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 914021802D7; Wed, 12 Jun 2024 15:40:36 +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=1718206836; cv=none; b=WCKngCDTE2dLbYM51MuwbFmFqhFNmu4xsz8gX9m1WUJHaVii9oBLk9sErqbtmiiTdGw9qINk62+s7RXNM9DkN/oCZnONrHFfmoSjEfN03gz0pVf0XK/6H6pP70Cdp9UO5Dmzl+K44vzNIrA3ayh4cppNEr0sGkLY0KUVSiY5CTw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718206836; c=relaxed/simple; bh=ure0E9PZwCCE0IY9IoqbKopYZ1g301DYRj00CAi1dLM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=T01wG2wIBgFLbEThR2vTP5sd/gsNIErxsE6PkUstJPT/uKSLjEfqtvKFe3QU6qDU3rjUaqiPOP09m9MpGDVAXiYvJT5am+kTB/7GQlIvWy/7FCiMvqVDJiYnxEgSEua2hWuFeUgBBB48Ox/G+gXjamPZX78g+s202y8gW1DaBnM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HktmaJO2; 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="HktmaJO2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 23ECAC116B1; Wed, 12 Jun 2024 15:40:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1718206836; bh=ure0E9PZwCCE0IY9IoqbKopYZ1g301DYRj00CAi1dLM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HktmaJO2RTpRTrqfSR8FlHZ+rsRypeu+fENZHR48jiez8Y2UbDMAcpNYpiD4vQx6S pEnMbNtoaD0mpi9vtHcGOBYwnFSILO/WdcUWkJNbAb3eKh9NqZ4gF6YWetox81MYuG Ue0Bi9wLpBjv8ORF4K+YUM+90DEHh9uJvbdM0hUOs/mQoRAF6H2t8d9caCfCHC2lCq GwzYHi/OmufmuheIhYrF1nnZ558EAly0Db63nSBFO5Vs0GEQC4cancE4ySQ8TXHYNV TxxaJzEZfbxzovsteb40Wbh6rLI5k1aJGoydnLgPWTgfPHvxgfQ52Bh7wIvk95IUj9 ekLXkiHonZ/vw== Date: Wed, 12 Jun 2024 08:40:35 -0700 From: "Darrick J. Wong" To: "Pankaj Raghav (Samsung)" Cc: david@fromorbit.com, chandan.babu@oracle.com, brauner@kernel.org, akpm@linux-foundation.org, willy@infradead.org, mcgrof@kernel.org, linux-mm@kvack.org, hare@suse.de, linux-kernel@vger.kernel.org, yang@os.amperecomputing.com, Zi Yan , linux-xfs@vger.kernel.org, p.raghav@samsung.com, linux-fsdevel@vger.kernel.org, hch@lst.de, gost.dev@samsung.com, cl@os.amperecomputing.com, john.g.garry@oracle.com Subject: Re: [PATCH v7 03/11] filemap: allocate mapping_min_order folios in the page cache Message-ID: <20240612154035.GB2764752@frogsfrogsfrogs> References: <20240607145902.1137853-1-kernel@pankajraghav.com> <20240607145902.1137853-4-kernel@pankajraghav.com> 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: <20240607145902.1137853-4-kernel@pankajraghav.com> On Fri, Jun 07, 2024 at 02:58:54PM +0000, Pankaj Raghav (Samsung) wrote: > From: Pankaj Raghav > > filemap_create_folio() and do_read_cache_folio() were always allocating > folio of order 0. __filemap_get_folio was trying to allocate higher > order folios when fgp_flags had higher order hint set but it will default > to order 0 folio if higher order memory allocation fails. > > Supporting mapping_min_order implies that we guarantee each folio in the > page cache has at least an order of mapping_min_order. When adding new > folios to the page cache we must also ensure the index used is aligned to > the mapping_min_order as the page cache requires the index to be aligned > to the order of the folio. > > Co-developed-by: Luis Chamberlain > Signed-off-by: Luis Chamberlain > Signed-off-by: Pankaj Raghav Seems pretty straightforward, so Reviewed-by: Darrick J. Wong --D > --- > include/linux/pagemap.h | 20 ++++++++++++++++++++ > mm/filemap.c | 26 ++++++++++++++++++-------- > 2 files changed, 38 insertions(+), 8 deletions(-) > > diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h > index 228275e7049f..899b8d751768 100644 > --- a/include/linux/pagemap.h > +++ b/include/linux/pagemap.h > @@ -439,6 +439,26 @@ unsigned int mapping_min_folio_order(const struct address_space *mapping) > return (mapping->flags & AS_FOLIO_ORDER_MIN_MASK) >> AS_FOLIO_ORDER_MIN; > } > > +static inline unsigned long mapping_min_folio_nrpages(struct address_space *mapping) > +{ > + return 1UL << mapping_min_folio_order(mapping); > +} > + > +/** > + * mapping_align_start_index() - Align starting index based on the min > + * folio order of the page cache. > + * @mapping: