git/linux-cryptodev-2.6
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git synced 2026-04-23 05:56:14 -04:00
Code Issues Packages Projects Releases Wiki Activity

mm/page_ext: do not allocate space for page_ext->flags if not needed

Browse Source 
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>
This commit is contained in:
Pasha Tatashin
2023-01-13 15:42:53 +00:00
committed by Andrew Morton
parent 950fe885a8
commit 6189eb82f0
4 changed files with 32 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
include/linux/page_ext.h
View File

@@ -7,15 +7,33 @@
#include <linux/stackdepot.h>
struct pglist_data;
/**
* struct page_ext_operations - per page_ext client operations
* @offset: Offset to the client's data within page_ext. Offset is returned to
* the client by page_ext_init.
* @size: The size of the client data within page_ext.
* @need: Function that returns true if client requires page_ext.
* @init: (optional) Called to initialize client once page_exts are allocated.
* @need_shared_flags: True when client is using shared page_ext->flags
* field.
*
* Each Page Extension client must define page_ext_operations in
* page_ext_ops array.
*/
struct page_ext_operations {
size_t offset;
size_t size;
bool (*need)(void);
void (*init)(void);
bool need_shared_flags;
};
#ifdef CONFIG_PAGE_EXTENSION
/*
* The page_ext_flags users must set need_shared_flags to true.
*/
enum page_ext_flags {
PAGE_EXT_OWNER,
PAGE_EXT_OWNER_ALLOCATED,