From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-112.freemail.mail.aliyun.com (out30-112.freemail.mail.aliyun.com [115.124.30.112]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9047C29A5 for ; Fri, 21 Jun 2024 03:39:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.112 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718941158; cv=none; b=ht8iUMQbshPvVcAAvyxlifTb40+t7pQjgxJovs7xfjWm0WrS7JKZgfRpCiVhwoLKf4cXSmWOHzOpgnrR3kjTMyrJkRQDMBVXef8g7YOCEP3R9+BwMLVZzWV0vG1+J5kGfIdxAzd7AhuK76mJ3AW4yqrcDXgPsviqg8aZ91FaH3s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718941158; c=relaxed/simple; bh=JsSR1xBwj1gkY4SqWbJVApmJVPD1laD4eNL1OJuerMk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=JcA/fdLxc7FIExZky3lu+iQ6zul2vKD08Y7aIm/Yl2r/vXKgDSt78WKKn+aQYzb87zl28imdq+Y7rHDt/Nj900jwYFpLhOFGR66eOAegIwOND8WFtV29Fyep1Z8GL/OE7WXDTj9ocIeu0cCmhebXOkG65jv1QZ7ccWejC2Y5LV0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=VoW4T/Wm; arc=none smtp.client-ip=115.124.30.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="VoW4T/Wm" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1718941152; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=WMQicdjofrQpjTY14SHJsetHY5HbBnIjFn+Mnq60DqI=; b=VoW4T/Wm2iqhhhC9Qcdh/zu1CrxAb45VUFuS8iapyc0njfZ6dBQSQ1/qJr/WMfM4RrV7nnCOmmKFmMYAw+6kbuWoZUvzWhz6LCumoh7ST6woX/O7sFXMrhmWYRSXwyzTpng6NuWYix3ZMtuYhF85rAsvAq5VREj6rNAPNQHSQXo= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R151e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam033037067113;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0W8upPoS_1718941150; Received: from 192.168.43.81(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0W8upPoS_1718941150) by smtp.aliyun-inc.com; Fri, 21 Jun 2024 11:39:11 +0800 Message-ID: Date: Fri, 21 Jun 2024 11:39:09 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 1/2] mm/migrate: make migrate_misplaced_folio() return 0 on success To: David Hildenbrand , linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, Andrew Morton References: <20240620212935.656243-1-david@redhat.com> <20240620212935.656243-2-david@redhat.com> From: Baolin Wang In-Reply-To: <20240620212935.656243-2-david@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2024/6/21 05:29, David Hildenbrand wrote: > Let's just return 0 on success, which is less confusing. > > ... especially because we got it wrong in the migrate.h stub where we > have "return -EAGAIN; /* can't migrate now */" instead of "return 0;". > Likely this wrong return value doesn't currently matter, but it > certainly adds confusion. > > We'll add migrate_misplaced_folio_prepare() next, where we want to use > the same "return 0 on success" approach, so let's just clean this up LGTM. Reviewed-by: Baolin Wang > > Signed-off-by: David Hildenbrand > --- > mm/huge_memory.c | 5 ++--- > mm/memory.c | 2 +- > mm/migrate.c | 4 ++-- > 3 files changed, 5 insertions(+), 6 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 0fffaa58a47a..fc27dabcd8e3 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -1652,7 +1652,7 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) > unsigned long haddr = vmf->address & HPAGE_PMD_MASK; > int nid = NUMA_NO_NODE; > int target_nid, last_cpupid = (-1 & LAST_CPUPID_MASK); > - bool migrated = false, writable = false; > + bool writable = false; > int flags = 0; > > vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); > @@ -1696,8 +1696,7 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) > spin_unlock(vmf->ptl); > writable = false; > > - migrated = migrate_misplaced_folio(folio, vma, target_nid); > - if (migrated) { > + if (!migrate_misplaced_folio(folio, vma, target_nid)) { > flags |= TNF_MIGRATED; > nid = target_nid; > } else { > diff --git a/mm/memory.c b/mm/memory.c > index 00728ea95583..118660de5bcc 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -5354,7 +5354,7 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf) > ignore_writable = true; > > /* Migrate to the requested node */ > - if (migrate_misplaced_folio(folio, vma, target_nid)) { > + if (!migrate_misplaced_folio(folio, vma, target_nid)) { > nid = target_nid; > flags |= TNF_MIGRATED; > } else { > diff --git a/mm/migrate.c b/mm/migrate.c > index 781979567f64..0307b54879a0 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -2629,11 +2629,11 @@ int migrate_misplaced_folio(struct folio *folio, struct vm_area_struct *vma, > nr_succeeded); > } > BUG_ON(!list_empty(&migratepages)); > - return isolated; > + return isolated ? 0 : -EAGAIN; > > out: > folio_put(folio); > - return 0; > + return -EAGAIN; > } > #endif /* CONFIG_NUMA_BALANCING */ > #endif /* CONFIG_NUMA */