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Received: from willy by casper.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1rfsxA-00000009hNq-3THo; Fri, 01 Mar 2024 02:48:52 +0000 Date: Fri, 1 Mar 2024 02:48:52 +0000 From: Matthew Wilcox To: Kent Overstreet Cc: NeilBrown , Amir Goldstein , paulmck@kernel.org, lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org, linux-fsdevel , Jan Kara Subject: Re: [Lsf-pc] [LSF/MM/BPF TOPIC] Reclamation interactions with RCU Message-ID: References: <170925937840.24797.2167230750547152404@noble.neil.brown.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 36B34C000B X-Rspam-User: X-Stat-Signature: 8ks5f1zypejetg8kqu6mk8hb4kz7uz17 X-Rspamd-Server: rspam01 X-HE-Tag: 1709261337-523405 X-HE-Meta: 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 6Nw6RfFf ZzTRuo/kFNIaBDgVUr6wXsEZSCKHmkh/xyN2hl/V/LmQi4+Bm8uXwKc1iikNNkjzEvR2KViSBSwgXkOXwo7T6iydjrC9jfou5UrApG0q66znCZi+i6JMyvAJn5r3JSJRzSd25AM++S3XdXYM= 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, Feb 29, 2024 at 09:39:17PM -0500, Kent Overstreet wrote: > On Fri, Mar 01, 2024 at 01:16:18PM +1100, NeilBrown wrote: > > Insisting that GFP_KERNEL allocations never returned NULL would allow us > > to remove a lot of untested error handling code.... > > If memcg ever gets enabled for all kernel side allocations we might > start seeing failures of GFP_KERNEL allocations. Why would we want that behaviour? A memcg-limited allocation should behave like any other allocation -- block until we've freed some other memory in this cgroup, either by swap or killing or ...