linux-kernel - [RFC PATCH 26/53] netfs: Allocate multipage folios in the writepath

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Message-ID: <20231013160423.2218093-27-dhowells@redhat.com>
Date:   Fri, 13 Oct 2023 17:03:55 +0100
From:   David Howells <dhowells@...hat.com>
To:     Jeff Layton <jlayton@...nel.org>, Steve French <smfrench@...il.com>
Cc:     David Howells <dhowells@...hat.com>,
        Matthew Wilcox <willy@...radead.org>,
        Marc Dionne <marc.dionne@...istor.com>,
        Paulo Alcantara <pc@...guebit.com>,
        Shyam Prasad N <sprasad@...rosoft.com>,
        Tom Talpey <tom@...pey.com>,
        Dominique Martinet <asmadeus@...ewreck.org>,
        Ilya Dryomov <idryomov@...il.com>,
        Christian Brauner <christian@...uner.io>,
        linux-afs@...ts.infradead.org, linux-cifs@...r.kernel.org,
        linux-nfs@...r.kernel.org, ceph-devel@...r.kernel.org,
        v9fs@...ts.linux.dev, linux-fsdevel@...r.kernel.org,
        linux-mm@...ck.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-cachefs@...hat.com
Subject: [RFC PATCH 26/53] netfs: Allocate multipage folios in the writepath

Allocate a multipage folio when copying data into the pagecache if possible
if there's sufficient data to warrant it.

Signed-off-by: David Howells <dhowells@...hat.com>
cc: Jeff Layton <jlayton@...nel.org>
cc: linux-cachefs@...hat.com
cc: linux-fsdevel@...r.kernel.org
cc: linux-mm@...ck.org
---
 fs/netfs/buffered_write.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c
index 406c3f3666fa..4de6a12149e4 100644
--- a/fs/netfs/buffered_write.c
+++ b/fs/netfs/buffered_write.c
@@ -84,14 +84,19 @@ static enum netfs_how_to_modify netfs_how_to_modify(struct netfs_inode *ctx,
 }
 
 /*
- * Grab a folio for writing and lock it.
+ * Grab a folio for writing and lock it.  Attempt to allocate as large a folio
+ * as possible to hold as much of the remaining length as possible in one go.
  */
 static struct folio *netfs_grab_folio_for_write(struct address_space *mapping,
 						loff_t pos, size_t part)
 {
 	pgoff_t index = pos / PAGE_SIZE;
+	fgf_t fgp_flags = FGP_WRITEBEGIN;
 
-	return __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
+	if (mapping_large_folio_support(mapping))
+		fgp_flags |= fgf_set_order(pos % PAGE_SIZE + part);
+
+	return __filemap_get_folio(mapping, index, fgp_flags,
 				   mapping_gfp_mask(mapping));
 }