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Thu, 05 Mar 2026 05:09:16 -0800 (PST) Date: Thu, 5 Mar 2026 08:09:15 -0500 From: Johannes Weiner To: "Vlastimil Babka (SUSE)" Cc: Andrew Morton , Hao Li , Michal Hocko , Roman Gushchin , Shakeel Butt , Vlastimil Babka , Harry Yoo , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Johannes Weiner Subject: Re: [PATCH 1/5] mm: memcg: factor out trylock_stock() and unlock_stock() Message-ID: References: <20260302195305.620713-1-hannes@cmpxchg.org> <20260302195305.620713-2-hannes@cmpxchg.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Mar 03, 2026 at 10:23:54AM +0100, Vlastimil Babka (SUSE) wrote: > On 3/2/26 20:50, Johannes Weiner wrote: > > From: Johannes Weiner > > > > Consolidate the local lock acquisition and the local stock > > lookup. This allows subsequent patches to use !!stock as an easy way > > to disambiguate the locked vs. contended cases through the callstack. > > > > Signed-off-by: Johannes Weiner > > Reviewed-by: Vlastimil Babka (SUSE) Thanks! > nit: > > > --- > > mm/memcontrol.c | 25 +++++++++++++++++++------ > > 1 file changed, 19 insertions(+), 6 deletions(-) > > > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > index 753d76e96cc6..a975ab3aee10 100644 > > --- a/mm/memcontrol.c > > +++ b/mm/memcontrol.c > > @@ -3208,6 +3208,19 @@ void __memcg_kmem_uncharge_page(struct page *page, int order) > > obj_cgroup_put(objcg); > > } > > > > +static struct obj_stock_pcp *trylock_stock(void) > > +{ > > + if (local_trylock(&obj_stock.lock)) > > + return this_cpu_ptr(&obj_stock); > > + > > + return NULL; > > +} > > + > > +static void unlock_stock(struct obj_stock_pcp *stock) > > +{ > > + local_unlock(&obj_stock.lock); > > +} > > Could have added inline's there. The compiler heuristics can be sometimes > unpredictable. Oops, I almost missed that, but that sounds good to me. Andrew, would you mind folding this in? diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 36612175e98e..178be98f2e49 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3160,7 +3160,7 @@ void __memcg_kmem_uncharge_page(struct page *page, int order) obj_cgroup_put(objcg); } -static struct obj_stock_pcp *trylock_stock(void) +static inline struct obj_stock_pcp *trylock_stock(void) { if (local_trylock(&obj_stock.lock)) return this_cpu_ptr(&obj_stock); @@ -3168,7 +3168,7 @@ static struct obj_stock_pcp *trylock_stock(void) return NULL; } -static void unlock_stock(struct obj_stock_pcp *stock) +static inline void unlock_stock(struct obj_stock_pcp *stock) { if (stock) local_unlock(&obj_stock.lock);