linux/mm
Fabio M. De Francesco f7ef5fe74a mm/memory: replace kmap() with kmap_local_page()
kmap() has been deprecated in favor of kmap_local_page().

Therefore, replace kmap() with kmap_local_page() in mm/memory.c.

There are two main problems with kmap(): (1) It comes with an overhead as
the mapping space is restricted and protected by a global lock for
synchronization and (2) it also requires global TLB invalidation when the
kmap's pool wraps and it might block when the mapping space is fully
utilized until a slot becomes available.

With kmap_local_page() the mappings are per thread, CPU local, can take
page-faults, and can be called from any context (including interrupts). 
It is faster than kmap() in kernels with HIGHMEM enabled.  The tasks can
be preempted and, when they are scheduled to run again, the kernel virtual
addresses are restored and still valid.

Obviously, thread locality implies that the kernel virtual addresses
returned by kmap_local_page() are only valid in the context of the callers
(i.e., they cannot be handed to other threads).

The use of kmap_local_page() in mm/memory.c does not break the
above-mentioned assumption, so it is allowed and preferred.

Link: https://lkml.kernel.org/r/20231215084417.2002370-1-fabio.maria.de.francesco@linux.intel.com
Link: https://lkml.kernel.org/r/20231214081039.1919328-1-fabio.maria.de.francesco@linux.intel.com
Signed-off-by: Fabio M. De Francesco <fabio.maria.de.francesco@linux.intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-20 14:48:14 -08:00
..
damon mm/damon/core-test: test max_nr_accesses overflow caused divide-by-zero 2023-12-20 14:48:13 -08:00
kasan sync mm-stable with mm-hotfixes-stable to pick up depended-upon changes 2023-12-20 14:47:18 -08:00
kfence LoongArch changes for v6.6 2023-09-08 12:16:52 -07:00
kmsan kmsan: use stack_depot_save instead of __stack_depot_save 2023-12-10 16:51:46 -08:00
backing-dev.c writeback: remove redundant checks for root memcg 2023-08-21 13:37:48 -07:00
balloon_compaction.c
bootmem_info.c bootmem: use kmemleak_free_part_phys in put_page_bootmem 2023-10-25 16:47:13 -07:00
cma.c mm: cma: remove unnecessary initialization of ret 2023-12-12 10:57:08 -08:00
cma.h
cma_debug.c
cma_sysfs.c mm: cma: make kobj_type structure constant 2023-03-28 16:20:06 -07:00
compaction.c mm: compaction: avoid fast_isolate_freepages blindly choose improper pageblock 2023-12-12 10:57:08 -08:00
debug.c mm: update validate_mm() to use vma iterator 2023-06-09 16:25:31 -07:00
debug_page_alloc.c mm: page_alloc: split out DEBUG_PAGEALLOC 2023-06-09 16:25:23 -07:00
debug_page_ref.c
debug_vm_pgtable.c mm: fix multiple typos in multiple files 2023-10-25 16:47:14 -07:00
dmapool.c dmapool: create/destroy cleanup 2023-06-09 16:25:17 -07:00
dmapool_test.c dmapool: add alloc/free performance test 2023-04-05 19:42:38 -07:00
early_ioremap.c mm/early_ioremap.c: improve the execution efficiency of early_ioremap_setup() 2023-06-09 16:25:56 -07:00
fadvise.c mm: remove unnecessary pagevec includes 2023-06-23 16:59:31 -07:00
fail_page_alloc.c mm: page_alloc: split out FAIL_PAGE_ALLOC 2023-06-09 16:25:23 -07:00
failslab.c mm: fix unexpected changes to {failslab|fail_page_alloc}.attr 2022-11-22 18:50:44 -08:00
filemap.c sync mm-stable with mm-hotfixes-stable to pick up depended-upon changes 2023-12-20 14:47:18 -08:00
folio-compat.c mm: return void from folio_start_writeback() and related functions 2023-12-10 16:51:37 -08:00
gup.c mm/gup: fix follow_devmap_p[mu]d() on page==NULL handling 2023-12-10 16:51:52 -08:00
gup_test.c Merge mm-hotfixes-stable into mm-stable to pick up depended-upon changes. 2023-06-23 16:58:19 -07:00
gup_test.h mm/gup_test: start/stop/read functionality for PIN LONGTERM test 2022-11-08 17:37:15 -08:00
highmem.c mm: ptep_get() conversion 2023-06-19 16:19:25 -07:00
hmm.c mm: enable page walking API to lock vmas during the walk 2023-08-21 13:07:20 -07:00
huge_memory.c mm: thp: introduce multi-size THP sysfs interface 2023-12-20 14:48:12 -08:00
hugetlb.c hugetlb: fix null-ptr-deref in hugetlb_vma_lock_write 2023-12-06 16:12:43 -08:00
