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b=fv0cpirSgC2/1kbacDMS6s8OqbhfxuEyqpc0Pc3/XXI5/fmVVOR9CQnbHSQLWLPIb tdoc7XSrvD2hb2yP2UCQo2TaisCNG1l73pKyjpJt85tM+cFjuqgREER2G7sEhbMT8q OBh8Wn5AynraPIkFrwDteE2XAPbxUCgXZkdRYuSU= Date: Thu, 27 Jun 2024 14:37:19 -0700 From: Andrew Morton To: Tvrtko Ursulin Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-dev@igalia.com, Tvrtko Ursulin , Huang Ying , Mel Gorman , Peter Zijlstra , Ingo Molnar , Rik van Riel , Johannes Weiner , "Matthew Wilcox (Oracle)" , Dave Hansen , Andi Kleen , Michal Hocko , David Rientjes Subject: Re: [PATCH] mm/numa_balancing: Teach mpol_to_str about the balancing mode Message-Id: <20240627143719.86a92240516e689c2f2d1c09@linux-foundation.org> In-Reply-To: <20240625132605.38428-1-tursulin@igalia.com> References: <20240625132605.38428-1-tursulin@igalia.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: trxc4jwraasun7rqiw1chaosgpbyk9ak X-Rspamd-Queue-Id: 9D491140009 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1719524244-49267 X-HE-Meta: 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 79EyC8ab fv1iqcKZ4iOj8TiRFQE2jISgEvNIgq23dpZuPStodgJz7qurM945FX3Ieghtp/0db/5pn0u/65t1XdqiQvgmhtKfeRzGtKgORVRhd97kyRjhgsa9SH6Yea0hzRRHrN2KOWMgO4NqNbsozxGO/VSKB4CG9Dyve0N5klVmXNi/5OTBZuOHt6qYLLzQiuL7GXw8lGiAoHwYz71GtUgED5K324ALeiOx1O/Qblu8EcAcHY/GXcHxl4/0R9m2m1RkxnivIvOT4vFEWVotaVH4aG3qxBm9xY7Vl37BQOrvi3G2Y7boWD0gYBympb95Yzobw6cJVJPBkygp/yzyP/4c= 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 Tue, 25 Jun 2024 14:26:05 +0100 Tvrtko Ursulin wrote: > From: Tvrtko Ursulin > > If a task has had MPOL_F_NUMA_BALANCING set it is useful to show that in > procfs. Teach the mpol_to_str helper about its existance and while at it > update the comment to account for "weighted interleave" when suggesting > a recommended buffer size. > > ... > > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -3293,8 +3293,9 @@ int mpol_parse_str(char *str, struct mempolicy **mpol) > * @pol: pointer to mempolicy to be formatted > * > * Convert @pol into a string. If @buffer is too short, truncate the string. > - * Recommend a @maxlen of at least 32 for the longest mode, "interleave", the > - * longest flag, "relative", and to display at least a few node ids. > + * Recommend a @maxlen of at least 42 for the longest mode, "weighted > + * interleave", the longest flag, "balancing", and to display at least a few > + * node ids. > */ > void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol) > { > @@ -3331,12 +3332,15 @@ void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol) > p += snprintf(p, buffer + maxlen - p, "="); > > /* > - * Currently, the only defined flags are mutually exclusive > + * The below two flags are mutually exclusive: > */ > if (flags & MPOL_F_STATIC_NODES) > p += snprintf(p, buffer + maxlen - p, "static"); > else if (flags & MPOL_F_RELATIVE_NODES) > p += snprintf(p, buffer + maxlen - p, "relative"); > + > + if (flags & MPOL_F_NUMA_BALANCING) > + p += snprintf(p, buffer + maxlen - p, "balancing"); > } > > if (!nodes_empty(nodes)) Is it strange to report this via mount options? `static' and `relative' can be set via mount options but afaict `balancing' cannot? I guess not... Documentation/filesystems/tmpfs.rst appears to be a suitable place to document this new userspace API please.