From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-172.mta1.migadu.com (out-172.mta1.migadu.com [95.215.58.172]) (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 B6A6525B09D for ; Thu, 11 Jun 2026 06:06:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781158010; cv=none; b=RR2XsZPIP00uJX0asPg7SdVkeiIREZki2iuXtO7nHsX3b3CBngJ3Y0OjqcF90mptRKBiYIu2vcOIv5Uk2K3XKFDG91jbtctKlJHYTb3Yq4LnTfsx4qt7wIrgje/IFMeAC8spERYtxI2aNApj/4GTDPBo/cyBnF9AAs5abYPnduM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781158010; c=relaxed/simple; bh=6K1KmKxftW3kJ6RH18iQHO5/hizlCzrk051fFhx3s0M=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=EZ5DATn5Dh0fX4c2lhn5vkLLq4fp8YbmzZp93tLl1423gEJM7KvyxkzmKvcvbFZb6u6Yg4keqJ4I0E61l+PnGhQpN+fnQjmMT1ko1sL0WbI4h6wEutoqszOg6ZdjrmRs1YkVsNaRFt20V8308MZevZzIJ4a91uSK+QPM6s/cnBk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=ftEQ4RdY; arc=none smtp.client-ip=95.215.58.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="ftEQ4RdY" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1781158007; h=from:from: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=VY6cPLdBFMgAfHoRWeR+QE2M/b9diN2t5Veaeaq+jOM=; b=ftEQ4RdY3JzZb61UAxo9N15nCfYeH1ESPtYqnyAjeynqSBo43LkPMTTqO9JcKjiEFqHWVF S69PLmCZYqmxG/x0wEF7QkOO2QdjEdRsGD0fs8us2gXWZ7jVGOYvplIaqm9zA46Hyvejsb buz1f6cyS40AP9fHbkhYLyXLvaPrPKA= From: Lance Yang To: baolin.wang@linux.alibaba.com Cc: akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, hughd@google.com, 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, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v2 04/11] mm: khugepaged: add shmem mTHP collapse support Date: Thu, 11 Jun 2026 14:06:19 +0800 Message-Id: <20260611060619.94738-1-lance.yang@linux.dev> In-Reply-To: <3895c09794739bbfae99d9e021ffacf8a51fb8e2.1781083630.git.baolin.wang@linux.alibaba.com> References: <3895c09794739bbfae99d9e021ffacf8a51fb8e2.1781083630.git.baolin.wang@linux.alibaba.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On Wed, Jun 10, 2026 at 06:29:12PM +0800, Baolin Wang wrote: [...] >@@ -2768,15 +2827,23 @@ static enum scan_result collapse_scan_file(struct mm_struct *mm, > else > cc->progress += HPAGE_PMD_NR; > >- if (result == SCAN_SUCCEED) { >- if (present < HPAGE_PMD_NR - max_ptes_none) { >- result = SCAN_EXCEED_NONE_PTE; >- count_vm_event(THP_SCAN_EXCEED_NONE_PTE); >- } else { >- result = collapse_file(mm, addr, file, start, cc, HPAGE_PMD_ORDER); >- } >+ if (result != SCAN_SUCCEED) >+ goto out; >+ >+ if (present < HPAGE_PMD_NR - max_ptes_none) { >+ result = SCAN_EXCEED_NONE_PTE; >+ count_vm_event(THP_SCAN_EXCEED_NONE_PTE); >+ count_mthp_stat(HPAGE_PMD_ORDER, >+ MTHP_STAT_COLLAPSE_EXCEED_NONE); >+ goto out; > } > >+ result = mthp_collapse(mm, file, start, addr, 0, 0, cc, enabled_orders); Feels like the second 0 wants to be "swap", no? >+ if (result == SCAN_SUCCEED && !cc->is_khugepaged) { >+ /* If MADV_COLLAPSE, adjust result to call collapse_pte_mapped_thp(). */ >+ result = SCAN_PTE_MAPPED_HUGEPAGE; >+ } >+out: > trace_mm_khugepaged_scan_file(mm, folio, file, present, swap, result); > return result; > } >@@ -2808,7 +2875,7 @@ static enum scan_result collapse_single_pmd(unsigned long addr, > mmap_read_unlock(mm); > *lock_dropped = true; > retry: >- result = collapse_scan_file(mm, addr, file, pgoff, cc); >+ result = collapse_scan_file(mm, vma, addr, file, pgoff, cc); > > /* > * For MADV_COLLAPSE, when encountering dirty pages, try to writeback, >-- >2.47.3 > >