diff options
author | Roman Gushchin <guro@fb.com> | 2020-12-01 22:58:30 +0100 |
---|---|---|
committer | Alexei Starovoitov <ast@kernel.org> | 2020-12-03 03:28:06 +0100 |
commit | 18b2db3b0385226b71cb3288474fa5a6e4a45474 (patch) | |
tree | f828f2be8490785b26406010cbbd86e025ba5a4a /kernel/latencytop.c | |
parent | mm: Introduce page memcg flags (diff) | |
download | linux-18b2db3b0385226b71cb3288474fa5a6e4a45474.tar.xz linux-18b2db3b0385226b71cb3288474fa5a6e4a45474.zip |
mm: Convert page kmemcg type to a page memcg flag
PageKmemcg flag is currently defined as a page type (like buddy, offline,
table and guard). Semantically it means that the page was accounted as a
kernel memory by the page allocator and has to be uncharged on the
release.
As a side effect of defining the flag as a page type, the accounted page
can't be mapped to userspace (look at page_has_type() and comments above).
In particular, this blocks the accounting of vmalloc-backed memory used
by some bpf maps, because these maps do map the memory to userspace.
One option is to fix it by complicating the access to page->mapcount,
which provides some free bits for page->page_type.
But it's way better to move this flag into page->memcg_data flags.
Indeed, the flag makes no sense without enabled memory cgroups and memory
cgroup pointer set in particular.
This commit replaces PageKmemcg() and __SetPageKmemcg() with
PageMemcgKmem() and an open-coded OR operation setting the memcg pointer
with the MEMCG_DATA_KMEM bit. __ClearPageKmemcg() can be simple deleted,
as the whole memcg_data is zeroed at once.
As a bonus, on !CONFIG_MEMCG build the PageMemcgKmem() check will be
compiled out.
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Link: https://lkml.kernel.org/r/20201027001657.3398190-5-guro@fb.com
Link: https://lore.kernel.org/bpf/20201201215900.3569844-5-guro@fb.com
Diffstat (limited to 'kernel/latencytop.c')
0 files changed, 0 insertions, 0 deletions