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[100.36.248.188]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-8c90b2dc4besm54238296d6.32.2026.05.15.08.52.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 May 2026 08:52:02 -0700 (PDT) Date: Fri, 15 May 2026 11:52:00 -0400 From: Gregory Price To: Brendan Jackman Cc: "Vlastimil Babka (SUSE)" , Borislav Petkov , Dave Hansen , Peter Zijlstra , Andrew Morton , David Hildenbrand , Wei Xu , Johannes Weiner , Zi Yan , Lorenzo Stoakes , linux-mm@kvack.org, linux-kernel@vger.kernel.org, x86@kernel.org, rppt@kernel.org, Sumit Garg , derkling@google.com, reijiw@google.com, Will Deacon , rientjes@google.com, "Kalyazin, Nikita" , patrick.roy@linux.dev, "Itazuri, Takahiro" , Andy Lutomirski , David Kaplan , Thomas Gleixner , Yosry Ahmed Subject: Re: [PATCH v2 18/22] mm/page_alloc: introduce ALLOC_NOBLOCK Message-ID: References: <20260320-page_alloc-unmapped-v2-0-28bf1bd54f41@google.com> <20260320-page_alloc-unmapped-v2-18-28bf1bd54f41@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: A36F52000F X-Stat-Signature: gjzu73dr9d6adcjk8oety84f8mo74bsg X-Rspam-User: X-HE-Tag: 1778860323-235967 X-HE-Meta: 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 scGcSsRU w18qsK7qI/BK4J/M72eigHlDpAbk2znztExBAD4fHzqnAzfe7Xq/f9xgkETVQ8tWtgU5jnmU5xWhfB7EqQUwsXynxXBGDZcIpjUf3e3WhgfQS9Ad2D0/vtKW7yIPvWRiFjuEUtHqpa5+U8UZ6Lq8Kx0m5LMwWIgoL3iMVki9WM+Ma5PuLIgEfGfqX74EHEepSXiqAa9ysTwF/1pwrzvfz47s8ngrIQ0HrHtfaeW5DPM4ASjDCt6mO5TKCfWV2PQ3LgGoZ5ToKacG8XmnQok+fwDWYAGIJ27U3duWMc8EA0eD76V8WXvJfljju8K9Y+YWxCIUGJwJt3oZHSVi1Cyq+Na3srF8ZralECb/ytlyLUCqLNy8HyhDwD76imw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, May 15, 2026 at 01:36:43PM +0000, Brendan Jackman wrote: > On Wed May 13, 2026 at 9:43 AM UTC, Vlastimil Babka (SUSE) wrote: > > > > Is it safe to just combine them? You come with ALLOC_WMARK_LOW and combine > > with ALLOC_WMARK_MIN from gfp_to_alloc_flags() but these are not bit flags, > > I think you end up with ALLOC_WMARK_LOW effectively. > > Ah, thanks, I do remember thinking about this and deciding that it was > safe but I probably just misunderstood the watermark code. > > This makes me a bit more attracted to the idea of a struct like Gregory > suggested in [1]. Then this could be captured in the type system. > This might actually be a good precursor before pulling alloc_context any further out. Since there's multiple paths into the lower layers with alloc_context, maybe there should already be a sanity check of the alloc flags anyway. ~Gregory