From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 773832063F1 for ; Fri, 10 Jan 2025 06:25:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736490331; cv=none; b=MddcDkXtHkjEEnnGAsrFROzD6nPM0umoqpo0v8rVJQ9imM+M2hhWBRYxFFnTCOg8dc6HELBO0j5gzPwbUUpRqCgP2KkCnmDW4UZhk4hz6yxHtAF2w+FWgHj7MSdIFnuA8xz9o4n6e784XsjPnamVLD7VwgPcBPPMW82n/Ks1Cug= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736490331; c=relaxed/simple; bh=JJweyQo1mp0HrUSNwfi/D449V9RQ9JAtHsnXuzDchPg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=pUoV84u067rQVth0yi+JHlD/A1TktBBIWHnzaWmBEDrTrwChc1b65wSwOjtFjaO4od8tKusUTNAKY3US3B0SdsNpZZD+oJa3QKclqOrLFenrckwpfGUj05pMT76mQJIy13JnTGgzmpBH7RiVWI3I8FmzKf6JPHw2AzgIjqK7A/U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 089291480; Thu, 9 Jan 2025 22:25:57 -0800 (PST) Received: from [10.162.42.21] (K4MQJ0H1H2.blr.arm.com [10.162.42.21]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F04213F673; Thu, 9 Jan 2025 22:25:16 -0800 (PST) Message-ID: Date: Fri, 10 Jan 2025 11:55:13 +0530 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: [RFC 01/11] introduce khugepaged_collapse_single_pmd to collapse a single pmd To: Nico Pache , linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: ryan.roberts@arm.com, anshuman.khandual@arm.com, catalin.marinas@arm.com, cl@gentwo.org, vbabka@suse.cz, mhocko@suse.com, apopple@nvidia.com, dave.hansen@linux.intel.com, will@kernel.org, baohua@kernel.org, jack@suse.cz, srivatsa@csail.mit.edu, haowenchao22@gmail.com, hughd@google.com, aneesh.kumar@kernel.org, yang@os.amperecomputing.com, peterx@redhat.com, ioworker0@gmail.com, wangkefeng.wang@huawei.com, ziy@nvidia.com, jglisse@google.com, surenb@google.com, vishal.moola@gmail.com, zokeefe@google.com, zhengqi.arch@bytedance.com, jhubbard@nvidia.com, 21cnbao@gmail.com, willy@infradead.org, kirill.shutemov@linux.intel.com, david@redhat.com, aarcange@redhat.com, raquini@redhat.com, sunnanyong@huawei.com, usamaarif642@gmail.com, audra@redhat.com, akpm@linux-foundation.org References: <20250108233128.14484-1-npache@redhat.com> <20250108233128.14484-2-npache@redhat.com> Content-Language: en-US From: Dev Jain In-Reply-To: <20250108233128.14484-2-npache@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 09/01/25 5:01 am, Nico Pache wrote: > The khugepaged daemon and madvise_collapse have two different > implementations that do almost the thing. > > Create khugepaged_collapse_single_pmd to increase code > reuse and create a entry point for future khugepaged changes. > > Signed-off-by: Nico Pache > --- > mm/khugepaged.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 46 insertions(+) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 653dbb1ff05c..4d932839ff1d 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -2348,6 +2348,52 @@ static int hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr, > } > #endif > > +/* > + * Try to collapse a single PMD starting at a PMD aligned addr, and return > + * the results. > + */ > +static int khugepaged_collapse_single_pmd(unsigned long addr, struct mm_struct *mm, > + struct vm_area_struct *vma, bool *mmap_locked, > + struct collapse_control *cc) > +{ > + int result = SCAN_FAIL; > + unsigned long tva_flags = cc->is_khugepaged ? TVA_ENFORCE_SYSFS : 0; > + > + if (!*mmap_locked) { > + mmap_read_lock(mm); > + *mmap_locked = true; > + } > + > + if (thp_vma_allowable_order(vma, vma->vm_flags, > + tva_flags, PMD_ORDER)) { > + if (IS_ENABLED(CONFIG_SHMEM) && vma->vm_file) { > + struct file *file = get_file(vma->vm_file); > + pgoff_t pgoff = linear_page_index(vma, addr); > + > + mmap_read_unlock(mm); > + *mmap_locked = false; > + result = hpage_collapse_scan_file(mm, addr, file, pgoff, > + cc); > + fput(file); > + if (result == SCAN_PTE_MAPPED_HUGEPAGE) { > + mmap_read_lock(mm); > + if (hpage_collapse_test_exit_or_disable(mm)) > + goto end; > + result = collapse_pte_mapped_thp(mm, addr, > + !cc->is_khugepaged); > + mmap_read_unlock(mm); > + } > + } else { > + result = hpage_collapse_scan_pmd(mm, vma, addr, > + mmap_locked, cc); > + } > + if (result == SCAN_SUCCEED || result == SCAN_PMD_MAPPED) > + ++khugepaged_pages_collapsed; > + } > +end: > + return result; > +} > + > static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result, > struct collapse_control *cc) > __releases(&khugepaged_mm_lock) I will suggest squashing this with patch 2 to avoid unused function warning when sequentially building patches.