From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7541315574D; Tue, 9 Jul 2024 21:59:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720562359; cv=none; b=MbKidno0CmrvHnISKnvt7Ia4GVNiIOM0t9/BstzKcGUAENwQ2rxEL93X+3xJOo+B9jWivlaudQe4uZMYuQ/ohvbChVjxyLGlS5HgqnJNIA3i3mU48wSTI5pdmJKYcGgM4v1mdePR31A4S4G/llvtIEawNCPq9n+ysL1wKbK+U5k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720562359; c=relaxed/simple; bh=gJR9+R3Sp+X9MDHtGXK+187J/tLYoRv4pK+2NdBCMnw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=PSNPqeLMBtlFlEHQRNqYGqPFGldnsxvyHU6ynBj/rswHOACx7tNh4/0vfCGwbHME2GKa0ulED/WRO+UIgFuGLmUotMWkWkp7VHywJtoap9EctnJ7KtWteFaXJGF/6pXZuKbzPzV9GcxP4deJkEjKwWE1rLUovntp+ZwpnU9IPfg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qrFdG7XC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="qrFdG7XC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 020D9C3277B; Tue, 9 Jul 2024 21:59:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720562359; bh=gJR9+R3Sp+X9MDHtGXK+187J/tLYoRv4pK+2NdBCMnw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qrFdG7XCGLOOpEaTEEkx5EgR5W6BwnZ8GIaRyOty4hmQqtqicvqzY1kwqdLslE02s i22EOi3o5yGSTgnk6uawtJt4T+ZOnafHgmEvL42BvBb9vZEJn5n2LKOZuhP6kkpAzJ Z9r0t9LGKtG+ywgdW41+VNfHrS+IUsaNbVX0enlYVQY8iu0PRrvqLACUecEx1di9GP R0wX5t5kLiBU5eTS7PDmWusszfqt0PQgnktJ41ka/Kel6cdMHYGwbFEiGUplvAuYLR ttQHNcUnRbBlXGdHjgjyXDP5xBakY3Dg2usV3i2YXcMPMcCU4Xpy4l1Ujs255Ft5BT UgmI0KHTxvhVA== Date: Tue, 9 Jul 2024 14:59:18 -0700 From: "Darrick J. Wong" To: "Pankaj Raghav (Samsung)" Cc: david@fromorbit.com, willy@infradead.org, ryan.roberts@arm.com, linux-kernel@vger.kernel.org, yang@os.amperecomputing.com, linux-mm@kvack.org, john.g.garry@oracle.com, linux-fsdevel@vger.kernel.org, hare@suse.de, p.raghav@samsung.com, mcgrof@kernel.org, gost.dev@samsung.com, cl@os.amperecomputing.com, linux-xfs@vger.kernel.org, hch@lst.de, Zi Yan , akpm@linux-foundation.org, chandan.babu@oracle.com Subject: Re: [PATCH v8 01/10] fs: Allow fine-grained control of folio sizes Message-ID: <20240709215918.GD612460@frogsfrogsfrogs> References: <20240625114420.719014-1-kernel@pankajraghav.com> <20240625114420.719014-2-kernel@pankajraghav.com> <20240709162907.gsd5nf33teoss5ir@quentin> <20240709165047.GS1998502@frogsfrogsfrogs> <20240709210829.dgm6dsirkry3fgu6@quentin> Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240709210829.dgm6dsirkry3fgu6@quentin> On Tue, Jul 09, 2024 at 09:08:29PM +0000, Pankaj Raghav (Samsung) wrote: > > > > > > - We make THP an explicit dependency for XFS: > > > > > > diff --git a/fs/xfs/Kconfig b/fs/xfs/Kconfig > > > index d41edd30388b7..be2c1c0e9fe8b 100644 > > > --- a/fs/xfs/Kconfig > > > +++ b/fs/xfs/Kconfig > > > @@ -5,6 +5,7 @@ config XFS_FS > > > select EXPORTFS > > > select LIBCRC32C > > > select FS_IOMAP > > > + select TRANSPARENT_HUGEPAGE > > > help > > > XFS is a high performance journaling filesystem which originated > > > on the SGI IRIX platform. It is completely multi-threaded, can > > > > > > OR > > > > > > We create a helper in page cache that FSs can use to check if a specific > > > order can be supported at mount time: > > > > I like this solution better; if XFS is going