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charset=us-ascii Content-Disposition: inline In-Reply-To: <971b9a05-4ae0-4e6c-8e48-e9e529896ecf@arm.com> X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 9880A20007 X-Stat-Signature: 1gmxjjcd3s8zmfstqg556e6gsgk4oorn X-Rspam-User: X-HE-Tag: 1735844292-970932 X-HE-Meta: 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 u4Gpdhgm 64AaJmAGhn2ilV7Ro0kB3g3xwB1m+8x8lxsKIsOZUURzgrOgdXsOHq3huOj51qz55bg2U6sBhzxXSRcSweo1yTVBDof3vtF99KcUOZJfHRiNnzdVyumkf6JroJunFl0G2dcEzV2BqGJ7y3eQd/xNhXwWRecNpEh/f0KI4WcgvXFMgoY2CI4KoHQJRSa2tT6rACUkq7ViNcZy3YSHOcnQaI45o+28sWO0d0hqS0sPEXULsUUS1wrZuk4T7m/BnlyC+LB3uz47PFqLcvo4hKR0Bx5GgAxWqEYbJhwKKBrS76tgs4D1AwPzBnhqlrx2MAtFZewVaaprWgzCx1YgupX8GkJuWm6Sx1RkOjfmo X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Dec 27, 2024 at 01:19:30PM +0530, Anshuman Khandual wrote: > On 12/24/24 19:39, Catalin Marinas wrote: > > On Tue, Dec 24, 2024 at 05:32:06PM +0800, Zhenhua Huang wrote: > >> I have two ideas: > >> 1. Completely disable this PMD mapping optimization since there is no > >> guarantee we must align 128M memory for hotplug .. > > > > I'd be in favour of this, at least if CONFIG_MEMORY_HOTPLUG is enabled. > > I think the only advantage here is that we don't allocate a full 2MB > > block for vmemmap when only plugging in a sub-section. > > Agreed, that will be the right fix for the problem which can be back ported. > We will have to prevent PMD/PUD/CONT mappings for both linear and as well as > vmemmap for all non-boot memory sections, that can be hot-unplugged. I haven't read your diffs below yet but why not allow PMD mappings of the hotplugged memory (not vmemmap)? SUBSECTION_SHIFT is 21, so we can have 2MB blocks in a 4KB page configuration. -- Catalin