diff options
Diffstat (limited to 'Documentation/vm')
| -rw-r--r-- | Documentation/vm/arch_pgtable_helpers.rst | 258 | ||||
| -rw-r--r-- | Documentation/vm/memory-model.rst | 9 | ||||
| -rw-r--r-- | Documentation/vm/slub.rst | 37 |
3 files changed, 290 insertions, 14 deletions
diff --git a/Documentation/vm/arch_pgtable_helpers.rst b/Documentation/vm/arch_pgtable_helpers.rst new file mode 100644 index 000000000000..f3591ee3aaa8 --- /dev/null +++ b/Documentation/vm/arch_pgtable_helpers.rst @@ -0,0 +1,258 @@ +.. SPDX-License-Identifier: GPL-2.0 + +.. _arch_page_table_helpers: + +=============================== +Architecture Page Table Helpers +=============================== + +Generic MM expects architectures (with MMU) to provide helpers to create, access +and modify page table entries at various level for different memory functions. +These page table helpers need to conform to a common semantics across platforms. +Following tables describe the expected semantics which can also be tested during +boot via CONFIG_DEBUG_VM_PGTABLE option. All future changes in here or the debug +test need to be in sync. + +====================== +PTE Page Table Helpers +====================== + ++---------------------------+--------------------------------------------------+ +| pte_same | Tests whether both PTE entries are the same | ++---------------------------+--------------------------------------------------+ +| pte_bad | Tests a non-table mapped PTE | ++---------------------------+--------------------------------------------------+ +| pte_present | Tests a valid mapped PTE | ++---------------------------+--------------------------------------------------+ +| pte_young | Tests a young PTE | ++---------------------------+--------------------------------------------------+ +| pte_dirty | Tests a dirty PTE | ++---------------------------+--------------------------------------------------+ +| pte_write | Tests a writable PTE | ++---------------------------+--------------------------------------------------+ +| pte_special | Tests a special PTE | ++---------------------------+--------------------------------------------------+ +| pte_protnone | Tests a PROT_NONE PTE | ++---------------------------+--------------------------------------------------+ +| pte_devmap | Tests a ZONE_DEVICE mapped PTE | ++---------------------------+--------------------------------------------------+ +| pte_soft_dirty | Tests a soft dirty PTE | ++---------------------------+--------------------------------------------------+ +| pte_swp_soft_dirty | Tests a soft dirty swapped PTE | ++---------------------------+--------------------------------------------------+ +| pte_mkyoung | Creates a young PTE | ++---------------------------+--------------------------------------------------+ +| pte_mkold | Creates an old PTE | ++---------------------------+--------------------------------------------------+ +| pte_mkdirty | Creates a dirty PTE | ++---------------------------+--------------------------------------------------+ +| pte_mkclean | Creates a clean PTE | ++---------------------------+--------------------------------------------------+ +| pte_mkwrite | Creates a writable PTE | ++---------------------------+--------------------------------------------------+ +| pte_mkwrprotect | Creates a write protected PTE | ++---------------------------+--------------------------------------------------+ +| pte_mkspecial | Creates a special PTE | ++---------------------------+--------------------------------------------------+ +| pte_mkdevmap | Creates a ZONE_DEVICE mapped PTE | ++---------------------------+--------------------------------------------------+ +| pte_mksoft_dirty | Creates a soft dirty PTE | ++---------------------------+--------------------------------------------------+ +| pte_clear_soft_dirty | Clears a soft dirty PTE | ++---------------------------+--------------------------------------------------+ +| pte_swp_mksoft_dirty | Creates a soft dirty swapped PTE | ++---------------------------+--------------------------------------------------+ +| pte_swp_clear_soft_dirty | Clears a soft dirty swapped PTE | ++---------------------------+--------------------------------------------------+ +| pte_mknotpresent | Invalidates a mapped PTE | ++---------------------------+--------------------------------------------------+ +| ptep_get_and_clear | Clears a PTE | ++---------------------------+--------------------------------------------------+ +| ptep_get_and_clear_full | Clears a PTE | ++---------------------------+--------------------------------------------------+ +| ptep_test_and_clear_young | Clears young from a PTE | ++---------------------------+--------------------------------------------------+ +| ptep_set_wrprotect | Converts into a write protected PTE | ++---------------------------+--------------------------------------------------+ +| ptep_set_access_flags | Converts into a more permissive PTE | ++---------------------------+--------------------------------------------------+ + +====================== +PMD Page Table Helpers +====================== + ++---------------------------+--------------------------------------------------+ +| pmd_same | Tests whether both PMD entries are the same | ++---------------------------+--------------------------------------------------+ +| pmd_bad | Tests a non-table mapped PMD | ++---------------------------+--------------------------------------------------+ +| pmd_leaf | Tests a leaf mapped PMD | ++---------------------------+--------------------------------------------------+ +| pmd_huge | Tests a HugeTLB mapped PMD | ++---------------------------+--------------------------------------------------+ +| pmd_trans_huge | Tests a Transparent Huge Page (THP) at PMD | ++---------------------------+--------------------------------------------------+ +| pmd_present | Tests a valid mapped PMD | ++---------------------------+--------------------------------------------------+ +| pmd_young | Tests a young PMD | ++---------------------------+--------------------------------------------------+ +| pmd_dirty | Tests a dirty PMD | ++---------------------------+--------------------------------------------------+ +| pmd_write | Tests a writable PMD | ++---------------------------+--------------------------------------------------+ +| pmd_special | Tests a special PMD | ++---------------------------+--------------------------------------------------+ +| pmd_protnone | Tests a PROT_NONE PMD | ++---------------------------+--------------------------------------------------+ +| pmd_devmap | Tests a ZONE_DEVICE mapped PMD | ++---------------------------+--------------------------------------------------+ +| pmd_soft_dirty | Tests a soft dirty PMD | ++---------------------------+--------------------------------------------------+ +| pmd_swp_soft_dirty | Tests a soft dirty swapped PMD | ++---------------------------+--------------------------------------------------+ +| pmd_mkyoung | Creates a young PMD | ++---------------------------+--------------------------------------------------+ +| pmd_mkold | Creates an old PMD | ++---------------------------+--------------------------------------------------+ +| pmd_mkdirty | Creates a dirty PMD | ++---------------------------+--------------------------------------------------+ +| pmd_mkclean | Creates a clean PMD | ++---------------------------+--------------------------------------------------+ +| pmd_mkwrite | Creates a writable PMD | ++---------------------------+--------------------------------------------------+ +| pmd_mkwrprotect | Creates a write protected PMD | ++---------------------------+--------------------------------------------------+ +| pmd_mkspecial | Creates a special PMD | ++---------------------------+--------------------------------------------------+ +| pmd_mkdevmap | Creates a ZONE_DEVICE mapped PMD | ++---------------------------+--------------------------------------------------+ +| pmd_mksoft_dirty | Creates a soft dirty PMD | ++---------------------------+--------------------------------------------------+ +| pmd_clear_soft_dirty | Clears a soft dirty PMD | ++---------------------------+--------------------------------------------------+ +| pmd_swp_mksoft_dirty | Creates a soft dirty swapped PMD | ++---------------------------+--------------------------------------------------+ +| pmd_swp_clear_soft_dirty | Clears a soft dirty swapped PMD | ++---------------------------+--------------------------------------------------+ +| pmd_mkinvalid | Invalidates a mapped PMD [1] | ++---------------------------+--------------------------------------------------+ +| pmd_set_huge | Creates a PMD huge mapping | ++---------------------------+--------------------------------------------------+ +| pmd_clear_huge | Clears a PMD huge mapping | ++---------------------------+--------------------------------------------------+ +| pmdp_get_and_clear | Clears a PMD | ++---------------------------+--------------------------------------------------+ +| pmdp_get_and_clear_full | Clears a PMD | ++---------------------------+--------------------------------------------------+ +| pmdp_test_and_clear_young | Clears young from a PMD | ++---------------------------+--------------------------------------------------+ +| pmdp_set_wrprotect | Converts into a write protected PMD | ++---------------------------+--------------------------------------------------+ +| pmdp_set_access_flags | Converts into a more permissive PMD | ++---------------------------+--------------------------------------------------+ + +====================== +PUD Page Table Helpers +====================== + ++---------------------------+--------------------------------------------------+ +| pud_same | Tests whether both PUD entries are the