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Wed, 02 Apr 2025 00:59:57 -0700 (PDT) Message-ID: Date: Wed, 2 Apr 2025 15:59:51 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm: page_alloc: Remove redundant READ_ONCE To: Songtang Liu , akpm@linux-foundation.org, ying.huang@linux.alibaba.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, zhengqi.arch@bytedance.com, songmuchun@bytedance.com References: From: Qi Zheng In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 4/2/25 3:41 PM, Songtang Liu wrote: > In the current code, batch is a local variable, and it cannot be > concurrently modified. It's unnecessary to use READ_ONCE here, > so remove it. > > Fixes: 51a755c56dc0 ("mm: tune PCP high automatically") > Signed-off-by: Songtang Liu > --- > mm/page_alloc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index e3ea5bf5c459..6edc6e57d4f8 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -2661,7 +2661,7 @@ static void free_frozen_page_commit(struct zone *zone, > free_high = (pcp->free_count >= batch && > (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER) && > (!(pcp->flags & PCPF_FREE_HIGH_BATCH) || > - pcp->count >= READ_ONCE(batch))); > + pcp->count >= batch)); > pcp->flags |= PCPF_PREV_FREE_HIGH_ORDER; > } else if (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER) { > pcp->flags &= ~PCPF_PREV_FREE_HIGH_ORDER; Reviewed-by: Qi Zheng Thanks!