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| 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 /mm/swapfile.c | |
| parent | be45a4902c7caa717fee6b2f671e59b396ed395c (diff) | |
| download | linux-5154e607967d3f587fda84a40abbf900275016c9.tar.gz linux-5154e607967d3f587fda84a40abbf900275016c9.tar.bz2 linux-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 'mm/swapfile.c')
| -rw-r--r-- | mm/swapfile.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c index 3cc64399df44..263b19e693cf 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -64,6 +64,9 @@ EXPORT_SYMBOL_GPL(nr_swap_pages); long total_swap_pages; static int least_priority = -1; unsigned long swapfile_maximum_size; +#ifdef CONFIG_MIGRATION +bool swap_migration_ad_supported; +#endif /* CONFIG_MIGRATION */ static const char Bad_file[] = "Bad swap file entry "; static const char Unused_file[] = "Unused swap file entry "; @@ -3680,6 +3683,11 @@ static int __init swapfile_init(void) swapfile_maximum_size = arch_max_swapfile_size(); +#ifdef CONFIG_MIGRATION + if (swapfile_maximum_size >= (1UL << SWP_MIG_TOTAL_BITS)) + swap_migration_ad_supported = true; +#endif /* CONFIG_MIGRATION */ + return 0; } subsys_initcall(swapfile_init); |