same | ++---------------------------+--------------------------------------------------+ +| pud_bad | Tests a non-table mapped PUD | ++---------------------------+--------------------------------------------------+ +| pud_leaf | Tests a leaf mapped PUD | ++---------------------------+--------------------------------------------------+ +| pud_huge | Tests a HugeTLB mapped PUD | ++---------------------------+--------------------------------------------------+ +| pud_trans_huge | Tests a Transparent Huge Page (THP) at PUD | ++---------------------------+--------------------------------------------------+ +| pud_present | Tests a valid mapped PUD | ++---------------------------+--------------------------------------------------+ +| pud_young | Tests a young PUD | ++---------------------------+--------------------------------------------------+ +| pud_dirty | Tests a dirty PUD | ++---------------------------+--------------------------------------------------+ +| pud_write | Tests a writable PUD | ++---------------------------+--------------------------------------------------+ +| pud_devmap | Tests a ZONE_DEVICE mapped PUD | ++---------------------------+--------------------------------------------------+ +| pud_mkyoung | Creates a young PUD | ++---------------------------+--------------------------------------------------+ +| pud_mkold | Creates an old PUD | ++---------------------------+--------------------------------------------------+ +| pud_mkdirty | Creates a dirty PUD | ++---------------------------+--------------------------------------------------+ +| pud_mkclean | Creates a clean PUD | ++---------------------------+--------------------------------------------------+ +| pud_mkwrite | Creates a writable PUD | ++---------------------------+--------------------------------------------------+ +| pud_mkwrprotect | Creates a write protected PUD | ++---------------------------+--------------------------------------------------+ +| pud_mkdevmap | Creates a ZONE_DEVICE mapped PUD | ++---------------------------+--------------------------------------------------+ +| pud_mkinvalid | Invalidates a mapped PUD [1] | ++---------------------------+--------------------------------------------------+ +| pud_set_huge | Creates a PUD huge mapping | ++---------------------------+--------------------------------------------------+ +| pud_clear_huge | Clears a PUD huge mapping | ++---------------------------+--------------------------------------------------+ +| pudp_get_and_clear | Clears a PUD | ++---------------------------+--------------------------------------------------+ +| pudp_get_and_clear_full | Clears a PUD | ++---------------------------+--------------------------------------------------+ +| pudp_test_and_clear_young | Clears young from a PUD | ++---------------------------+--------------------------------------------------+ +| pudp_set_wrprotect | Converts into a write protected PUD | ++---------------------------+--------------------------------------------------+ +| pudp_set_access_flags | Converts into a more permissive PUD | ++---------------------------+--------------------------------------------------+ + +========================== +HugeTLB Page Table Helpers +========================== + ++---------------------------+--------------------------------------------------+ +| pte_huge | Tests a HugeTLB | ++---------------------------+--------------------------------------------------+ +| pte_mkhuge | Creates a HugeTLB | ++---------------------------+--------------------------------------------------+ +| huge_pte_dirty | Tests a dirty HugeTLB | ++---------------------------+--------------------------------------------------+ +| huge_pte_write | Tests a writable HugeTLB | ++---------------------------+--------------------------------------------------+ +| huge_pte_mkdirty | Creates a dirty HugeTLB | ++---------------------------+--------------------------------------------------+ +| huge_pte_mkwrite | Creates a writable HugeTLB | ++---------------------------+--------------------------------------------------+ +| huge_pte_mkwrprotect | Creates a write protected HugeTLB | ++---------------------------+--------------------------------------------------+ +| huge_ptep_get_and_clear | Clears a HugeTLB | ++---------------------------+--------------------------------------------------+ +| huge_ptep_set_wrprotect | Converts into a write protected HugeTLB | ++---------------------------+--------------------------------------------------+ +| huge_ptep_set_access_flags | Converts into a more permissive HugeTLB | ++---------------------------+--------------------------------------------------+ + +======================== +SWAP Page Table Helpers +======================== + ++---------------------------+--------------------------------------------------+ +| __pte_to_swp_entry | Creates a swapped entry (arch) from a mapped