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[109.81.91.122]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49cf771e9absm62865535e9.9.2026.09.04.04.05.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Sep 2026 04:05:02 -0700 (PDT) Date: Fri, 4 Sep 2026 13:05:00 +0200 From: Michal Hocko To: Ye Liu Cc: Miaohe Lin , Andrew Morton , Ye Liu , Naoya Horiguchi , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/8] mm/memory-failure: convert process iterator to for_each_process_rcu Message-ID: References: <20260904083001.553587-1-ye.liu@linux.dev> <20260904083001.553587-5-ye.liu@linux.dev> 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: <20260904083001.553587-5-ye.liu@linux.dev> On Fri 04-09-26 16:29:56, Ye Liu wrote: > From: Ye Liu > > Replace the manual rcu_read_lock()/rcu_read_unlock() pairs combined > with for_each_process() loop in mm/memory-failure.c with > for_each_process_rcu(). > > No functional change. > > Signed-off-by: Ye Liu Acked-by: Michal Hocko > --- > mm/memory-failure.c | 16 ++++------------ > 1 file changed, 4 insertions(+), 12 deletions(-) > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index a8b03e2920ba..63a2ff08ee33 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -555,8 +555,7 @@ static void collect_procs_anon(const struct folio *folio, > return; > > pgoff = page_pgoff(folio, page); > - rcu_read_lock(); > - for_each_process(tsk) { > + for_each_process_rcu(tsk) { > struct vm_area_struct *vma; > struct anon_vma_chain *vmac; > struct task_struct *t = task_early_kill(tsk, force_early); > @@ -572,7 +571,6 @@ static void collect_procs_anon(const struct folio *folio, > add_to_kill_anon_file(t, page, vma, to_kill, addr); > } > } > - rcu_read_unlock(); > anon_vma_unlock_read(av); > } > > @@ -589,9 +587,8 @@ static void collect_procs_file(const struct folio *folio, > pgoff_t pgoff; > > i_mmap_lock_read(mapping); > - rcu_read_lock(); > pgoff = page_pgoff(folio, page); > - for_each_process(tsk) { > + for_each_process_rcu(tsk) { > struct task_struct *t = task_early_kill(tsk, force_early); > unsigned long addr; > > @@ -611,7 +608,6 @@ static void collect_procs_file(const struct folio *folio, > add_to_kill_anon_file(t, page, vma, to_kill, addr); > } > } > - rcu_read_unlock(); > i_mmap_unlock_read(mapping); > } > > @@ -635,8 +631,7 @@ static void collect_procs_fsdax(const struct page *page, > struct task_struct *tsk; > > i_mmap_lock_read(mapping); > - rcu_read_lock(); > - for_each_process(tsk) { > + for_each_process_rcu(tsk) { > struct task_struct *t = tsk; > > /* > @@ -653,7 +648,6 @@ static void collect_procs_fsdax(const struct page *page, > add_to_kill_fsdax(t, page, vma, to_kill, pgoff); > } > } > - rcu_read_unlock(); > i_mmap_unlock_read(mapping); > } > #endif /* CONFIG_FS_DAX */ > @@ -2288,8 +2282,7 @@ static void collect_procs_pfn(struct pfn_address_space *pfn_space, > struct address_space *mapping = pfn_space->mapping; > > i_mmap_lock_read(mapping); > - rcu_read_lock(); > - for_each_process(tsk) { > + for_each_process_rcu(tsk) { > struct task_struct *t = tsk; > > t = task_early_kill(tsk, true); > @@ -2303,7 +2296,6 @@ static void collect_procs_pfn(struct pfn_address_space *pfn_space, > add_to_kill_pgoff(t, vma, to_kill, pgoff); > } > } > - rcu_read_unlock(); > i_mmap_unlock_read(mapping); > } > > -- > 2.25.1 > -- Michal Hocko SUSE Labs