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b=riq+nY01m2S7K/GguawyBy09WBzMdRSYLQUjnnzLIYUWOGc+btM9hBiPQDTgpwoHH sd06n0DwzmdKpMYxVAtGW07CAiqxb3VjTnpzTpC+LmyNPCHTXGneV2EcD33DCnj5Ma DyjbScaLUwPRSUjExECdhdfUtVxFe8dU8vUP7HobrcfnGa9dO78qnqapgtAcx1t56u VWXOmDwnHCbGs7y1qSVjxYDCRGQu+b5YPDK3hGyS5irR+zLQWStF/avuqwHOC7IzgF WQK0wHctEos+kHe8twbeC+RfCrGyr1uo7055sWSEBCSjQ3NW6cNPoydxu9HsG6ZNoz XQn0Ablkfej4Q== Date: Tue, 17 Dec 2024 18:47:53 -0800 From: Luis Chamberlain To: hare@suse.de, willy@infradead.org, dave@stgolabs.net, david@fromorbit.com, djwong@kernel.org, kbusch@kernel.org Cc: john.g.garry@oracle.com, hch@lst.de, ritesh.list@gmail.com, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-block@vger.kernel.org, gost.dev@samsung.com, p.raghav@samsung.com, da.gomez@samsung.com, kernel@pankajraghav.com Subject: Re: [PATCH 5/5] fs/buffer: reduce stack usage on bh_read_iter() Message-ID: References: <20241218022626.3668119-1-mcgrof@kernel.org> <20241218022626.3668119-6-mcgrof@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241218022626.3668119-6-mcgrof@kernel.org> X-Rspamd-Server: rspam05 X-Stat-Signature: 7hicpoctsornjw6nnon6sks7mc9pxam6 X-Rspamd-Queue-Id: 5C2CF1A000E X-Rspam-User: X-HE-Tag: 1734490043-49627 X-HE-Meta: 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 wLjxPpRr /sOdP73xXUm49YHI++rekOgekzIEZyjB9Cxta5DebOQIf8H4skvP6DYvsevpRQ9kcgQSoDvCijsS91Mb6XUT96li2kiCjFKyNo0nTah6DKKt/vyDvQ288wSvYmNP7SFxTDr3bskCprO/xgZ0WsljAR10ogtJZDiUogvuVM4cDR+uCzwftXUN8QeIywIeaYiEGxjhSgvSYorkgqsOL+Wu2nf9Lgje/LI5ne/HhWRqe/3KDbHXYg20/zbwzQIuvP7iA3UkzyyJkZD8/1BjoS2Wo+cIO8TMsgnhgAH3F0K0jOtJXctRORnRn1cBXWj5X79XgkrTOnA2OVLUNAQ3XbEv9hmtX/k5EwSgcjZFTbwLE10uGvjY= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Dec 17, 2024 at 06:26:26PM -0800, Luis Chamberlain wrote: > Now that we can read asynchronously buffer heads from a folio in > chunks, we can chop up bh_read_iter() with a smaller array size. > Use an array of 8 to avoid stack growth warnings on systems with > huge base page sizes. > > Reviewed-by: Hannes Reinecke > Signed-off-by: Luis Chamberlain > --- > fs/buffer.c | 15 ++++++++++----- > 1 file changed, 10 insertions(+), 5 deletions(-) > > diff --git a/fs/buffer.c b/fs/buffer.c > index b8ba72f2f211..bfa9c09b8597 100644 > --- a/fs/buffer.c > +++ b/fs/buffer.c > @@ -2415,7 +2415,10 @@ static void bh_read_batch_async(struct folio *folio, > (__tmp); \ > (__tmp) = bh_next(__tmp, __head)) > > +#define MAX_BUF_CHUNK 8 > + > struct bh_iter { > + int chunk_number; > sector_t iblock; > get_block_t *get_block; > bool any_get_block_error; Oh... this can be cleaned up even further, chunk_idx and be removed now, and we can also remove the unused i variable... I'll wait for more feedback for a v2. Luis