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 EE343CD128A for ; Thu, 4 Apr 2024 01:45:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 878336B0095; Wed, 3 Apr 2024 21:45:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 827676B0098; Wed, 3 Apr 2024 21:45:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 717156B0099; Wed, 3 Apr 2024 21:45:53 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 52DFB6B0095 for ; Wed, 3 Apr 2024 21:45:53 -0400 (EDT) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 1A07A1C061C for ; Thu, 4 Apr 2024 01:45:53 +0000 (UTC) X-FDA: 81970158186.17.465BF4E Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf20.hostedemail.com (Postfix) with ESMTP id 84F981C0005 for ; Thu, 4 Apr 2024 01:45:51 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=gVJ6EixL; dmarc=none; spf=pass (imf20.hostedemail.com: domain of akpm@linux-foundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1712195151; 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:dkim-signature; bh=nYsQQIqTWk8GLAnN1Y8vpYGS0N61Xbj6oWUg/Khk/+w=; b=NxsQOXRoaJbqao/NKxcvG1obwqiZnfoOnnVOzv+DOZYEWeB0T2zIp6qO7nOQK1PAAQBLgn RiI9okggm2JD4Pm+3aay/1BJMbKoYewA9d0hVxELOLJNfc3PlcV/LcDwV6EXaub8gk3g2Q 7AhOkYSf2d5OLVbapMr37doCXaZGpWo= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=gVJ6EixL; dmarc=none; spf=pass (imf20.hostedemail.com: domain of akpm@linux-foundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1712195151; a=rsa-sha256; cv=none; b=LQgLTQ3Ge9DgC3D7Y4jCmgALyixNV+izPE5AUZMwjV6Wisq5+m/d3Dlj42EA0KKJHd1Bqk dGBpgVhWXM1J3CuYV1vz/MkJnzJQsLakLtfn9M2wBZaiDdXUOybaIvhrTOIfsaE01Cc7YK 9aFee7JRIQr54/l3wFQiBUDGc9fjd9U= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 46DD96120A; Thu, 4 Apr 2024 01:45:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AE9D6C433F1; Thu, 4 Apr 2024 01:45:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1712195148; bh=P9xOk0HEsY0w+rReB+FJuYrZlBuOJi1smPt64Vc8+RA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=gVJ6EixLLNScEfOWep0KOQX66dgIAkF965EkstXCk+5qRi3Ug83/AOIKM0EdbqFCg Xf1GhG8lD5fkRfhdp4hHEj8tDORssW8Pkro/EsY5/lMM9MVPytXhJxXkY9SZWrk7XL DGl74m8yYdnu/82ViINxExulRDM/68Fm9YaDK9eo= Date: Wed, 3 Apr 2024 18:45:48 -0700 From: Andrew Morton To: Jinjiang Tu Cc: , , , , , , Subject: Re: [PATCH] mm/ksm: remove redundant code in ksm_fork Message-Id: <20240403184548.44798417e068b79469505ffb@linux-foundation.org> In-Reply-To: <20240402024934.1093361-1-tujinjiang@huawei.com> References: <20240402024934.1093361-1-tujinjiang@huawei.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 84F981C0005 X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: xg19uapxxskrz4x4qmcdc3auju4epeqx X-HE-Tag: 1712195151-545320 X-HE-Meta: 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 4Q5Nl6aR omwW7 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: List-Subscribe: List-Unsubscribe: On Tue, 2 Apr 2024 10:49:34 +0800 Jinjiang Tu wrote: > Since commit 3c6f33b7273a ("mm/ksm: support fork/exec for prctl"), when a > child process is forked, the MMF_VM_MERGE_ANY flag will be inherited in > mm_init(). So, it's unnecessary to set the flag in ksm_fork(). > > ... > > --- a/include/linux/ksm.h > +++ b/include/linux/ksm.h > @@ -45,16 +45,8 @@ static inline void ksm_might_unmap_zero_page(struct mm_struct *mm, pte_t pte) > > static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) > { > - int ret; > - > - if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags)) { > - ret = __ksm_enter(mm); > - if (ret) > - return ret; > - } > - > - if (test_bit(MMF_VM_MERGE_ANY, &oldmm->flags)) > - set_bit(MMF_VM_MERGE_ANY, &mm->flags); > + if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags)) > + return __ksm_enter(mm); > > return 0; Thanks, I shall queue this up for testing and shall await review input from Stefan and hopefully others.