to drop support for o[ld]d > > architectures I think we need /some/ sort of notice period. Or at least > > a better story than "we want to support 64k fsblocks on x64 so we're > > withdrawing support even for 4k fsblocks and smallish filesystems on > > m68k". > > > > You probably don't want bs>ps support to block on some arcane discussion > > about 32-bit, right? ;) > > > > :) > > > > diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h > > > index 14e1415f7dcf..9be775ef11a5 100644 > > > --- a/include/linux/pagemap.h > > > +++ b/include/linux/pagemap.h > > > @@ -374,6 +374,14 @@ static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask) > > > #define MAX_XAS_ORDER (XA_CHUNK_SHIFT * 2 - 1) > > > #define MAX_PAGECACHE_ORDER min(MAX_XAS_ORDER, PREFERRED_MAX_PAGECACHE_ORDER) > > > > > > + > > > +static inline unsigned int mapping_max_folio_order_supported() > > > +{ > > > + if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) > > > + return 0; > > > > Shouldn't this line be indented by two tabs, not six spaces? > > > > > + return MAX_PAGECACHE_ORDER; > > > +} > > > > Alternately, should this return the max folio size in bytes? > > > > static inline size_t mapping_max_folio_size(void) > > { > > if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) > > return 1U << (PAGE_SHIFT + MAX_PAGECACHE_ORDER); > > return PAGE_SIZE; > > } > > We already have mapping_max_folio_size(mapping) which returns the > maximum folio order set for that mapping. So this could be called as > mapping_max_folio_size_supported(). > > So we could just have mapping_max_folio_size_supported() instead of > having mapping_max_folio_order_supported as you suggest. > > > > Then the validation looks like: > > > > const size_t max_folio_size = mapping_max_folio_size(); > > > > if (mp->m_sb.sb_blocksize > max_folio_size) { > > xfs_warn(mp, > > "block size (%u bytes) not supported; maximum folio size is %u.", > > mp->m_sb.sb_blocksize, max_folio_size); > > error = -ENOSYS; > > goto out_free_sb; > > } > > > > (Don't mind me bikeshedding here.) > > > > > + > > > > > > > > > diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c > > > index b8a93a8f35cac..e2be8743c2c20 100644 > > > --- a/fs/xfs/xfs_super.c > > > +++ b/fs/xfs/xfs_super.c > > > @@ -1647,6 +1647,15 @@ xfs_fs_fill_super( > > > goto out_free_sb; > > > } > > > > > > + if (mp->m_sb.sb_blocklog - PAGE_SHIFT > > > > + mapping_max_folio_order_supported()) { > > > + xfs_warn(mp, > > > +"Block Size (%d bytes) is not supported. Check MAX_PAGECACHE_ORDER", > > > + mp->m_sb.sb_blocksize); > > > > You might as well print MAX_PAGECACHE_ORDER here to make analysis > > easier on less-familiar architectures: > > Yes! Thanks. --D > > > > xfs_warn(mp, > > "block size (%d bytes) is not supported; max folio size is %u.", > > mp->m_sb.sb_blocksize, > > 1U << mapping_max_folio_order_supported()); > > > > (I wrote this comment first.) > > > > > --D > > > > > + error = -ENOSYS; > > > + goto out_free_sb; > > > + } > > > + > > > xfs_warn(mp, > > > "EXPERIMENTAL: V5 Filesystem with Large Block Size (%d bytes) enabled.", > > > mp->m_sb.sb_blocksize); > > > > > > > > > -- > > > Pankaj >