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 1768418629E for ; Mon, 15 Jul 2024 10:41:07 +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=1721040071; cv=none; b=V7h/AGrYvWXfZAtizIP3c8A3JUbBmclc3vRuoB/li4/WN9bw9Q/UWmVBlrvjL2Xjt32ODOoK4OgpJh6MjJqiVVTe0soPmIZinUMFVGRFhss44Q0Ig6uR/l0JdXBibUy7PjBU2DkNSODk77LvBs2jxRyerLmWPg7aXZ6PP5samPw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721040071; c=relaxed/simple; bh=Q6SJZuKkA/oIZAVFJYqyjou8klMNhAwYc9VTBZAqvsY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=pWPOZdIFuTKpDj0Ne9qD40Zj7B5GNDjCrnxhxc0adtc8gpR0Rys9irxJLLHlbi1u8jS1l0d6sF4iJtll/08BQxDHR0MbTHEcwoMI2ePNVMrEm64K/E3GpjsTJUASmAgLCwrQV1pi00mwJ68J2LJBlKfOy5U2s18IwuHJRzDEePo= 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 78E89DA7; Mon, 15 Jul 2024 03:41:32 -0700 (PDT) Received: from [10.57.75.89] (unknown [10.57.75.89]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 72ED03F766; Mon, 15 Jul 2024 03:41:05 -0700 (PDT) Message-ID: Date: Mon, 15 Jul 2024 11:41:03 +0100 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 v2] mm/huge_memory: Avoid PMD-size page cache if needed Content-Language: en-GB To: Gavin Shan , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, david@redhat.com, willy@infradead.org, baohua@kernel.org, peterx@redhat.com, ziy@nvidia.com, william.kucharski@oracle.com, baolin.wang@linux.alibaba.com, ddutile@redhat.com, shan.gavin@gmail.com References: <20240715000423.316491-1-gshan@redhat.com> From: Ryan Roberts In-Reply-To: <20240715000423.316491-1-gshan@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit [...] > diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h > index 2aa986a5cd1b..c73ad77fa33d 100644 > --- a/include/linux/huge_mm.h > +++ b/include/linux/huge_mm.h > @@ -72,14 +72,20 @@ extern struct kobj_attribute shmem_enabled_attr; > #define THP_ORDERS_ALL_ANON ((BIT(PMD_ORDER + 1) - 1) & ~(BIT(0) | BIT(1))) > > /* > - * Mask of all large folio orders supported for file THP. > + * Mask of all large folio orders supported for file THP. Folios in a DAX > + * file is never split and the MAX_PAGECACHE_ORDER limit does not apply to > + * it. > */ > -#define THP_ORDERS_ALL_FILE (BIT(PMD_ORDER) | BIT(PUD_ORDER)) > +#define THP_ORDERS_ALL_FILE_DAX \ > + (BIT(PMD_ORDER) | BIT(PUD_ORDER)) Appologies if this was already discussed, but if changing _FILE_DEFAULT to advertise all orders 1-MAX_PAGECACHE_ORDER, shouldn't we also change _FILE_DAX to advertise all orders 1-PUD_ORDER ? Or is DAX literally limited to PTE/PMD/PUD? > +#define THP_ORDERS_ALL_FILE_DEFAULT \ > + ((BIT(MAX_PAGECACHE_ORDER + 1) - 1) & ~BIT(0)) > > /* > * Mask of all large folio orders supported for THP. > */ > -#define THP_ORDERS_ALL (THP_ORDERS_ALL_ANON | THP_ORDERS_ALL_FILE) > +#define THP_ORDERS_ALL \ > + (THP_ORDERS_ALL_ANON | THP_ORDERS_ALL_FILE_DAX | THP_ORDERS_ALL_FILE_DEFAULT) > > #define TVA_SMAPS (1 << 0) /* Will be used for procfs */ > #define TVA_IN_PF (1 << 1) /* Page fault handler */ > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 2120f7478e55..4690f33afaa6 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -88,9 +88,17 @@ unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma, > bool smaps = tva_flags & TVA_SMAPS; > bool in_pf = tva_flags & TVA_IN_PF; > bool enforce_sysfs = tva_flags & TVA_ENFORCE_SYSFS; > + unsigned long supported_orders; > + > /* Check the intersection of requested and supported orders. */ > - orders &= vma_is_anonymous(vma) ? > - THP_ORDERS_ALL_ANON : THP_ORDERS_ALL_FILE; > + if (vma_is_anonymous(vma)) > + supported_orders = THP_ORDERS_ALL_ANON; > + else if (vma_is_dax(vma)) > + supported_orders = THP_ORDERS_ALL_FILE_DAX; > + else > + supported_orders = THP_ORDERS_ALL_FILE_DEFAULT; > + > + orders &= supported_orders; > if (!orders) > return 0; >