From: Stefan Haberland <sth@linux.ibm.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org,
Jan Hoeppner <hoeppner@linux.ibm.com>,
linux-s390@vger.kernel.org, Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>
Subject: [PATCH 05/19] s390/dasd: Optimize max blocks per request for track alignment
Date: Wed, 5 Aug 2026 13:15:58 +0200 [thread overview]
Message-ID: <20260805111612.1285190-6-sth@linux.ibm.com> (raw)
In-Reply-To: <20260805111612.1285190-1-sth@linux.ibm.com>
With 4096-byte blocks a full ECKD track holds exactly 12 records. Lower
DASD_ECKD_MAX_BLOCKS from 190 to 180 so requests align to track
boundaries (15 full tracks); full-track I/O is more efficient than
partial-track writes, and 190 had no alignment significance and could
let a request cross a track boundary.
Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
---
drivers/s390/block/dasd_eckd.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/s390/block/dasd_eckd.h b/drivers/s390/block/dasd_eckd.h
index f9299bd184ba..763733bcc4d2 100644
--- a/drivers/s390/block/dasd_eckd.h
+++ b/drivers/s390/block/dasd_eckd.h
@@ -131,7 +131,7 @@
/*
* Maximum number of blocks to be chained
*/
-#define DASD_ECKD_MAX_BLOCKS 190
+#define DASD_ECKD_MAX_BLOCKS 180
#define DASD_ECKD_MAX_BLOCKS_RAW 256
/*****************************************************************************
--
2.53.0
next prev parent reply other threads:[~2026-08-05 11:16 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-05 11:15 [PATCH 00/19] s390/dasd: ESE Performance improvements Stefan Haberland
2026-08-05 11:15 ` [PATCH 01/19] s390/dasd: Do not complete a failed ESE read as successful Stefan Haberland
2026-08-05 11:15 ` [PATCH 02/19] s390/dasd: Propagate partial completion length across ERP recovery Stefan Haberland
2026-08-05 11:15 ` [PATCH 03/19] s390/dasd: Guard sysfs discipline callbacks against unallocated private data Stefan Haberland
2026-08-05 11:15 ` [PATCH 04/19] s390/dasd: Snapshot intrc before freeing the request block Stefan Haberland
2026-08-05 11:15 ` Stefan Haberland [this message]
2026-08-05 11:15 ` [PATCH 06/19] s390/dasd: Use GFP_KERNEL in dasd_alloc_device() Stefan Haberland
2026-08-05 11:16 ` [PATCH 07/19] s390/dasd: Add defines for the Extended Address Volume track address Stefan Haberland
2026-08-05 11:16 ` [PATCH 08/19] s390/dasd: Add infrastructure for ESE full-track write Stefan Haberland
2026-08-05 11:16 ` [PATCH 09/19] s390/dasd: Add range-based format-track collision detection Stefan Haberland
2026-08-05 11:16 ` [PATCH 10/19] s390/dasd: Extend prepare_itcw() to support WRITE_FULL_TRACK Stefan Haberland
2026-08-05 11:16 ` [PATCH 11/19] s390/dasd: Add dasd_eckd_build_cp_tpm_writefulltrack() Stefan Haberland
2026-08-05 11:16 ` [PATCH 12/19] s390/dasd: Use WRITE_FULL_TRACK in ESE format handler Stefan Haberland
2026-08-05 11:16 ` [PATCH 13/19] s390/dasd: Add full_track_bias to control fulltrack write mode Stefan Haberland
2026-08-05 11:16 ` [PATCH 14/19] s390/dasd: Derive adaptive ESE fulltrack heuristic from ft_bias Stefan Haberland
2026-08-05 11:16 ` [PATCH 15/19] s390/dasd: Stamp a format label into newly formatted volumes Stefan Haberland
2026-08-05 11:16 ` [PATCH 16/19] s390/dasd: Detect ESE volumes from the on-disk format label Stefan Haberland
2026-08-05 11:16 ` [PATCH 17/19] s390/dasd: Report ESE capability and format mode at device online Stefan Haberland
2026-08-05 11:16 ` [PATCH 18/19] s390/dasd: Re-enable discard support for ESE volumes Stefan Haberland
2026-08-05 11:16 ` [PATCH 19/19] s390/dasd: Read cached unit address and LSS in the CCW build path Stefan Haberland
2026-08-05 12:32 ` [PATCH 00/19] s390/dasd: ESE Performance improvements Jens Axboe
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