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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 23DD7C43334 for ; Mon, 20 Jun 2022 01:37:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6850B6B0072; Sun, 19 Jun 2022 21:37:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 636B96B0073; Sun, 19 Jun 2022 21:37:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 524C56B0074; Sun, 19 Jun 2022 21:37:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 43CD86B0072 for ; Sun, 19 Jun 2022 21:37:52 -0400 (EDT) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 1434C33946 for ; Mon, 20 Jun 2022 01:37:52 +0000 (UTC) X-FDA: 79596902784.04.B4F9E4A Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by imf01.hostedemail.com (Postfix) with ESMTP id 0577240010 for ; Mon, 20 Jun 2022 01:37:50 +0000 (UTC) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.54]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4LRBzz2Kcrz1KC2d; Mon, 20 Jun 2022 09:35:43 +0800 (CST) Received: from [10.174.177.76] (10.174.177.76) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 20 Jun 2022 09:37:47 +0800 Subject: Re: [PATCH] mm/madvise: minor cleanup for swapin_walk_pmd_entry() To: Andrew Morton CC: , References: <20220618090527.37843-1-linmiaohe@huawei.com> <20220618115909.5f2d1a4da68cc4115e73d14a@linux-foundation.org> From: Miaohe Lin Message-ID: Date: Mon, 20 Jun 2022 09:37:46 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20220618115909.5f2d1a4da68cc4115e73d14a@linux-foundation.org> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.177.76] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1655689071; a=rsa-sha256; cv=none; b=UdyXSOAUxpjFRmwQL6VNtw2BbglZGAI48dBuOCLG7XJ8mSEIHPC9I+mSPEHBnEpTzob8gw KeQgT0GsB/2+URGe6wjS0Kt0SrJIIPB9vnkt3xH2h9uatAO2zoAFhk4e3Tckt2PcFzGf0S FW3vXlUtBkrcf5Do+lH2tlBNBoGoP9w= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf01.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.255 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1655689071; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=skx0dnaMr27Y3OudZaGqi0JNjwfeyFe0f+OGpDHAG2g=; b=W1pDvuuhhsC3oEQ5b/nW3zoCW1NU/e5GDkGa4WD3GrnDunjgl3SAFbl/sVVbhlOu9ccpoH s6x+vFhLpAwoJqT2txMK6v6KAtye5HxMPqGylHfalKhoyiJKrj8ZdipYBvlKn8GDxaihc3 0yNtxMj3Ag7IzBquvM8ZzTm4udQSD9c= X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 0577240010 X-Stat-Signature: cy1m8b944dcb8u4oba3mwqhyprs5nimk X-Rspam-User: Authentication-Results: imf01.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf01.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.255 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com X-HE-Tag: 1655689070-750295 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 2022/6/19 2:59, Andrew Morton wrote: > On Sat, 18 Jun 2022 17:05:27 +0800 Miaohe Lin wrote: > >> Passing index to pte_offset_map_lock() directly so the below calculation >> can be avoided. Rename orig_pte to ptep as it's not changed. Also use >> helper is_swap_pte() to improve the readability. No functional change >> intended. >> >> ... >> >> --- a/mm/madvise.c >> +++ b/mm/madvise.c >> @@ -195,7 +195,7 @@ static int madvise_update_vma(struct vm_area_struct *vma, >> static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start, >> unsigned long end, struct mm_walk *walk) >> { >> - pte_t *orig_pte; >> + pte_t *ptep; >> struct vm_area_struct *vma = walk->private; >> unsigned long index; >> struct swap_iocb *splug = NULL; >> @@ -209,11 +209,11 @@ static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start, >> struct page *page; >> spinlock_t *ptl; >> >> - orig_pte = pte_offset_map_lock(vma->vm_mm, pmd, start, &ptl); >> - pte = *(orig_pte + ((index - start) / PAGE_SIZE)); >> - pte_unmap_unlock(orig_pte, ptl); >> + ptep = pte_offset_map_lock(vma->vm_mm, pmd, index, &ptl); >> + pte = *ptep; >> + pte_unmap_unlock(ptep, ptl); >> >> - if (pte_present(pte) || pte_none(pte)) >> + if (!is_swap_pte(pte)) >> continue; >> entry = pte_to_swp_entry(pte); >> if (unlikely(non_swap_entry(entry))) > > Also... > > From: Andrew Morton > Subject: mm-madvise-minor-cleanup-for-swapin_walk_pmd_entry-fix > Date: Sat Jun 18 11:58:03 AM PDT 2022 > > reduce scope of `ptep' Looks good to me. Thanks for doing this. :) > > Cc: Miaohe Lin > Signed-off-by: Andrew Morton > --- > > mm/madvise.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > --- a/mm/madvise.c~mm-madvise-minor-cleanup-for-swapin_walk_pmd_entry-fix > +++ a/mm/madvise.c > @@ -195,7 +195,6 @@ success: > static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start, > unsigned long end, struct mm_walk *walk) > { > - pte_t *ptep; > struct vm_area_struct *vma = walk->private; > unsigned long index; > struct swap_iocb *splug = NULL; > @@ -208,6 +207,7 @@ static int swapin_walk_pmd_entry(pmd_t * > swp_entry_t entry; > struct page *page; > spinlock_t *ptl; > + pte_t *ptep; > > ptep = pte_offset_map_lock(vma->vm_mm, pmd, index, &ptl); > pte = *ptep; > _ > > . >