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 91EA83FDC08 for ; Wed, 10 Jun 2026 12:44:35 +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=1781095477; cv=none; b=FWJK5RuoroG5axViIyAn77z0jVuBdk5WLkBJ6tlgu6vHDlvf8xaV8xpnKrWd04c/QOpwUyL3yw90l13xM4plKdSCXM8GBHAuxmAQ3F6t3d5861Kqg1rQ08fofNA8XSmecCXKcYmaSXDc5OOUE9rPc88lSdACqe10msXUSsw9ZuI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781095477; c=relaxed/simple; bh=/71fUSWRTKgBH4+4pEJ/O1jAFheHH/gxRrdczIj8DY0=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=GZYCCxJ842eK+I78ZR1XWbESfxGNQ9VnvaljIR0SOW34N2Gglvk4rQSVrxb/27vc4XY2S65r7Z4jOgAW4KQJPARn72Ei4iulqPAmg/1wwtD/gAzPmh2Rrpr3EWvBge3mUwnqTpOq7Dlz8emUD+043DxmMKhltzQQMppnzTo/lkc= 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=gGAqpLHi; 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="gGAqpLHi" 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=1781095473; 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=Hoo+J3C19/L3qqtvBUInYcwgth59RiEZ8NTdgfJnZfg=; b=gGAqpLHinpWJJIMY9244f7levClY2JlKxqRaam3js8ZUqYdvVO4BzvoMjdo4PEpMe8f/ik LTRhPWwq8lfm05w/iNz+U1AZIruvpGtRJqHjB01hEPWOt3adL6p4OCEYTREl2g/rO0Co2M kBSmP/e/a6a0S3mU0msPiGnFlH+lcgU= 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: Wed, 10 Jun 2026 20:44:16 +0800 Message-Id: <20260610124416.46522-1-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: [...] >@@ -1512,8 +1517,12 @@ static enum scan_result mthp_collapse(struct mm_struct *mm, > enum scan_result ret; > > collapse_address = address + offset * PAGE_SIZE; >- ret = collapse_huge_page(mm, collapse_address, referenced, >- unmapped, cc, order); >+ if (file) >+ ret = collapse_file(mm, collapse_address, file, >+ start + offset, cc, order); >+ else >+ ret = collapse_huge_page(mm, collapse_address, >+ referenced, unmapped, cc, order); > > switch (ret) { > /* Cases where we continue to next collapse candidate */ >@@ -1521,6 +1530,7 @@ static enum scan_result mthp_collapse(struct mm_struct *mm, > collapsed += nr_ptes; > fallthrough; > case SCAN_PTE_MAPPED_HUGEPAGE: Looks like SCAN_PTE_MAPPED_HUGEPAGE from collapse_file() get lost for the PMD-order case. Previously, collapse_file() returned it straight back to collapse_single_pmd(), so we would run try_collapse_pte_mapped_thp(). Now it hits mthp_collapse() fitst, and that case just goes to next_offset ... >+ case SCAN_PAGE_COMPOUND: > goto next_offset; > /* Cases where lower orders might still succeed */ > case SCAN_ALLOC_HUGE_PAGE_FAIL: [...] Cheers, Lance