From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout-p-201.mailbox.org (mout-p-201.mailbox.org [80.241.56.171]) (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 9286EB661; Sun, 28 Apr 2024 20:59:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=80.241.56.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714337966; cv=none; b=U/byvuR7mpS3YDw7x1fKTZA1hFGLZfwJ31SvR6yE3OrqSYkIznjqg4S/9GeUWpQqSX5F2k4Q2ytus/qGT7xG7oF9bKDgwxcDovbUz48oBImBxgxi8SlsEl+Alg5NwdPOxFRbRvapBTL0AODSBVCVQ14sIuo74Ll0//FnngVKj1U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714337966; c=relaxed/simple; bh=5Kbw4/D6LUjCS3NHHCH6xj23QMQ+Nuis92riDkbC/Z4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=gm4qqnZ/kIvoE6HkNUbZ8UxWqfTpNjbpBufkkJ4eNooifqX63Ddk7DTCgONDIWgwX505GqgeZlorF4lpOQtUryVynKTKq7c4HcjIVBdXKgi2otwjvOWE3TgY9kSI/Dn24aoERHZplzGrrIH70ikBxpk8teDAdAdutrR3+IiTNaM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=pankajraghav.com; spf=pass smtp.mailfrom=pankajraghav.com; dkim=pass (2048-bit key) header.d=pankajraghav.com header.i=@pankajraghav.com header.b=OwNofpHv; arc=none smtp.client-ip=80.241.56.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=pankajraghav.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pankajraghav.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=pankajraghav.com header.i=@pankajraghav.com header.b="OwNofpHv" Received: from smtp202.mailbox.org (smtp202.mailbox.org [IPv6:2001:67c:2050:b231:465::202]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-201.mailbox.org (Postfix) with ESMTPS id 4VSJjh61y0z9sf0; Sun, 28 Apr 2024 22:59:20 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pankajraghav.com; s=MBO0001; t=1714337960; 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: in-reply-to:in-reply-to:references:references; bh=oVuobLMQ/P3jplHXQkykRM7/2IOlzm4DqmyFCcCzMHA=; b=OwNofpHvCUzTevzwB69MRfcQ4Fbi9zpzM6X5SMfGDBgzn3gynhVV3LCVn3LOwQ2HO96cvw DVDgfgtvtk05RPjYW9QK0rOq4ILVukQC028R4OuVS+CdvMa02NGQC3PLcJHXzg2GDF+fLL Gonw0LlGjlTVqv5AAt8Wb0azbPYvxm5hLx9HUkms218f08GeKdoMw34qjq3VxP+t+VqIeI kMlA1FGAp2VKojjNTlYn//rLUvKx0HZF+G89IMQH8zJ0TShQ1Uptu/KpRlupH+VJSAoZOq 0sMQlXX7XK9JWk+7JKJ+B9turL0HbIhJocLidmpM5TRDcazcHFFa1FM+fPB5Xg== Date: Sun, 28 Apr 2024 20:59:15 +0000 From: "Pankaj Raghav (Samsung)" To: "Darrick J. Wong" Cc: willy@infradead.org, brauner@kernel.org, david@fromorbit.com, chandan.babu@oracle.com, akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, hare@suse.de, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-xfs@vger.kernel.org, mcgrof@kernel.org, gost.dev@samsung.com, p.raghav@samsung.com Subject: Re: [PATCH v4 03/11] filemap: allocate mapping_min_order folios in the page cache Message-ID: <20240428205915.2iocwkcf3edc5y2k@quentin> References: <20240425113746.335530-1-kernel@pankajraghav.com> <20240425113746.335530-4-kernel@pankajraghav.com> <20240426151243.GD360919@frogsfrogsfrogs> Precedence: bulk X-Mailing-List: linux-fsdevel@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: <20240426151243.GD360919@frogsfrogsfrogs> X-Rspamd-Queue-Id: 4VSJjh61y0z9sf0 On Fri, Apr 26, 2024 at 08:12:43AM -0700, Darrick J. Wong wrote: > On Thu, Apr 25, 2024 at 01:37:38PM +0200, Pankaj Raghav (Samsung) wrote: > > From: Luis Chamberlain > > > > 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. > > If we cannot find a folio of at least min_order size, what error is sent > back? > > If the answer is "the same error that you get if we cannot allocate a > base page today (aka ENOMEM)", then I think I understand this enough to > say > > Reviewed-by: Darrick J. Wong Yes. We will get a ENOMEM if we cannot allocate min_order size folio. :) Thanks! > > --D > > > Signed-off-by: Luis Chamberlain > > Co-developed-by: Pankaj Raghav > > Signed-off-by: Pankaj Raghav > > --- > > mm/filemap.c | 24 +++++++++++++++++------- > > 1 file changed, 17 insertions(+), 7 deletions(-) > > > > diff --git a/mm/filemap.c b/mm/filemap.c > > index 30de18c4fd28..f0c0cfbbd134 100644 > > --- a/mm/filemap.c > > +++ b/mm/filemap.c > > @@ -858,6 +858,8 @@ 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); > > > > if (!huge) { > > @@ -1895,8 +1897,10 @@ 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; > > @@ -1936,7 +1940,7 @@ 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; > > @@ -2425,13 +2429,16 @@ 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; > > > > @@ -2449,6 +2456,8 @@ 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) > > @@ -2509,8 +2518,7 @@ 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; > > @@ -3708,9 +3716,11 @@ 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); > > -- > > 2.34.1 > > > >