From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A2372C10F03 for ; Fri, 1 Mar 2019 21:09:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F83020818 for ; Fri, 1 Mar 2019 21:09:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551474596; bh=nlkMewMz0qAEgjKrUhDUDxY8LMfcqRB0ad3+SqMqqHY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=bY/NYGmAnKfU8iK2/XUCt4TDN4ypw5gSUOMN+hKV27jsiDuEP5XyvuewZRzV4Gg+9 d18ELxtKYDd8P8PeRVn+dR0nbCu3lZ3ovpdeZ5FrqbJMUORiolDm8WwLI6+YX1NB2C 7k8ixneIlOQawQM1pR+4kdtjzXwzHaJmgVJJa8i8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726596AbfCAVJy (ORCPT ); Fri, 1 Mar 2019 16:09:54 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:54480 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725982AbfCAVJy (ORCPT ); Fri, 1 Mar 2019 16:09:54 -0500 Received: from akpm3.svl.corp.google.com (unknown [104.133.8.65]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 826EFDD20; Fri, 1 Mar 2019 21:09:53 +0000 (UTC) Date: Fri, 1 Mar 2019 13:09:51 -0800 From: Andrew Morton To: Qian Cai Cc: willy@infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/hugepages: fix "orig_pud" set but not used Message-Id: <20190301130951.67f419011da93265d36226cc@linux-foundation.org> In-Reply-To: <20190301004903.89514-1-cai@lca.pw> References: <20190301004903.89514-1-cai@lca.pw> X-Mailer: Sylpheed 3.6.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 28 Feb 2019 19:49:03 -0500 Qian Cai wrote: > The commit a00cc7d9dd93 ("mm, x86: add support for PUD-sized transparent > hugepages") introduced pudp_huge_get_and_clear_full() but no one uses > its return code, so just make it void. > > mm/huge_memory.c: In function 'zap_huge_pud': > mm/huge_memory.c:1982:8: warning: variable 'orig_pud' set but not used > [-Wunused-but-set-variable] > pud_t orig_pud; > ^~~~~~~~ > > ... > > --- a/include/asm-generic/pgtable.h > +++ b/include/asm-generic/pgtable.h > @@ -167,11 +167,11 @@ static inline pmd_t pmdp_huge_get_and_clear_full(struct mm_struct *mm, > #endif > > #ifndef __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR_FULL > -static inline pud_t pudp_huge_get_and_clear_full(struct mm_struct *mm, > - unsigned long address, pud_t *pudp, > - int full) > +static inline void pudp_huge_get_and_clear_full(struct mm_struct *mm, > + unsigned long address, > + pud_t *pudp, int full) > { > - return pudp_huge_get_and_clear(mm, address, pudp); > + pudp_huge_get_and_clear(mm, address, pudp); > } Not sure this is a good change. Future callers might want that return value. > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -1979,7 +1979,6 @@ spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) > int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, > pud_t *pud, unsigned long addr) > { > - pud_t orig_pud; > spinlock_t *ptl; > > ptl = __pud_trans_huge_lock(pud, vma); > @@ -1991,8 +1990,7 @@ int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, > * pgtable_trans_huge_withdraw after finishing pudp related > * operations. > */ > - orig_pud = pudp_huge_get_and_clear_full(tlb->mm, addr, pud, > - tlb->fullmm); > + pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm); In fact this code perhaps should be passing orig_pud into pudp_huge_get_and_clear_full(). That could depend on what future per-arch implementations of pudp_huge_get_and_clear_full() choose to do. Anyway, I'll await Matthew's feedback.