From: Yu Kuai Date: Wed, 14 Jan 2026 17:12:33 +0000 (+0800) Subject: md/raid5: use mempool to allocate stripe_request_ctx X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9340a95d489ab5ff3c2d18c78283211b03a4265a;p=thirdparty%2Fkernel%2Flinux.git md/raid5: use mempool to allocate stripe_request_ctx On the one hand, stripe_request_ctx is 72 bytes, and it's a bit huge for a stack variable. On the other hand, the bitmap sectors_to_do is a fixed size, result in max_hw_sector_kb of raid5 array is at most 256 * 4k = 1Mb, and this will make full stripe IO impossible for the array that chunk_size * data_disks is bigger. Allocate ctx during runtime will make it possible to get rid of this limit. Link: https://lore.kernel.org/linux-raid/20260114171241.3043364-6-yukuai@fnnas.com Signed-off-by: Yu Kuai Reviewed-by: Li Nan --- diff --git a/drivers/md/md.h b/drivers/md/md.h index 6ee18045f41c3..b8c5dec12b62f 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -22,6 +22,10 @@ #include #define MaxSector (~(sector_t)0) +/* + * Number of guaranteed raid bios in case of extreme VM load: + */ +#define NR_RAID_BIOS 256 enum md_submodule_type { MD_PERSONALITY = 0, diff --git a/drivers/md/raid1-10.c b/drivers/md/raid1-10.c index 521625756128a..c33099925f230 100644 --- a/drivers/md/raid1-10.c +++ b/drivers/md/raid1-10.c @@ -3,11 +3,6 @@ #define RESYNC_BLOCK_SIZE (64*1024) #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE) -/* - * Number of guaranteed raid bios in case of extreme VM load: - */ -#define NR_RAID_BIOS 256 - /* when we get a read error on a read-only array, we redirect to another * device without failing the first device, or trying to over-write to * correct the read error. To keep track of bad blocks on a per-bio diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 6d44609f62f30..2fa63bd2431aa 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -6084,13 +6084,13 @@ static sector_t raid5_bio_lowest_chunk_sector(struct r5conf *conf, static bool raid5_make_request(struct mddev *mddev, struct bio * bi) { DEFINE_WAIT_FUNC(wait, woken_wake_function); - bool on_wq; struct r5conf *conf = mddev->private; - sector_t logical_sector; - struct stripe_request_ctx ctx = {}; const int rw = bio_data_dir(bi); + struct stripe_request_ctx *ctx; + sector_t logical_sector; enum stripe_result res; int s, stripe_cnt; + bool on_wq; if (unlikely(bi->bi_opf & REQ_PREFLUSH)) { int ret = log_handle_flush_request(conf, bi); @@ -6102,11 +6102,6 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi) return true; } /* ret == -EAGAIN, fallback */ - /* - * if r5l_handle_flush_request() didn't clear REQ_PREFLUSH, - * we need to flush journal device - */ - ctx.do_flush = bi->bi_opf & REQ_PREFLUSH; } md_write_start(mddev, bi); @@ -6129,16 +6124,25 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi) } logical_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1); - ctx.first_sector = logical_sector; - ctx.last_sector = bio_end_sector(bi); bi->bi_next = NULL; - stripe_cnt = DIV_ROUND_UP_SECTOR_T(ctx.last_sector - logical_sector, + ctx = mempool_alloc(conf->ctx_pool, GFP_NOIO); + memset(ctx, 0, sizeof(*ctx)); + ctx->first_sector = logical_sector; + ctx->last_sector = bio_end_sector(bi); + /* + * if r5l_handle_flush_request() didn't clear REQ_PREFLUSH, + * we need to flush journal device + */ + if (unlikely(bi->bi_opf & REQ_PREFLUSH)) + ctx->do_flush = true; + + stripe_cnt = DIV_ROUND_UP_SECTOR_T(ctx->last_sector - logical_sector, RAID5_STRIPE_SECTORS(conf)); - bitmap_set(ctx.sectors_to_do, 0, stripe_cnt); + bitmap_set(ctx->sectors_to_do, 0, stripe_cnt); pr_debug("raid456: %s, logical %llu to %llu\n", __func__, - bi->bi_iter.bi_sector, ctx.last_sector); + bi->bi_iter.bi_sector, ctx->last_sector); /* Bail out if conflicts with reshape and REQ_NOWAIT is set */ if ((bi->bi_opf & REQ_NOWAIT) && @@ -6146,6 +6150,7 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi) bio_wouldblock_error(bi); if (rw == WRITE) md_write_end(mddev); + mempool_free(ctx, conf->ctx_pool); return true; } md_account_bio(mddev, &bi); @@ -6164,10 +6169,10 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi) add_wait_queue(&conf->wait_for_reshape, &wait); on_wq = true; } - s = (logical_sector - ctx.first_sector) >> RAID5_STRIPE_SHIFT(conf); + s = (logical_sector - ctx->first_sector) >> RAID5_STRIPE_SHIFT(conf); while (1) { - res = make_stripe_request(mddev, conf, &ctx, logical_sector, + res = make_stripe_request(mddev, conf, ctx, logical_sector, bi); if (res == STRIPE_FAIL || res == STRIPE_WAIT_RESHAPE) break; @@ -6184,9 +6189,9 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi) * raid5_activate_delayed() from making progress * and thus deadlocking. */ - if (ctx.batch_last) { - raid5_release_stripe(ctx.batch_last); - ctx.batch_last = NULL; + if (ctx->batch_last) { + raid5_release_stripe(ctx->batch_last); + ctx->batch_last = NULL; } wait_woken(&wait, TASK_UNINTERRUPTIBLE, @@ -6194,21 +6199,23 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi) continue; } - s = find_next_bit_wrap(ctx.sectors_to_do, stripe_cnt, s); + s = find_next_bit_wrap(ctx->sectors_to_do, stripe_cnt, s); if (s == stripe_cnt) break; - logical_sector = ctx.first_sector + + logical_sector = ctx->first_sector + (s << RAID5_STRIPE_SHIFT(conf)); } if (unlikely(on_wq)) remove_wait_queue(&conf->wait_for_reshape, &wait); - if (ctx.batch_last) - raid5_release_stripe(ctx.batch_last); + if (ctx->batch_last) + raid5_release_stripe(ctx->batch_last); if (rw == WRITE) md_write_end(mddev); + + mempool_free(ctx, conf->ctx_pool); if (res == STRIPE_WAIT_RESHAPE) { md_free_cloned_bio(bi); return false; @@ -7378,6 +7385,9 @@ static void free_conf(struct r5conf *conf) bioset_exit(&conf->bio_split); kfree(conf->stripe_hashtbl); kfree(conf->pending_data); + + mempool_destroy(conf->ctx_pool); + kfree(conf); } @@ -8061,6 +8071,13 @@ static int raid5_run(struct mddev *mddev) goto abort; } + conf->ctx_pool = mempool_create_kmalloc_pool(NR_RAID_BIOS, + sizeof(struct stripe_request_ctx)); + if (!conf->ctx_pool) { + ret = -ENOMEM; + goto abort; + } + ret = log_init(conf, journal_dev, raid5_has_ppl(conf)); if (ret) goto abort; diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h index eafc6e9ed6ee1..6e3f07119fa4a 100644 --- a/drivers/md/raid5.h +++ b/drivers/md/raid5.h @@ -690,6 +690,8 @@ struct r5conf { struct list_head pending_list; int pending_data_cnt; struct r5pending_data *next_pending_data; + + mempool_t *ctx_pool; }; #if PAGE_SIZE == DEFAULT_STRIPE_SIZE