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Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pefdm-002E2a-1j; Tue, 21 Mar 2023 17:19:18 +0000 Date: Tue, 21 Mar 2023 17:19:18 +0000 From: Matthew Wilcox To: Luis Chamberlain Cc: Yangtao Li , Alexander Viro , Christian Brauner , Andrew Morton , Kees Cook , Iurii Zaikin , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] fs/drop_caches: move drop_caches sysctls into its own file Message-ID: References: <20230321130908.6972-1-frank.li@vivo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: B7ABC180004 X-Stat-Signature: tkw6qkda7e98akn5g9cmoq3xfqa8r8ro X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1679419168-540066 X-HE-Meta: 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 dFUjKRjd 70Fl/quh/PgwPuKjYIYfAf4rB3ofYVgl002g0hOp8758Am+qq0CVNhYOzlJBvNxiB4P/W4oNKdGm86Vk8RecnqKlULyHgP5smXDAEHvJEGHZxOyN2oIkjAr5a598tHhOkjvQX40SSa/b7E250QKBNe20saZppbl34yxnqHha9vSqKdHkMsuxllTRNEIJWPfBYwhB8XZvNE9049zY= 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: On Tue, Mar 21, 2023 at 09:56:03AM -0700, Luis Chamberlain wrote: > On Tue, Mar 21, 2023 at 04:42:32PM +0000, Matthew Wilcox wrote: > > On Tue, Mar 21, 2023 at 09:09:07PM +0800, Yangtao Li wrote: > > > +static struct ctl_table drop_caches_table[] = { > > > + { > > > + .procname = "drop_caches", > > > + .data = &sysctl_drop_caches, > > > + .maxlen = sizeof(int), > > > + .mode = 0200, > > > + .proc_handler = drop_caches_sysctl_handler, > > > + .extra1 = SYSCTL_ONE, > > > + .extra2 = SYSCTL_FOUR, > > > + }, > > > + {} > > > +}; > > > > Could we avoid doing this until we no longer need an entire zero entry > > after the last one? > > That may be 2-3 kernel release from now. The way to use ARRAY_SIZE() > really is to deprecate the crap APIs that allow messy directory sysctl > structures. I'm OK with waiting another year to commence this cleanup. We've lived with the giant tables for decades already. Better to get the new API right than split the tables now, then have to touch all the places again.