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Sun, 18 May 2025 03:44:17 GMT Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8499720074; Sun, 18 May 2025 03:44:17 +0000 (GMT) Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0E72120073; Sun, 18 May 2025 03:44:14 +0000 (GMT) Received: from li-c439904c-24ed-11b2-a85c-b284a6847472.ibm.com.com (unknown [9.43.51.82]) by smtpav03.fra02v.mail.ibm.com (Postfix) with ESMTP; Sun, 18 May 2025 03:44:13 +0000 (GMT) From: Madhavan Srinivasan To: Michael Ellerman , Nicholas Piggin , Naveen N Rao , Christophe Leroy Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH] powerpc/8xx: Reduce alignment constraint for kernel memory Date: Sun, 18 May 2025 09:14:12 +0530 Message-ID: <174753967071.24504.9586296033974318959.b4-ty@linux.ibm.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@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-GUID: 4vpa6_uEN1omYsOffSbEmaSfDzUF8jHI X-Authority-Analysis: v=2.4 cv=eqbfzppX c=1 sm=1 tr=0 ts=68295794 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=IkcTkHD0fZMA:10 a=dt9VzEwgFbYA:10 a=VwQbUJbxAAAA:8 a=7tT5fclhQtEb4bBdwg8A:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNTE4MDAzMSBTYWx0ZWRfXyRYq0HL3s+l/ //fdGoqlj6Bitw2BXaleBDYgWFi89vxy042t43lo+qDINFlatAU75GwhUu3nWFIhk7Wusp+Ot/J hp0p1Q0FEK7jWSQgW8yyvv4wdjQ+EQxk9dc+ALWqYqkXjgO5VncTk6Hv3QChNxo3Kk2gCOVxppT nwKOM5+C4J6pS4feN0zOgaCx+PnaIxmwUhm/SJJTcLJG98H1+DrflZ/BLvJSKdV70/tQpwmxIKc xcu4fXqtYAenAwY7/Vs71/1Cd3JnreAwYO9occqniCo4gY/nrxjjQpOPJiUacz+9jISIDe7OPzN ox797fxUo/ERYgMSLNU2vbw8Bmu9RSTJmNJPD4a6b/6EJM8XCTJG9bSIC3ZnnV972jdgB/YoQQk VoWfZvrGsdWuLw1bpMnIg/bkIzxeowVU5DxPwGpRuxEQQbn55lkj5ysO1NoQSy6TRsT5acxV X-Proofpoint-ORIG-GUID: h0u5K8pC1MWri0qOKGMHnZw1Oq2Klx9i X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.0.736,FMLib:17.12.80.40 definitions=2025-05-18_02,2025-05-16_03,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 malwarescore=0 suspectscore=0 clxscore=1015 bulkscore=0 phishscore=0 priorityscore=1501 lowpriorityscore=0 mlxlogscore=729 mlxscore=0 spamscore=0 adultscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2505070000 definitions=main-2505180031 On Fri, 02 May 2025 15:07:53 +0200, Christophe Leroy wrote: > 8xx has three large page sizes: 8M, 512k and 16k. > > A too big alignment can lead to wasting memory. On a board which has > only 32 MBytes of RAM, every single byte is worth it and a 512k > alignment is sometimes too much. > > Allow mapping kernel memory with 16k pages and reduce the constraint > on kernel memory alignment. 512k and 16k pages are handled the same > way so reverse tests in order to make 8M pages the special case and > other ones (512k and 16k) the alternative. > > [...] Applied to powerpc/next. [1/1] powerpc/8xx: Reduce alignment constraint for kernel memory https://git.kernel.org/powerpc/c/f9cb1476ade41ba859e6f41323e76284b297d7c2 Thanks