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([110.9.142.4]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2b5faa17632sm77625145ad.24.2026.04.19.07.42.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 19 Apr 2026 07:42:35 -0700 (PDT) From: Sang-Heon Jeon To: akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com Cc: linux-mm@kvack.org, Sang-Heon Jeon Subject: [PATCH] mm/sparse: remove unnecessary NULL check before allocating mem_section Date: Sun, 19 Apr 2026 23:42:25 +0900 Message-ID: <20260419144225.2875654-1-ekffu200098@gmail.com> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 8F7F714000E X-Rspamd-Server: rspam07 X-Stat-Signature: np6deypg1urxphr8d4nuw4tteqipud8w X-Rspam-User: X-HE-Tag: 1776609757-159097 X-HE-Meta: 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 KZIvgOoo 1oVvYcrlcvJxlLgKTW8vZcXD8WrTEZRnVLQHuiHoIREE96RilUA13+W0D5Th4Qtq+VMC0jLXbbVtwuGO1aZgrU7Q6K7GFSGyNlHRU9fVNfj9Ycbss7TVWHQUlZ2HizX5NWRWNpwYUUjAC1Du/pDKjcpa5QeyuvKF4TDTMzOPv1SENVDGuBUCH2VTC/b2UCGUc5e4Qhxyur/xrsaTjYgUPZ0gTLsKPYSFCbKilMoVMoXnH7jxtf+PCsXuWz+DknnBYO6PHlbKTKa7b0th7iiOEDIn0PXgHqS8LQPdB944HXSu6C6o7lgJPQgOfw8OjoytM9etWlkR7RxlURlIuZZBr4To28BArseW85+f6/lxxUA+NHYbkKH0PhAkni0hMDLn9vgFRCHUWefX6DfvNcz/dvC2OV1qKH280EX58JkNRyB9wAew94ZO5dpKMaZDt99URhf8OAe6KmkDiElQ= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Commit 850ed20539a4 ("mm: move array mem_section init code out of memory_present()") moved mem_section allocation logic into memblocks_present(). Before that move, memory_present() could be called multiple times, so unlikely() matched the common case, where most calls found mem_section already allocated. After that move, memblocks_present() is called exactly once from sparse_init(). Under CONFIG_SPARSEMEM_EXTREME, mem_section is always NULL when it is called. So remove unnecessary NULL check before allocating mem_section. No functional change. Signed-off-by: Sang-Heon Jeon --- Hello, While looking into boot information, I found a minor enhancement point. If I misunderstood anything, please feel free to let me know. Thank you for taking valuable time to review this work. Best Regards, Sang-Heon Jeon --- mm/sparse.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/mm/sparse.c b/mm/sparse.c index effdac6b0ab1..e13f9f5fa090 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -201,13 +201,11 @@ static void __init memblocks_present(void) int i, nid; #ifdef CONFIG_SPARSEMEM_EXTREME - if (unlikely(!mem_section)) { - unsigned long size, align; + unsigned long size, align; - size = sizeof(struct mem_section *) * NR_SECTION_ROOTS; - align = 1 << (INTERNODE_CACHE_SHIFT); - mem_section = memblock_alloc_or_panic(size, align); - } + size = sizeof(struct mem_section *) * NR_SECTION_ROOTS; + align = 1 << (INTERNODE_CACHE_SHIFT); + mem_section = memblock_alloc_or_panic(size, align); #endif for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) -- 2.43.0