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| author | Pasha Tatashin <pasha.tatashin@soleen.com> | 2023-01-13 15:42:53 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-02-02 22:33:11 -0800 |
| commit | 6189eb82f0aec8a877190bf52e629c687ed02773 (patch) | |
| tree | 3eb6efd413832ef68f72750f89c7e327f71c1a99 /mm/page_table_check.c | |
| parent | 950fe885a89770619e315f9b46301eebf0aab7b3 (diff) | |
| download | linux-stable-6189eb82f0aec8a877190bf52e629c687ed02773.tar.gz linux-stable-6189eb82f0aec8a877190bf52e629c687ed02773.tar.bz2 linux-stable-6189eb82f0aec8a877190bf52e629c687ed02773.zip | |
mm/page_ext: do not allocate space for page_ext->flags if not needed
There is 8 byte page_ext->flags field allocated per page whenever
CONFIG_PAGE_EXTENSION is enabled. However, not every user of page_ext
uses flags. Therefore, check whether flags is needed at least by one user
and if so allocate space for it.
For example when page_table_check is enabled, on a machine with 128G
of memory before the fix:
[ 2.244288] allocated 536870912 bytes of page_ext
after the fix:
[ 2.160154] allocated 268435456 bytes of page_ext
Also, add a kernel-doc comment before page_ext_operations that describes
the fields, and remove check if need() is set, as that is now a required
field.
[pasha.tatashin@soleen.com: address comments from Mike Rapoport]
Link: https://lkml.kernel.org/r/20230117202103.1412449-1-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20230113154253.92480-1-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Charan Teja Kalla <quic_charante@quicinc.com>
Cc: Li Zhe <lizhe.67@bytedance.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/page_table_check.c')
| -rw-r--r-- | mm/page_table_check.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/page_table_check.c b/mm/page_table_check.c index 93e633c1d587..25d8610c0042 100644 --- a/mm/page_table_check.c +++ b/mm/page_table_check.c @@ -45,6 +45,7 @@ struct page_ext_operations page_table_check_ops = { .size = sizeof(struct page_table_check), .need = need_page_table_check, .init = init_page_table_check, + .need_shared_flags = false, }; static struct page_table_check *get_page_table_check(struct page_ext *page_ext) |