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 DCCBF222592 for ; Wed, 26 Feb 2025 17:00:01 +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=1740589201; cv=none; b=pbAJMIfXR0CBQhoQOzk9IjAlX0SgizwynCHM9G6Nu/8iQBdObD/+gaFDCyN4xsLIPLJ2xlMvxyiIouskMiJyOJ1ETc1XxTP+zftWW4U+YctpDhkgZuwI6jTyci/xR3Qsr9J6g+z6Bu5tws0aWW6D5/5DmwOVQ5DyUm7nIKcl0dk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740589201; c=relaxed/simple; bh=trIEL+zgCm8CqDraZqRe8QcfXKurHnZJJq+wOufsgR4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=LfjKz/BTIgYfJIXmD1ZsAj0jhkVgDRj/+1xf5/VIl4+1XscHEr239EAxX22q1KdohFkdeKaj/+GyHFWeD3aNxTI3Aakg7u8EU95assUE49CkQ0jp7yNfS912KzV0n7P7vHo8+FOq/oCJqbqPpi8rXxlNE4cFKlukvS4NC9FUE58= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MTb0dlc6; 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="MTb0dlc6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B3F7AC4CED6; Wed, 26 Feb 2025 17:00:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1740589201; bh=trIEL+zgCm8CqDraZqRe8QcfXKurHnZJJq+wOufsgR4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=MTb0dlc6w4XIM9j79pOs6c0q9PioTgDpl54scViSkvf1rD3dyQuySyDMGO4O59sqK jeobef+1B2qXNFvNsYn40LMJwi4n68EhDMmRTOd6aZWpUlhtfJSyyG2bTrzDwcdGLk wUdThY8IyTfolZ0oEjt6Bqw+XLjXLRF7a4SZPWldgdjeFYN/1sLDv5kacwuWR8TiLY OelzEMrJ1mFELtVw6u/zdJNeKzMEy3K6QhW9mAeyO1xMylvxOEw7t+qrTVPirS2tW6 DfMdrr4anodXeU9cJjmVIksp2Y2bmNQQpmLSf9mMtK1gw4D3g40Q8GfYZvyKTckanz CHlLUNv16oAvg== Date: Wed, 26 Feb 2025 09:00:01 -0800 From: "Darrick J. Wong" To: Christoph Hellwig Cc: Carlos Maiolino , Dave Chinner , linux-xfs@vger.kernel.org Subject: Re: [PATCH 02/12] xfs: add a fast path to xfs_buf_zero when b_addr is set Message-ID: <20250226170001.GM6242@frogsfrogsfrogs> References: <20250226155245.513494-1-hch@lst.de> <20250226155245.513494-3-hch@lst.de> 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: <20250226155245.513494-3-hch@lst.de> On Wed, Feb 26, 2025 at 07:51:30AM -0800, Christoph Hellwig wrote: > No need to walk the page list if bp->b_addr is valid. That also means > b_offset doesn't need to be taken into account in the unmapped loop as > b_offset is only set for kmem backed buffers which are always mapped. > > Signed-off-by: Christoph Hellwig That's much clearer! Reviewed-by: "Darrick J. Wong" --D > --- > fs/xfs/xfs_buf.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c > index 15bb790359f8..9e0c64511936 100644 > --- a/fs/xfs/xfs_buf.c > +++ b/fs/xfs/xfs_buf.c > @@ -1688,13 +1688,18 @@ xfs_buf_zero( > { > size_t bend; > > + if (bp->b_addr) { > + memset(bp->b_addr + boff, 0, bsize); > + return; > + } > + > bend = boff + bsize; > while (boff < bend) { > struct page *page; > int page_index, page_offset, csize; > > - page_index = (boff + bp->b_offset) >> PAGE_SHIFT; > - page_offset = (boff + bp->b_offset) & ~PAGE_MASK; > + page_index = boff >> PAGE_SHIFT; > + page_offset = boff & ~PAGE_MASK; > page = bp->b_pages[page_index]; > csize = min_t(size_t, PAGE_SIZE - page_offset, > BBTOB(bp->b_length) - boff); > -- > 2.45.2 > >