PTE | ++---------------------------+--------------------------------------------------+ +| __swp_to_pte_entry | Creates a mapped PTE from a swapped entry (arch) | ++---------------------------+--------------------------------------------------+ +| __pmd_to_swp_entry | Creates a swapped entry (arch) from a mapped PMD | ++---------------------------+--------------------------------------------------+ +| __swp_to_pmd_entry | Creates a mapped PMD from a swapped entry (arch) | ++---------------------------+--------------------------------------------------+ +| is_migration_entry | Tests a migration (read or write) swapped entry | ++---------------------------+--------------------------------------------------+ +| is_write_migration_entry | Tests a write migration swapped entry | ++---------------------------+--------------------------------------------------+ +| make_migration_entry_read | Converts into read migration swapped entry | ++---------------------------+--------------------------------------------------+ +| make_migration_entry | Creates a migration swapped entry (read or write)| ++---------------------------+--------------------------------------------------+ + +[1] https://lore.kernel.org/linux-mm/20181017020930.GN30832@redhat.com/ diff --git a/Documentation/vm/memory-model.rst b/Documentation/vm/memory-model.rst index cc65bc85d260..769449734573 100644 --- a/Documentation/vm/memory-model.rst +++ b/Documentation/vm/memory-model.rst @@ -141,11 +141,8 @@ sections: `mem_section` objects and the number of rows is calculated to fit all the memory sections. -The architecture setup code should call :c:func:`memory_present` for -each active memory range or use :c:func:`memblocks_present` or -:c:func:`sparse_memory_present_with_active_regions` wrappers to -initialize the memory sections. Next, the actual memory maps should be -set up using :c:func:`sparse_init`. +The architecture setup code should call sparse_init() to +initialize the memory sections and the memory maps. With SPARSEMEM there are two possible ways to convert a PFN to the corresponding `struct page` - a "classic sparse" and "sparse @@ -178,7 +175,7 @@ for persistent memory devices in pre-allocated storage on those devices. This storage is represented with :c:type:`struct vmem_altmap` that is eventually passed to vmemmap_populate() through a long chain of function calls. The vmemmap_populate() implementation may use the -`vmem_altmap` along with :c:func:`altmap_alloc_block_buf` helper to +`vmem_altmap` along with :c:func:`vmemmap_alloc_block_buf` helper to allocate memory map on the persistent memory device. ZONE_DEVICE diff --git a/Documentation/vm/slub.rst b/Documentation/vm/slub.rst index 4eee598555c9..289d231cee97 100644 --- a/Documentation/vm/slub.rst +++ b/Documentation/vm/slub.rst @@ -41,6 +41,11 @@ slub_debug=<Debug-Options>,<slab name1>,<slab name2>,... Enable options only for select slabs (no spaces after a comma) +Multiple blocks of options for all slabs or selected slabs can be given, with +blocks of options delimited by ';'. The last of "all slabs" blocks is applied +to all slabs except those that match one of the "select slabs" block. Options +of the first "select slabs" blocks that matches the slab's name are applied. + Possible debug options are:: F Sanity checks on (enables SLAB_DEBUG_CONSISTENCY_CHECKS @@ -83,17 +88,33 @@ switch off debugging for such caches by default, use:: slub_debug=O -In case you forgot to enable debugging on the kernel command line: It is -possible to enable debugging manually when the kernel is up. Look at the -contents of:: +You can apply different options to different list of slab names, using blocks +of options. This will enable red zoning for dentry and user tracking for +kmalloc. All other slabs will not get any debugging enabled:: + + slub_debug=Z,dentry;U,kmalloc-* + +You can also enable options (e.g. sanity checks and poisoning) for all caches +except some that are deemed too performance critical and don't need to be +debugged by specifying global debug options followed by a list of slab names +with "-" as options:: + + slub_debug=FZ;-,zs_handle,zspage + +The state of each debug option for a slab can be found in the respective files +under:: /sys/kernel/slab/<slab name>/ -Look at the writable files. Writing 1 to them will enable the -corresponding debug option. All options can be set on a slab that does -not contain objects. If the slab already contains objects then sanity checks -and tracing may only be enabled. The other options may cause the realignment -of objects. +If the file contains 1, the option is enabled, 0 means disabled. The debug +options from the ``slub_debug`` parameter translate to the following files:: + + F sanity_checks + Z red_zone + P poison + U store_user + T trace + A failslab Careful with tracing: It may spew out lots of information and never stop if used on the wrong slab. |