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Hallyn" , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-bcachefs@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Michal Hocko Subject: Re: [PATCH 1/2] bcachefs: do not use PF_MEMALLOC_NORECLAIM Message-ID: References: <20240826085347.1152675-1-mhocko@kernel.org> <20240826085347.1152675-2-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Queue-Id: 4F2A018000B X-Rspamd-Server: rspam01 X-Stat-Signature: sufoofzz1ez7shczy5b3u1wuqcm8joo3 X-HE-Tag: 1724701307-215169 X-HE-Meta: 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 tnuvamcD qBaGA35wGJiOte5gNDqIq6Q6/eCXjF5eDVdi8JtVgpZ+xwge/Wf8QK7JvzzRlFgeGUHVIAvXPmtoQDulLgsqpHVUuihnwAcMmz+8f54M8i3baKmEOSmcZMz70EQnlZ7khILN0mDNIpy7EnGIxp9AUUEUoxVd7ypaF5xrsZA0KSuBhm+GB4bheTEqmXEPy+puROJsUHXgoarhbdtssQilpFC0zENV4LjEXrKn+CtI8Oc91qrBRKH34pehs1ClBFvXCodFIYRX7fzlEC4RknCelvw8i3WgzKwBrtqyXh4tPZqxdc4VDhyuNaENaXRM/wsEh3mgf/HOEsVPCCSg= 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 Mon, Aug 26, 2024 at 03:39:47PM -0400, Kent Overstreet wrote: > Given the amount of plumbing required here, it's clear that passing gfp > flags is the less safe way of doing it, and this really does belong in > the allocation context. > > Failure to pass gfp flags correctly (which we know is something that > happens today, e.g. vmalloc -> pte allocation) means you're introducing > a deadlock. The problem with vmalloc is that the page table allocation _doesn't_ take a GFP parameter.