The address_space. > + * > + * Ensure the index used is aligned to the minimum folio order when adding > + * new folios to the page cache by rounding down to the nearest minimum > + * folio number of pages. > + */ > +static inline pgoff_t mapping_align_start_index(struct address_space *mapping, > + pgoff_t index) > +{ > + return round_down(index, mapping_min_folio_nrpages(mapping)); > +} > + > /* > * Large folio support currently depends on THP. These dependencies are > * being worked on but are not yet fixed. > diff --git a/mm/filemap.c b/mm/filemap.c > index 46c7a6f59788..8bb0d2bc93c5 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -859,6 +859,8 @@ noinline int __filemap_add_folio(struct address_space *mapping, > > VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); > VM_BUG_ON_FOLIO(folio_test_swapbacked(folio), folio); > + VM_BUG_ON_FOLIO(folio_order(folio) < mapping_min_folio_order(mapping), > + folio); > mapping_set_update(&xas, mapping); > > VM_BUG_ON_FOLIO(index & (folio_nr_pages(folio) - 1), folio); > @@ -1919,8 +1921,10 @@ struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index, > folio_wait_stable(folio); > no_page: > if (!folio && (fgp_flags & FGP_CREAT)) { > - unsigned order = FGF_GET_ORDER(fgp_flags); > + unsigned int min_order = mapping_min_folio_order(mapping); > + unsigned int order = max(min_order, FGF_GET_ORDER(fgp_flags)); > int err; > + index = mapping_align_start_index(mapping, index); > > if ((fgp_flags & FGP_WRITE) && mapping_can_writeback(mapping)) > gfp |= __GFP_WRITE; > @@ -1943,7 +1947,7 @@ struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index, > gfp_t alloc_gfp = gfp; > > err = -ENOMEM; > - if (order > 0) > + if (order > min_order) > alloc_gfp |= __GFP_NORETRY | __GFP_NOWARN; > folio = filemap_alloc_folio(alloc_gfp, order); > if (!folio) > @@ -1958,7 +1962,7 @@ struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index, > break; > folio_put(folio); > folio = NULL; > - } while (order-- > 0); > + } while (order-- > min_order); > > if (err == -EEXIST) > goto repeat; > @@ -2447,13 +2451,16 @@ static int filemap_update_page(struct kiocb *iocb, > } > > static int filemap_create_folio(struct file *file, > - struct address_space *mapping, pgoff_t index, > + struct address_space *mapping, loff_t pos, > struct folio_batch *fbatch) > { > struct folio *folio; > int error; > + unsigned int min_order = mapping_min_folio_order(mapping); > + pgoff_t index; > > - folio = filemap_alloc_folio(mapping_gfp_mask(mapping), 0); > + folio = filemap_alloc_folio(mapping_gfp_mask(mapping), > + min_order); > if (!folio) > return -ENOMEM; > > @@ -2471,6 +2478,8 @@ static int filemap_create_folio(struct file *file, > * well to keep locking rules simple. > */ > filemap_invalidate_lock_shared(mapping); > + /* index in PAGE units but aligned to min_order number of pages. */ > + index = (pos >> (PAGE_SHIFT + min_order)) << min_order; > error = filemap_add_folio(mapping, folio, index, > mapping_gfp_constraint(mapping, GFP_KERNEL)); > if (error == -EEXIST) > @@ -2531,8 +2540,7 @@ static int filemap_get_pages(struct kiocb *iocb, size_t count, > if (!folio_batch_count(fbatch)) { > if (iocb->ki_flags & (IOCB_NOWAIT | IOCB_WAITQ)) > return -EAGAIN; > - err = filemap_create_folio(filp, mapping, > - iocb->ki_pos >> PAGE_SHIFT, fbatch); > + err = filemap_create_folio(filp, mapping, iocb->ki_pos, fbatch); > if (err == AOP_TRUNCATED_PAGE) > goto retry; > return err; > @@ -3748,9 +3756,11 @@ static struct folio *do_read_cache_folio(struct address_space *mapping, > repeat: > folio = filemap_get_folio(mapping, index); > if (IS_ERR(folio)) { > - folio = filemap_alloc_folio(gfp, 0); > + folio = filemap_alloc_folio(gfp, > + mapping_min_folio_order(mapping)); > if (!folio) > return ERR_PTR(-ENOMEM); > + index = mapping_align_start_index(mapping, index); > err = filemap_add_folio(mapping, folio, index, gfp); > if (unlikely(err)) { > folio_put(folio); > -- > 2.44.1 > >