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Thu, 27 Nov 2025 23:36:52 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id zCs2OpTgKGlAGQAAD6G6ig (envelope-from ); Thu, 27 Nov 2025 23:36:52 +0000 From: Gabriel Krisman Bertazi To: linux-mm@kvack.org Cc: Gabriel Krisman Bertazi , linux-kernel@vger.kernel.org, jack@suse.cz, Mateusz Guzik , Shakeel Butt , Michal Hocko , Mathieu Desnoyers , Dennis Zhou , Tejun Heo , Christoph Lameter , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan Subject: [RFC PATCH 1/4] lib/percpu_counter: Split out a helper to insert into hotplug list Date: Thu, 27 Nov 2025 18:36:28 -0500 Message-ID: <20251127233635.4170047-2-krisman@suse.de> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251127233635.4170047-1-krisman@suse.de> References: <20251127233635.4170047-1-krisman@suse.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; MID_CONTAINS_FROM(1.00)[]; R_MISSING_CHARSET(0.50)[]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; FUZZY_RATELIMITED(0.00)[rspamd.com]; RCPT_COUNT_TWELVE(0.00)[18]; MIME_TRACE(0.00)[0:+]; RCVD_TLS_ALL(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; URIBL_BLOCKED(0.00)[imap1.dmz-prg2.suse.org:helo,suse.de:mid,suse.de:email]; FROM_HAS_DN(0.00)[]; FREEMAIL_CC(0.00)[suse.de,vger.kernel.org,suse.cz,gmail.com,linux.dev,kernel.org,efficios.com,gentwo.org,linux-foundation.org,redhat.com,oracle.com,google.com]; TO_DN_SOME(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FREEMAIL_ENVRCPT(0.00)[gmail.com] X-Spam-Level: X-Spam-Score: -2.80 X-Spam-Flag: NO Content-Type: text/plain; charset="utf-8" In preparation to using it with the lazy pcpu counter. Signed-off-by: Gabriel Krisman Bertazi --- lib/percpu_counter.c | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-) diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c index 2891f94a11c6..c2322d53f3b1 100644 --- a/lib/percpu_counter.c +++ b/lib/percpu_counter.c @@ -185,11 +185,26 @@ s64 __percpu_counter_sum(struct percpu_counter *fbc) } EXPORT_SYMBOL(__percpu_counter_sum); =20 +static int cpu_hotplug_add_watchlist(struct percpu_counter *fbc, int nr_co= unters) +{ +#ifdef CONFIG_HOTPLUG_CPU + unsigned long flags; + int i; + + spin_lock_irqsave(&percpu_counters_lock, flags); + for (i =3D 0; i < nr_counters; i++) { + INIT_LIST_HEAD(&fbc[i].list); + list_add(&fbc[i].list, &percpu_counters); + } + spin_unlock_irqrestore(&percpu_counters_lock, flags); +#endif + return 0; +} + int __percpu_counter_init_many(struct percpu_counter *fbc, s64 amount, gfp_t gfp, u32 nr_counters, struct lock_class_key *key) { - unsigned long flags __maybe_unused; size_t counter_size; s32 __percpu *counters; u32 i; @@ -205,21 +220,12 @@ int __percpu_counter_init_many(struct percpu_counter = *fbc, s64 amount, for (i =3D 0; i < nr_counters; i++) { raw_spin_lock_init(&fbc[i].lock); lockdep_set_class(&fbc[i].lock, key); -#ifdef CONFIG_HOTPLUG_CPU - INIT_LIST_HEAD(&fbc[i].list); -#endif fbc[i].count =3D amount; fbc[i].counters =3D (void __percpu *)counters + i * counter_size; =20 debug_percpu_counter_activate(&fbc[i]); } - -#ifdef CONFIG_HOTPLUG_CPU - spin_lock_irqsave(&percpu_counters_lock, flags); - for (i =3D 0; i < nr_counters; i++) - list_add(&fbc[i].list, &percpu_counters); - spin_unlock_irqrestore(&percpu_counters_lock, flags); -#endif + cpu_hotplug_add_watchlist(fbc, nr_counters); return 0; } EXPORT_SYMBOL(__percpu_counter_init_many); --=20 2.51.0