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h=Date:From:To:Cc:Subject:References:In-Reply-To; b=MwavFRK/ztSyhXEhkjmbGgqiZw9sxr6mV1TbmhsRFf12TB/TYGglIbkUGeV7tUtxg F148rzwylaMteqXTQlfgqCpYKWA3xLRuiSk/6ZuEdUVkyxHT5HaPDlNP0bbVm6Mp4p FjSWVQUHDyaswMIHtvx1lOd10oe48Ss+ENBMUdnmWGrLP856Z/MdRVE992y9WKpPde +MjO72CMnbl+RMjRI6UWUrE7V/VLv19l77g/zVYAe07/V28dqEfQXF1MRWhBgAn38K WdW1TZooWTeccR2yS/OgrcO2v9FkbaEz0BGcv51hlHvuCPSmslvFgE1NzbkgrltoCJ qqFQ5EJFaso2A== Date: Tue, 8 Sep 2026 13:17:50 +0300 From: Mike Rapoport To: Thierry Reding Cc: Vincent Donnefort , catalin.marinas@arm.com, will@kernel.org, akpm@linux-foundation.org, sudeep.holla@kernel.org, jenswi@kernel.org, robh@kernel.org, mark.rutland@arm.com, sumit.garg@kernel.org, ardb@kernel.org, david@kernel.org, danielmentz@google.com, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, op-tee@lists.trustedfirmware.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v9 01/10] memblock: Introduce MEMBLOCK_LLMAP Message-ID: References: <20260902104712.2399797-1-vdonnefort@google.com> <20260902104712.2399797-2-vdonnefort@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: DAB861C000A X-Stat-Signature: fatpadcn6pfbpsd4qy9icmwkk8hu1bb5 X-HE-Tag: 1788862680-506031 X-HE-Meta: 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 jhi6peHW 4GcIh2A57DF6lFPi+KD098CX2RbGR0jFnHFhU7VnYo0dd5C7XqnIz+BBgwJDIRiqqetXxXEX5rMlLROQFWpF69VpSipRcsVWb4lf2Jp9ZiG2ROMkESgZvSKR+qtorwJ2V/DepzO6mcjqMTNa/h6ngMGIsvUbCjIebOQbPm6N637g2z90efZkkprfhxQFMh1zlHviLw+bGtYbzrbYTES9aig60PfoGbF+y9so5YH5jPwnKBGXFxurzoeAimfhv8CPh+ANBKy7njucvGpbRHAH5Rg1zApT/rxDLLoE+KO00Q8hvlmA= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Sep 08, 2026 at 11:18:53AM +0200, Thierry Reding wrote: > On Tue, Sep 08, 2026 at 10:40:16AM +0300, Mike Rapoport wrote: > > On Mon, Sep 07, 2026 at 10:50:12AM +0100, Vincent Donnefort wrote: > > > On Sun, Sep 06, 2026 at 10:33:11PM +0300, Mike Rapoport wrote: > > > > On Wed, Sep 02, 2026 at 11:47:03AM +0100, Vincent Donnefort wrote: > > > > > Keeping last-level mappings is interesting on some architectures as it > > > > > allows mapping/unmapping pages from the kernel direct map without the > > > > > risk of splitting blocks which, under the break-before-make rule, may > > > > > trigger page-faults the kernel can't handle. > > > > > > > > > > However, mapping the entire direct map at PTE-level is costly. So > > > > > instead, create a new memblock flag MEMBLOCK_LLMAP to enable the system > > > > > > > > I believe MEMBLOCK_PTE_MAP sounds more descriptive. > > > > > > The idea was to have something close from NOMAP, to emphasis it is one or the > > > other. But PTE_MAP sounds good too. > > > > Could be PTEMAP if you prefer. > > My point was that unlike PTE, "LL" is not perceived as last-level, it > > should be looked up. > > We were discussing the concept of enabling entire block mappings to be > removed at once from the linear map, so at that point "PTE"MAP may no > longer be accurate. > > I imagine that in some scenarios we might be able to go to PUD mappings > for something like VPR (say systems with a fair amount of system memory > and we want to carve out 4 GiB for VPR, split into four 1 GiB chunks). _LEAFMAP then? ;-) > Thierry -- Sincerely yours, Mike.