From 18d758a2d81a97b9a54a37d535870ce3170cc208 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Fri, 17 Feb 2023 13:37:03 +0800 Subject: btrfs: replace btrfs_io_context::raid_map with a fixed u64 value In btrfs_io_context structure, we have a pointer raid_map, which indicates the logical bytenr for each stripe. But considering we always call sort_parity_stripes(), the result raid_map[] is always sorted, thus raid_map[0] is always the logical bytenr of the full stripe. So why we waste the space and time (for sorting) for raid_map? This patch will replace btrfs_io_context::raid_map with a single u64 number, full_stripe_start, by: - Replace btrfs_io_context::raid_map with full_stripe_start - Replace call sites using raid_map[0] to use full_stripe_start - Replace call sites using raid_map[i] to compare with nr_data_stripes. The benefits are: - Less memory wasted on raid_map It's sizeof(u64) * num_stripes vs sizeof(u64). It'll always save at least one u64, and the benefit grows larger with num_stripes. - No more weird alloc_btrfs_io_context() behavior As there is only one fixed size + one variable length array. Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- include/trace/events/btrfs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/trace') diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h index 75d7d22c3a27..8ea9cea9bfeb 100644 --- a/include/trace/events/btrfs.h +++ b/include/trace/events/btrfs.h @@ -2422,7 +2422,7 @@ DECLARE_EVENT_CLASS(btrfs_raid56_bio, ), TP_fast_assign_btrfs(rbio->bioc->fs_info, - __entry->full_stripe = rbio->bioc->raid_map[0]; + __entry->full_stripe = rbio->bioc->full_stripe_logical; __entry->physical = bio->bi_iter.bi_sector << SECTOR_SHIFT; __entry->len = bio->bi_iter.bi_size; __entry->opf = bio_op(bio); -- cgit v1.2.3