diff options
| author |   Peter Xu <peterx@redhat.com> | 2022-08-11 12:13:31 -0400 |
|---|---|---|
| committer |   Andrew Morton <akpm@linux-foundation.org> | 2022-09-26 19:46:05 -0700 |
| commit | 5154e607967d3f587fda84a40abbf900275016c9 (patch) | |
| tree | 883f14728fbb9373e092f4e3345f5537dade7962 /include/linux | |
| parent | mm/swap: cache maximum swapfile size when init swap (diff) | |
| download | linux-dev-5154e607967d3f587fda84a40abbf900275016c9.tar.xz linux-dev-5154e607967d3f587fda84a40abbf900275016c9.zip | |
mm/swap: cache swap migration A/D bits support
Introduce a variable swap_migration_ad_supported to cache whether the arch
supports swap migration A/D bits.
Here one thing to mention is that SWP_MIG_TOTAL_BITS will internally
reference the other macro MAX_PHYSMEM_BITS, which is a function call on
x86 (constant on all the rest of archs).
It's safe to reference it in swapfile_init() because when reaching here
we're already during initcalls level 4 so we must have initialized 5-level
pgtable for x86_64 (right after early_identify_cpu() finishes).
- start_kernel
- setup_arch
- early_cpu_init
- get_cpu_cap --> fetch from CPUID (including X86_FEATURE_LA57)
- early_identify_cpu --> clear X86_FEATURE_LA57 (if early lvl5 not enabled (USE_EARLY_PGTABLE_L5))
- arch_call_rest_init
- rest_init
- kernel_init
- kernel_init_freeable
- do_basic_setup
- do_initcalls --> calls swapfile_init() (initcall level 4)
This should slightly speed up the migration swap entry handlings.
Link: https://lkml.kernel.org/r/20220811161331.37055-8-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/swapfile.h | 2 | ||||
| -rw-r--r-- | include/linux/swapops.h | 7 |
2 files changed, 3 insertions, 6 deletions
diff --git a/include/linux/swapfile.h b/include/linux/swapfile.h index e2d11ae4e73d..7ed529a77c5b 100644 --- a/include/linux/swapfile.h +++ b/include/linux/swapfile.h @@ -12,5 +12,7 @@ unsigned long arch_max_swapfile_size(void); /* Maximum swapfile size supported for the arch (not inclusive). */ extern unsigned long swapfile_maximum_size; +/* Whether swap migration entry supports storing A/D bits for the arch */ +extern bool swap_migration_ad_supported; #endif /* _LINUX_SWAPFILE_H */ diff --git a/include/linux/swapops.h b/include/linux/swapops.h index 027b4095e132..86b95ccb81bb 100644 --- a/include/linux/swapops.h +++ b/include/linux/swapops.h @@ -301,13 +301,8 @@ static inline swp_entry_t make_writable_migration_entry(pgoff_t offset) */ static inline bool migration_entry_supports_ad(void) { - /* - * max_swapfile_size() returns the max supported swp-offset plus 1. - * We can support the migration A/D bits iff the pfn swap entry has - * the offset large enough to cover all of them (PFN, A & D bits). - */ #ifdef CONFIG_SWAP - return swapfile_maximum_size >= (1UL << SWP_MIG_TOTAL_BITS); + return swap_migration_ad_supported; #else /* CONFIG_SWAP */ return false; #endif /* CONFIG_SWAP */ |