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charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20221202115954.a226f8ef3051266d04caff54@linux-foundation.org> X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 9EB8B14000D X-Stat-Signature: pge68ht5csz8u3sujqex41irheczssc5 X-HE-Tag: 1671187594-285987 X-HE-Meta: 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 HTYWzamh j8og7 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 Fri, Dec 02, 2022 at 11:59:54AM -0800, Andrew Morton wrote: > On Fri, 2 Dec 2022 22:16:30 +0800 tzm wrote: > > > It will be failed to disable numa balancing policy permanently by passing > > to boot cmdline parameters. > > The numabalancing_override variable is int and 1 for enable -1 for disable. > > So, !enumabalancing_override will always be true, which cause this bug. > > That's really old code! > > > --- a/mm/mempolicy.c > > +++ b/mm/mempolicy.c > > @@ -2865,7 +2865,7 @@ static void __init check_numabalancing_enable(void) > > if (numabalancing_override) > > set_numabalancing_state(numabalancing_override == 1); > > > > - if (num_online_nodes() > 1 && !numabalancing_override) { > > + if (num_online_nodes() > 1 && (numabalancing_override == 1)) { > > pr_info("%s automatic NUMA balancing. Configure with numa_balancing= or the kernel.numa_balancing sysctl\n", > > numabalancing_default ? "Enabling" : "Disabling"); > > set_numabalancing_state(numabalancing_default); > > Looks right to me. Mel? > > After eight years, I wonder if we actually need this. I don't think the patch is right aside from coding style issues such as real names used in signed-off-by's. The !numabalancing_override is checking "should the default be changed?", itt's not checking if it should be enabled specifically. A better potential fix would be something like this? (not actually tested) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 61aa9aedb728..fc649f8509f7 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2862,10 +2862,12 @@ static void __init check_numabalancing_enable(void) numabalancing_default = true; /* Parsed by setup_numabalancing. override == 1 enables, -1 disables */ - if (numabalancing_override) + if (numabalancing_override) { set_numabalancing_state(numabalancing_override == 1); + return; + } - if (num_online_nodes() > 1 && !numabalancing_override) { + if (num_online_nodes() > 1) { pr_info("%s automatic NUMA balancing. Configure with numa_balancing= or the kernel.numa_balancing sysctl\n", numabalancing_default ? "Enabling" : "Disabling"); set_numabalancing_state(numabalancing_default);