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[209.85.220.65]) by mx.google.com with SMTPS id m20sor33220461ejk.32.2019.08.08.07.33.38 for (Google Transport Security); Thu, 08 Aug 2019 07:33:38 -0700 (PDT) Received-SPF: pass (google.com: domain of richard.weiyang@gmail.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=cCOBoICU; spf=pass (google.com: domain of richard.weiyang@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=richard.weiyang@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:reply-to:references:mime-version :content-disposition:in-reply-to:user-agent; bh=1+hRXOJC+ZDM/4/kVVufU5PRo9dpiWo2Z8YGtmpPW2I=; b=cCOBoICU8CNt81EgZopFsi62bJmq0dCGhRRyOBZrHz6x4zgZMVW0I0qIH4tqKn99Ch KCuglEQChTF0oNH1RULG7gBFl9ROMSdkWPvDjWYgtyOrwC7lBeww1a4RHafAsavxSbuz Fm5M+8QkjJbkTLchwoDqDiNyYbvLWr++v5jvUHZn519FGt5V8pAxBJ4xQpWhD/gIuloD XKVlh5ov7P2gm1HzEQ48jtXVuZeHjUX32eyJr6Bqts2hiTE9KbIsnJiV+CpxXmKThH2e wmRBJg1RkKYjzuvNjK7zAtt1JAO3piFKSeZxcWyHrAMwdAXPw6YlB+ETRwL/ZUXfkWia 2s4Q== X-Google-Smtp-Source: APXvYqw60Qv6BR5nyiLLGJOB6JFXkK8yFSkjUH6a9VxpLPc86WgYOyY4BHMmwi1P9oj0mhGac7YRMA== X-Received: by 2002:a17:906:4354:: with SMTP id z20mr13315954ejm.163.1565274817932; Thu, 08 Aug 2019 07:33:37 -0700 (PDT) Received: from localhost ([185.92.221.13]) by smtp.gmail.com with ESMTPSA id m17sm255658ejc.91.2019.08.08.07.33.37 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 08 Aug 2019 07:33:37 -0700 (PDT) Date: Thu, 8 Aug 2019 14:33:36 +0000 From: Wei Yang To: Vlastimil Babka Cc: Wei Yang , Michal Hocko , akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/mmap.c: refine data locality of find_vma_prev Message-ID: <20190808143336.kgq4f6j5gfixtcb4@master> Reply-To: Wei Yang References: <20190806081123.22334-1-richardw.yang@linux.intel.com> <3e57ba64-732b-d5be-1ad6-eecc731ef405@suse.cz> <20190807003109.GB24750@richard> <20190807075101.GN11812@dhcp22.suse.cz> <20190808032638.GA28138@richard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Aug 08, 2019 at 10:49:29AM +0200, Vlastimil Babka wrote: >On 8/8/19 5:26 AM, Wei Yang wrote: >> >> @@ -2270,12 +2270,9 @@ find_vma_prev(struct mm_struct *mm, unsigned long addr, >> if (vma) { >> *pprev = vma->vm_prev; >> } else { >> - struct rb_node *rb_node = mm->mm_rb.rb_node; >> - *pprev = NULL; >> - while (rb_node) { >> - *pprev = rb_entry(rb_node, struct vm_area_struct, vm_rb); >> - rb_node = rb_node->rb_right; >> - } >> + struct rb_node *rb_node = rb_last(&mm->mm_rb); >> + *pprev = !rb_node ? NULL : >> + rb_entry(rb_node, struct vm_area_struct, vm_rb); >> } >> return vma; >> >> Not sure this style would help a little in understanding the code? > >Yeah using rb_last() would be nicer than basically repeating its >implementation, so it's fine as a cleanup without performance implications. > Thanks, I would send this version with proper change log. >>> -- >>> Michal Hocko >>> SUSE Labs >> -- Wei Yang Help you, Help me