Re: [PATCH v7 03/11] filemap: allocate mapping_min_order folios in the page cache

[Hannes Reinecke]

On 6/7/24 16:58, Pankaj Raghav (Samsung) wrote:
> From: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
>
> 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 <mcgrof@xxxxxxxxxx>
> Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
> Signed-off-by: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
> ---
>   include/linux/pagemap.h | 20 ++++++++++++++++++++
>   mm/filemap.c            | 26 ++++++++++++++++++--------
>   2 files changed, 38 insertions(+), 8 deletions(-)
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>

Cheers,

Hannes
--
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@xxxxxxx                                +49 911 74053 688
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