sb_page(struct md_rdev *rdev, struct bitmap *bitmap,
return -EINVAL;
} else if (offset < 0) {
/* DATA BITMAP METADATA */
- if (offset + ps + size / SECTOR_SIZE > 0)
+ size = bitmap_io_size(size, opt_size, offset + ps, 0);
+ if (size == 0)
/* bitmap runs in to metadata */
return -EINVAL;
@@ -250,7 +274,8 @@ static int __write_sb_page(struct md_rdev *rdev, struct bitmap *bitmap,
return -EINVAL;
} else if (rdev->sb_start < rdev->data_offset) {
/* METADATA BITMAP DATA */
- if (sboff + ps + size / SECTOR_SIZE > doff)
+ size = bitmap_io_size(size, opt_size, sboff + ps, doff);
+ if (size == 0)
/* bitmap runs in to data */
return -EINVAL;
} else {