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b=Vhz9MLtWWmXiJyfJszBrF18JGNnetf7ZJj0t4W6UqAPasYEGuGGb1NPN4GCrtPTkU CD9VK/B27CWo34P8LE7C1z7citVmlQ/6bnZ21c/+i9isgm1MEDJNID4bFFuu9BqDgt 9mau9Yu+u9jF8BZhNbYsX6AUS7HR6A7YPlEKGKMQlcL1uIZTXnwbJEpW3O9g2tOs0N s9NFsrNx7ObhjcXPghnotyVevIp9XnlJULFAYVa4LmAK1ESsPJUBhBb1UC6pGqBWea 7iniKU7Dr0kzIlv5EIx3PsjrMuHNb2lc2t5jS8ocYzbL5idf4UrK9bIJErvamLFxN1 0Yk5Zf1hBBKMw== Date: Thu, 18 Apr 2024 21:03:13 +0300 From: Mike Rapoport To: DaeRo Lee Cc: robh@kernel.org, saravanak@google.com, akpm@linux-foundation.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Daero Lee Subject: Re: [PATCH v2] memblock: add no-map alloc functions Message-ID: References: <20240416120635.361838-1-skseofh@gmail.com> <20240416120635.361838-2-skseofh@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Stat-Signature: mjpbq8iuxzmunbks7tqtn3o91qfri9oy X-Rspamd-Queue-Id: 450B340019 X-Rspamd-Server: rspam06 X-Rspam-User: X-HE-Tag: 1713463466-135920 X-HE-Meta: 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 OEZ3uSpr OkvGTQQn7sXpR35LOrZ2xTZ50kUpC4pfdfqwn5nwWP4NYMZplra58dM1YtcFQe5IlZ6E1e+aHAcrK2GLvCJxoPX9ztHOl4A6JRvVNr0kys4kH+SBpmpl7TmcrTEyX7tKDFgoNP5cAkaj9bq6SaBSdAZwGLnWGyQfh7Hw7FrUY7rX4KWl6tnLJjx62/gNMMKVEm5OPWXNyEunHlFebcKE6h06ChxDMToNcaWlmSm6aWH6zwJsti9X1NdQgWrGv5LQ18YcoRo1S+Sp+WFf+wa77TRH1xGv/U/8zs0vhOt417mh+OapVl3+EaqWpLcnouSa43x1c 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 Thu, Apr 18, 2024 at 11:54:15PM +0900, DaeRo Lee wrote: > 2024년 4월 17일 (수) 오후 3:03, Mike Rapoport 님이 작성: > > > > On Tue, Apr 16, 2024 at 09:06:35PM +0900, skseofh@gmail.com wrote: > > > From: Daero Lee > > > > > > Like reserved-memory with the 'no-map' property and only 'size' property > > > (w/o 'reg' property), there are memory regions need to be allocated in > > > memblock.memory marked with the MEMBLOCK_NOMAP flag, but should not be > > > allocated in memblock.reserved. > > > > This still does not explain why you need such regions. > > > > As Wei Yang explained, memblock does not allocate memory from > > memblock.reserved. The memblock.reserved array represents memory that is in > > use by firmware or by early kernel allocations and cannot be freed to page > > allocator. > Thank you for your comments. I used the wrong word. > When I use 'allocate', I mean that the region 'adds' to the memblock.reserved. > > > > > If you have a region that's _NOMAP in memblock.memory and is absent in > > memblock.reserved it will not be mapped by the kernel page tables, but it > > will be considered as free memory by the core mm. > > > > Is this really what you want? > If my understanding is right, before freeing (memory && !reserved) > area, we marked the memblock.reserved regions and memblock.memory > regions with no-map flag. And when we free (memory && !reserved) area, > we skip the memblock.memory regions with no-map(see > should_skip_region). So, I think that the memory regions with no-map > flag will not be considered as free memory. You are right here. But I still don't understand *why* do you want to change the way early_init_dt_alloc_reserved_memory_arch() works. > Regards, > DaeRo Lee -- Sincerely yours, Mike.