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[173.79.60.52]) by smtp.gmail.com with ESMTPSA id af79cd13be357-93c2485dce4sm250217085a.23.2026.09.23.08.24.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Sep 2026 08:24:27 -0700 (PDT) Date: Wed, 23 Sep 2026 11:24:25 -0400 From: Gregory Price To: "Vlastimil Babka (SUSE)" Cc: Lance Yang , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, akpm@linux-foundation.org, surenb@google.com, mhocko@suse.com, brendan.jackman@linux.dev, hannes@cmpxchg.org, ziy@nvidia.com, david@kernel.org, ljs@kernel.org, liam@infradead.org, rppt@kernel.org, baolin.wang@linux.alibaba.com, nico.pache@linux.dev, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, usama.arif@linux.dev, kas@kernel.org, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, ying.huang@linux.alibaba.com, apopple@nvidia.com Subject: Re: [PATCH] mm/page_alloc: let the bulk and folio allocators carry alloc_flags Message-ID: References: <20260914155115.439742-1-gourry@gourry.net> <20260922130558.48402-1-lance.yang@linux.dev> <80206444-d0c3-4dab-a5e3-a2909e58ea33@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <80206444-d0c3-4dab-a5e3-a2909e58ea33@kernel.org> X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 8AE8680007 X-Stat-Signature: 5dgihj8b5yc7715hjb67iicgtooamuee X-HE-Tag: 1790177069-49124 X-HE-Meta: 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 C0mgBGFw XgeflubISAu7gBI0pDAflYYQBAgTNdMpGkqJOsx6APqEUxqB8sij+huBCl+51WnpyV6JEL67L27/QTZLWmrrENN/4vDe/+PdR+wEi5Ik9K+gxnhsUl2frE70cBHKMqM03IXyAEGVnhC7sX6/5YScqWLJADkTSsCHFasu0BcrKV5qdHkKYrTQN7OuDI2Wgm5Yys/MoIlpPLOpg0hl4LAKn9fqsNrKUKVTvPS0Oom7N1XhRnKmQu0Imc7C3mPTEH4yWyLA9ZFGzLyzkCr2nezmrqar5E36OZgA20yy81Wr15YoAdM5aIjLDER44eQqijpKvMIGwzs02BGPcuFAG96iaKe5AiAwSOycgJxl2EoRT8kHztI1IAsPRz9tZk/NWdhMzdguZwvebDbjJH4FOUXTJ4c5l3XdA641YeQOpAqb2k678nqlEVJWcyxkOctMmLxhwp9Wm Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Sep 23, 2026 at 08:32:29AM +0200, Vlastimil Babka (SUSE) wrote: > On 9/23/26 03:59, Gregory Price wrote: > > On Tue, Sep 22, 2026 at 09:05:58PM +0800, Lance Yang wrote: > > > > There is some concern around NOLOCK here yes, in fact sashiko picked > > this issue up and I've been poking at it. > > It's possible to document it as unsupported, add a VM_WARN_ON_ONCE etc. > It's not necessary for bulk alloc to support ALLOC_NOLOCK just because it > takes flags. e.g. kmalloc_nolock() supports a subset of gfp flags as well. > It seemed simpler to just support it than to create more future footguns. I can RFC my current rework if you like, i attempted to deduplicate the logic via a prepare_alloc_flags() called from both the bulk and non-bulk contexts. But if we prefer the WARNs over adding the new semantics to the bulk allocator, that also doesn't seem unreasonable. ~Gregory