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authorPasha Tatashin <pasha.tatashin@soleen.com>2023-01-13 18:42:53 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-02-03 09:33:11 +0300
commit6189eb82f0aec8a877190bf52e629c687ed02773 (patch)
tree3eb6efd413832ef68f72750f89c7e327f71c1a99 /mm/page_table_check.c
parent950fe885a89770619e315f9b46301eebf0aab7b3 (diff)
downloadlinux-6189eb82f0aec8a877190bf52e629c687ed02773.tar.xz
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.c1
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)