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Sat, 1 Aug 2026 11:10:17 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.87.85.9]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTP; Sat, 1 Aug 2026 11:10:16 +0000 (GMT) From: Stefan Haberland To: linux-s390@vger.kernel.org Cc: Jan Hoeppner , Eduard Shishkin Subject: [PATCH v6 04/18] s390/dasd: Optimize max blocks per request for track alignment Date: Sat, 1 Aug 2026 13:09:54 +0200 Message-ID: <20260801111008.3391031-5-sth@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260801111008.3391031-1-sth@linux.ibm.com> References: <20260801111008.3391031-1-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-Proofpoint-ORIG-GUID: LM1__FSaYmkHc-XI95IGV8ExgeWGGEzv X-Proofpoint-Spam-Info: AW1haW4tMjYwODAxMDA4MyBTYWx0ZWRfX8/ADJh5vYQhP IsUz5/tbodoT23UHc4KqIg0ffZp55j+Chb8cmuzKso/gcIwvB+q2ANhCmfJWGMmET0tYMxvIRmn ptpNYu47hZNbKuiTxHpqePRriaW3WCA= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODAxMDA4MyBTYWx0ZWRfX1S5nzztZvJeu lpSNGCLiHahRWRJmJww3Zo5lfKbvJmG9/RjyPXOVmgOU8krp8f2+txdlrqmzXj5/Mo7isXbTB2t DleJYrDbhgJONBJ57KZMYeku3/v9TXEIK5r5fcX3UMcZwWouI1lTF+mj1FmI+PYzdTrQCoadFeI GTbKrY2JFM8WVq8INOn99CuCVQSFLW7JneNx3G2M2FG0lcFxOZDGxfWj3KLlYeaTmjICLSLVwAu 33Ysv04D68p5s15yetBPf64c5h52yJh6v6l6O03hmpBaRLUECJ5dOn1aMe+Sx9B3bcRa3uYW0Ev Hkr7QrAseZ3JTXHRbEWNYk2aoL3W5YAnj0moXWMARB42tj1GUjZ/mz7P1fpP3VFYnYfFhZ1/eYW 7Ns+aoecj4UIjQcR+5/reke3WNUU5LtLUWm+q6D2ice6NWnWVg9X8Sh/DQB0RGp1W3gjLUJ+pBu //6XHNl/uq1+WgW4Rxg== X-Proofpoint-GUID: LM1__FSaYmkHc-XI95IGV8ExgeWGGEzv X-Authority-Analysis: v=2.4 cv=KfzidwYD c=1 sm=1 tr=0 ts=6a6dd41d cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VnNF1IyMAAAA:8 a=8f17mpASHZ0i51vZi0YA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-31_07,2026-07-30_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 bulkscore=0 impostorscore=0 suspectscore=0 malwarescore=0 adultscore=0 clxscore=1015 priorityscore=1501 phishscore=0 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608010083 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