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Wed, 5 Aug 2026 11:16:17 +0000 (GMT) From: Stefan Haberland To: Jens Axboe Cc: linux-block@vger.kernel.org, Jan Hoeppner , linux-s390@vger.kernel.org, Heiko Carstens , Vasily Gorbik , Christian Borntraeger Subject: [PATCH 05/19] s390/dasd: Optimize max blocks per request for track alignment Date: Wed, 5 Aug 2026 13:15:58 +0200 Message-ID: <20260805111612.1285190-6-sth@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260805111612.1285190-1-sth@linux.ibm.com> References: <20260805111612.1285190-1-sth@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=E6P9Y6dl c=1 sm=1 tr=0 ts=6a731b88 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VnNF1IyMAAAA:8 a=8f17mpASHZ0i51vZi0YA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-ORIG-GUID: eohPgSB3xjQpL-3mKLQWEnGLSYi6fr_q X-Proofpoint-GUID: eohPgSB3xjQpL-3mKLQWEnGLSYi6fr_q X-Proofpoint-Spam-Info: AW1haW4tMjYwODA1MDA4NiBTYWx0ZWRfX/up+JZzU4IDL 5bFMXzVXD+vMjxgOiBidu/lJQVDb1TRGRptA51VzYBghOWRifGbZ2tJRWWo+GejHw/d+FvvEcL+ oOBj9nYv8J32YY7HzhBgUwduX4opqpg= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODA1MDA4NiBTYWx0ZWRfXxDJhCRWX2N16 LWiFTdVHLHQ8rXG1IDU2Exn4yOCje1gksma4oWXc/EtS8Gyg35KPyBQG9b5iyw/uQDhwL0GPSWP 0NsJ4yJ737SCzYTYqadtYdg++Tb6HwPm35VxDSD4X6LYC53CtgzwKqmBhuTEHvqeuXcjv7jNOZl kDPv7Z332p715Y7jv6+zShUrSi8N9zSN2zjXVbfvUApeNZSCHmkqu0zByN3SbKFEkTgJDczmY7Y sFm/K+uLCTqZKsKrWwkADLmnZV0u/fd+fVVAQwil9bjD6R5nAEIDm+09bK8YMxwqjzUSHxypQvA LdCtGqIMAb4CQy5JHaQNyM4EhkFWLubEQUvhDwHC7xmFe+cbmT/Zd3pGGrB0Tv8BYNsmEjkNN5F qsFawjTu2w/t9b20jR88vAPx6b4FFCuzqBnkmsOvl9bzVs9JXrDtbq/H/h0qVoUH6SDw4lHggXc GD3h43FQJ8vo8nVR4hg== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-05_03,2026-08-04_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 clxscore=1015 lowpriorityscore=0 priorityscore=1501 suspectscore=0 adultscore=0 spamscore=0 malwarescore=0 impostorscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608050086 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 Signed-off-by: Stefan Haberland --- 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