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Wed, 3 Apr 2024 07:25:34 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap2.dmz-prg2.suse.org with ESMTPSA id lsojBW4EDWYGFwAAn2gu4w (envelope-from ); Wed, 03 Apr 2024 07:25:34 +0000 Message-ID: <2cab01ce-7c5f-46d6-b8a4-c2a24c3f9a32@suse.cz> Date: Wed, 3 Apr 2024 09:25:33 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 3/4] mm/slub: simplify get_partial_node() To: "Song, Xiongwei" , "rientjes@google.com" , "cl@linux.com" , "penberg@kernel.org" , "iamjoonsoo.kim@lge.com" , "akpm@linux-foundation.org" , "roman.gushchin@linux.dev" , "42.hyeyoo@gmail.com" <42.hyeyoo@gmail.com> Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "chengming.zhou@linux.dev" References: <20240331021926.2732572-1-xiongwei.song@windriver.com> <20240331021926.2732572-4-xiongwei.song@windriver.com> <69089796-9a3b-41a1-9b7c-18c773b96aa2@suse.cz> Content-Language: en-US From: Vlastimil Babka In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Action: no action X-Spamd-Bar: / X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: E17A180011 X-Stat-Signature: 1jkhoz17dd35ebtapzitqon4sg5rw1dr X-HE-Tag: 1712129135-354524 X-HE-Meta: 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 Ml3jD5V/ A1VSSWNfx3hH/1m+5RBZpHfj9ZnHuUcYt0lXS0HLsZ/Z4BaUQrL3qUk7MCRSkbKkE3d2EjlGRtbFR8/B8uJ1tAejZMfm5XkjQ381aLLSTzrZRrj3KtFgHkxzvrmwLRgj0FYHOK2JFjR5er+HSNhOlbz3g9TF2leMOMY4z9PwJ56P2KBR9UiqxwhT41rUPME2uAVbprvX4uK2gIFQSwk52FggI1b9Zhe8D746eO1pRDgvB74x2+Jwl2kJ33PzkAOHZx5Ksk34KIt38W2V8BevEm6R4o+qk0RwRCGQhmBHAgi+MMRG6JG3UPxOTNhTb4EvMdgY7XHI6fnufonZ+kSuRHJ6G3PT7i0q0HoRksWMndum65jcQtH+zjW0q4Ew5X5dlTgdo8yiO1JMwn8+0w3DzOjrDzOkn6uMyGIlMDUDafAmr998= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000006, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/3/24 2:37 AM, Song, Xiongwei wrote: >> >> >> It could be tempting to use >= instead of > to achieve the same effect but >> that would have unintended performance effects that would best be evaluated >> separately. > > I can run a test to measure Amean changes. But in terms of x86 assembly, there > should not be extra instructions with ">=". > > Did a simple test, for ">=" it uses "jle" instruction, while "jl" instruction is used for ">". > No more instructions involved. So there should not be performance effects on x86. Right, I didn't mean the code of the test, but how the difference of the comparison affects how many cpu partial slabs would be put on the cpu partial list here. > Thanks, > Xiongwei > >> >> > >> > + put_cpu_partial(s, slab, 0); >> > + stat(s, CPU_PARTIAL_NODE); >> > + partial_slabs++; >> > + >> > + if (partial_slabs > slub_get_cpu_partial(s) / 2) >> > + break; >> > } >> > spin_unlock_irqrestore(&n->list_lock, flags); >> > return partial; >