shmem: move memcg charge out of shmem_add_to_page_cache()

Extract shmem's memcg charging out of shmem_add_to_page_cache(): it's
misleading done there, because many calls are dealing with a swapcache
page, whose memcg is nowadays always remembered while swapped out, then
the charge re-levied when it's brought back into swapcache.

Temporarily move it back up to the shmem_get_folio_gfp() level, where the
memcg was charged before v5.8; but the next commit goes on to move it back
down to a new home.

In making this change, it becomes clear that shmem_swapin_folio() does not
need to know the vma, just the fault mm (if any): call it fault_mm rather
than charge_mm - let mem_cgroup_charge() decide whom to charge.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Hugh Dickins <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Cc: Axel Rasmussen <[email protected]>
Cc: Carlos Maiolino <[email protected]>
Cc: Christian Brauner <[email protected]>
Cc: Chuck Lever <[email protected]>
Cc: Darrick J. Wong <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Tim Chen <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions