From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-119.freemail.mail.aliyun.com (out30-119.freemail.mail.aliyun.com [115.124.30.119]) (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 98ECD3C109B; Wed, 10 Jun 2026 10:29:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.119 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781087384; cv=none; b=YtB8gC7tSqZmcRpV08BnTqj3igC7vOmXGr9NdjDweI6S7AVy7K/oOtVUywmVFrKSCyI5IiyYmMGn3BsKz3jWeF/a3ia371ZF2m4AEdo9DFcVUT4M6tVdrALcboiDNK3T8Sw7NABEpPaGa6ZpWwrbQLAJsd6hkWAXEQ6sDPlG6Wc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781087384; c=relaxed/simple; bh=ZFU8zFpoaJ2EqlmsbSVqqhiGQA7AOddp0ISzQ/Qfias=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nI+K/IKTvtv6Ajmi6WppRuXNqABVl9Zp+H1M6C1yzFi5/LZL2xa2CmZFwzjS/4OBlsZWU8IAab4kvZg1y8613O2n6VyWrNsqULBQL9cJquhC7AHrDE6S5om60j3eaBT2VKIypJxRL6t6/7/hLHpkbCelpGWp1+GCy19g1aVOiE8= 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=BZyYS8LB; arc=none smtp.client-ip=115.124.30.119 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="BZyYS8LB" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1781087373; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=qEB/1EhxVw7xHTTvXrEFTFQel1qTuMuF1xr/NGxBIHM=; b=BZyYS8LBiPtLXe6DqtT9qNSmTrPy39HAJWRPzAYHP+ATOzdMnOV5UmQvLxZptJmrL/WxmX8wcEMfSuhYPWQ9KuGtEO2TwZ0Edv8vIeSK6GHTQovvaM+vKVrDku5LEagM0GsioIeL/aNXjJzJlO1/Qw54Dr5E0lm0YX5aC1Xajyo= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R191e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam033037026112;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=16;SR=0;TI=SMTPD_---0X4aI8Vv_1781087371; Received: from localhost(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0X4aI8Vv_1781087371 cluster:ay36) by smtp.aliyun-inc.com; Wed, 10 Jun 2026 18:29:31 +0800 From: Baolin Wang To: akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, hughd@google.com Cc: willy@infradead.org, ziy@nvidia.com, liam@infradead.org, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, baolin.wang@linux.alibaba.com, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH v2 02/11] mm: khugepaged: generalize collapse_file() for shmem mTHP support Date: Wed, 10 Jun 2026 18:29:10 +0800 Message-ID: <1274846e121e74f8db53950bec64f8f1938f2ec9.1781083630.git.baolin.wang@linux.alibaba.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Generalize the order of the collapse_file() function to support future shmem mTHP collapse. No functional changes in this patch. Signed-off-by: Baolin Wang --- mm/khugepaged.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 631459172e19..4adc8c6de062 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -2214,6 +2214,7 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff) * @file: file that collapse on * @start: collapse start address * @cc: collapse context and scratchpad + * @order: folio order being collapsed to * * Basic scheme is simple, details are more complex: * - allocate and lock a new huge page; @@ -2232,15 +2233,17 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff) * + unlock and free huge page; */ static enum scan_result collapse_file(struct mm_struct *mm, unsigned long addr, - struct file *file, pgoff_t start, struct collapse_control *cc) + struct file *file, pgoff_t start, struct collapse_control *cc, + int order) { - const unsigned int max_ptes_none = collapse_max_ptes_none(cc, NULL, HPAGE_PMD_ORDER); + const unsigned int max_ptes_none = collapse_max_ptes_none(cc, NULL, order); struct address_space *mapping = file->f_mapping; + const unsigned long nr_pages = 1UL << order; struct page *dst; struct folio *folio, *tmp, *new_folio; - pgoff_t index = 0, end = start + HPAGE_PMD_NR; + pgoff_t index = 0, end = start + nr_pages; LIST_HEAD(pagelist); - XA_STATE_ORDER(xas, &mapping->i_pages, start, HPAGE_PMD_ORDER); + XA_STATE_ORDER(xas, &mapping->i_pages, start, order); enum scan_result result = SCAN_SUCCEED; int nr_none = 0; bool is_shmem = shmem_file(file); @@ -2252,9 +2255,9 @@ static enum scan_result collapse_file(struct mm_struct *mm, unsigned long addr, * mapping, the shmem check can be removed. */ VM_WARN_ON_ONCE(!is_shmem && !mapping_pmd_folio_support(mapping)); - VM_WARN_ON_ONCE(start & (HPAGE_PMD_NR - 1)); + VM_WARN_ON_ONCE(start & (nr_pages - 1)); - result = alloc_charge_folio(&new_folio, mm, cc, HPAGE_PMD_ORDER); + result = alloc_charge_folio(&new_folio, mm, cc, order); if (result != SCAN_SUCCEED) goto out; @@ -2591,12 +2594,12 @@ static enum scan_result collapse_file(struct mm_struct *mm, unsigned long addr, } if (is_shmem) { - lruvec_stat_mod_folio(new_folio, NR_SHMEM, HPAGE_PMD_NR); + lruvec_stat_mod_folio(new_folio, NR_SHMEM, nr_pages); lruvec_stat_mod_folio(new_folio, NR_SHMEM_THPS, HPAGE_PMD_NR); } else { lruvec_stat_mod_folio(new_folio, NR_FILE_THPS, HPAGE_PMD_NR); } - lruvec_stat_mod_folio(new_folio, NR_FILE_PAGES, HPAGE_PMD_NR); + lruvec_stat_mod_folio(new_folio, NR_FILE_PAGES, nr_pages); /* * Mark new_folio as uptodate before inserting it into the @@ -2604,14 +2607,14 @@ static enum scan_result collapse_file(struct mm_struct *mm, unsigned long addr, * unwritten page. */ folio_mark_uptodate(new_folio); - folio_ref_add(new_folio, HPAGE_PMD_NR - 1); + folio_ref_add(new_folio, nr_pages - 1); if (is_shmem) folio_mark_dirty(new_folio); folio_add_lru(new_folio); /* Join all the small entries into a single multi-index entry. */ - xas_set_order(&xas, start, HPAGE_PMD_ORDER); + xas_set_order(&xas, start, order); xas_store(&xas, new_folio); WARN_ON_ONCE(xas_error(&xas)); xas_unlock_irq(&xas); @@ -2666,7 +2669,7 @@ static enum scan_result collapse_file(struct mm_struct *mm, unsigned long addr, folio_put(new_folio); out: VM_BUG_ON(!list_empty(&pagelist)); - trace_mm_khugepaged_collapse_file(mm, new_folio, index, addr, is_shmem, file, HPAGE_PMD_NR, result); + trace_mm_khugepaged_collapse_file(mm, new_folio, index, addr, is_shmem, file, nr_pages, result); return result; } @@ -2769,7 +2772,7 @@ static enum scan_result collapse_scan_file(struct mm_struct *mm, result = SCAN_EXCEED_NONE_PTE; count_vm_event(THP_SCAN_EXCEED_NONE_PTE); } else { - result = collapse_file(mm, addr, file, start, cc); + result = collapse_file(mm, addr, file, start, cc, HPAGE_PMD_ORDER); } } -- 2.47.3