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Sun, 23 Nov 2025 13:58:35 -0500 X-MC-Unique: PsLgnA6uOli0lSIaSWPAWQ-1 X-Mimecast-MFC-AGG-ID: PsLgnA6uOli0lSIaSWPAWQ_1763924314 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 17B8B180057A; Sun, 23 Nov 2025 18:58:34 +0000 (UTC) Received: from fedora (unknown [10.44.32.8]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 048881956056; Sun, 23 Nov 2025 18:58:31 +0000 (UTC) Received: by fedora (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Sun, 23 Nov 2025 19:58:33 +0100 (CET) Date: Sun, 23 Nov 2025 19:58:30 +0100 From: Oleg Nesterov To: Mateusz Guzik Cc: brauner@kernel.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org Subject: Re: [PATCH 2/3] ns: pad refcount Message-ID: References: <20251123063054.3502938-1-mjguzik@gmail.com> <20251123063054.3502938-3-mjguzik@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251123063054.3502938-3-mjguzik@gmail.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: A1026A0004 X-Stat-Signature: rcoxj9te3jtckeag1syo3ky1zenm6wwf X-Rspam-User: X-HE-Tag: 1763924319-441394 X-HE-Meta: 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 uwWhSPkb XPc1VEhKMlO7jvTa0KFZzbOTzth42wtDqYoYb8ScTyEgyARAi1nDW5YY5JwF3RD+ielYVEIKYu18/5otlDVts1KUIGk2xQ2wHxC58te7//FbnLcNfz5+dpbrFuxFjHqsVKueFeNhI53lPgKm2rYfP4kbkX0FX3fXx+xfJBnsaCcrG/S1hmlNaCzLmZAao+TISr5iqsI8OGGl6tI3HNLKeqCtZOcXVqy3mxaMZ8GyJ7ccjNozTIacIU/Q5VdGM0bwb7/hn8RSYTNzFGio0XvsbC8zS6IMOHknIByw9P56PwSNl/IeQZ4kJoi5yHSCWWjBsYStAxzBYQwfIrdAZ1tXhiP0z0eD3kQ2hLDu8 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 11/23, Mateusz Guzik wrote: > > struct ns_common { > + struct { > + refcount_t __ns_ref; /* do not use directly */ > + } ____cacheline_aligned_in_smp; Cough... stupid question. Why not just refcount_t __ns_ref ____cacheline_aligned_in_smp; ? why do we need the anonymous struct? Oleg.