hugetlb_cgroup.c mm, hugetlb: remove HUGETLB_CGROUP_MIN_ORDER 2023-10-18 14:34:17 -07:00
hugetlb_vmemmap.c mm: hugetlb_vmemmap: move mmap lock to vmemmap_remap_range() 2023-12-12 10:57:08 -08:00
hugetlb_vmemmap.h mm: hugetlb_vmemmap: fix reference to nonexistent file 2023-10-25 16:47:14 -07:00
hwpoison-inject.c
init-mm.c mm: move dummy_vm_ops out of a header 2023-08-21 13:37:46 -07:00
internal.h mm: use vma_pages() for vma objects 2023-12-12 10:57:08 -08:00
interval_tree.c
io-mapping.c
ioremap.c mm: ioremap: remove unneeded ioremap_allowed and iounmap_allowed 2023-08-18 10:12:36 -07:00
Kconfig mm/thp: add CONFIG_TRANSPARENT_HUGEPAGE_NEVER option 2023-12-12 10:57:07 -08:00
Kconfig.debug mm: page_table_check: Make it dependent on EXCLUSIVE_SYSTEM_RAM 2023-05-29 16:14:28 +01:00
khugepaged.c mm: thp: introduce multi-size THP sysfs interface 2023-12-20 14:48:12 -08:00
kmemleak.c kmemleak: avoid RCU stalls when freeing metadata for per-CPU pointers 2023-12-12 10:57:07 -08:00
ksm.c mm: ksm: remove unnecessary try_to_freeze() 2023-12-20 14:48:13 -08:00
list_lru.c mm/list_lru.c: remove unused list_lru_from_kmem() 2023-12-20 14:48:11 -08:00
maccess.c mm: Fix copy_from_user_nofault(). 2023-04-12 17:36:23 -07:00
madvise.c mm/madvise: add cond_resched() in madvise_cold_or_pageout_pte_range() 2023-12-06 16:12:50 -08:00
Makefile mm: vmscan: move shrinker-related code into a separate file 2023-10-04 10:32:23 -07:00
mapping_dirty_helpers.c mm: fix clean_record_shared_mapping_range kernel-doc 2023-08-24 16:20:30 -07:00
memblock.c NUMA: optimize detection of memory with no node id assigned by firmware 2023-12-10 16:51:34 -08:00
memcontrol.c mm: memcg: restore subtree stats flushing 2023-12-20 14:48:11 -08:00
memfd.c memfd: drop warning for missing exec-related flags 2023-10-04 10:32:22 -07:00
memory-failure.c sync mm-stable with mm-hotfixes-stable to pick up depended-upon changes 2023-12-20 14:47:18 -08:00
memory-tiers.c dax, kmem: calculate abstract distance with general interface 2023-10-16 15:44:39 -07:00
memory.c mm/memory: replace kmap() with kmap_local_page() 2023-12-20 14:48:14 -08:00
memory_hotplug.c mm/memory_hotplug: split memmap_on_memory requests across memblocks 2023-12-10 16:51:34 -08:00
mempolicy.c Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
mempool.c mm/mempool: replace kmap_atomic() with kmap_local_page() 2023-12-10 16:51:49 -08:00
memremap.c mm: use vmem_altmap code without CONFIG_ZONE_DEVICE 2023-12-10 16:51:48 -08:00
memtest.c mm: memtest: convert to memtest_report_meminfo() 2023-08-21 13:37:47 -07:00
migrate.c mm: migrate high-order folios in swap cache correctly 2023-12-20 13:46:19 -08:00
migrate_device.c Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
mincore.c mm: enable page walking API to lock vmas during the walk 2023-08-21 13:07:20 -07:00
mlock.c mm: mlock: avoid folio_within_range() on KSM pages 2023-10-25 16:47:14 -07:00
mm_init.c mm/mm_init.c: append newline to the unavailable ranges log-message 2023-12-10 16:51:51 -08:00
mm_slot.h
mmap.c mmap: remove the IA64-specific vma expansion implementation 2023-12-10 16:51:39 -08:00
mmap_lock.c
mmu_gather.c mm: fix kernel-doc warning from tlb_flush_rmaps() 2023-08-24 16:20:30 -07:00
mmu_notifier.c mmu_notifiers: rename invalidate_range notifier 2023-08-18 10:12:41 -07:00
mmzone.c zswap: shrink zswap pool based on memory pressure 2023-12-12 10:57:02 -08:00
mprotect.c mm: mprotect: use a folio in change_pte_range() 2023-10-25 16:47:12 -07:00
mremap.c mm: abstract VMA merge and extend into vma_merge_extend() helper 2023-10-18 14:34:18 -07:00
msync.c
nommu.c Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
oom_kill.c mm, oom:dump_tasks add rss detailed information printing 2023-12-10 16:51:53 -08:00
page-writeback.c mm: return void from folio_start_writeback() and related functions 2023-12-10 16:51:37 -08:00
page_alloc.c mm: page_alloc: unreserve highatomic page blocks before oom 2023-12-10 16:51:52 -08:00
page_counter.c
page_ext.c mm/page_ext: move functions around for minor cleanups to page_ext 2023-08-18 10:12:31 -07:00
page_idle.c mm: page_idle: convert page idle to use a folio 2023-01-18 17:12:52 -08:00
page_io.c mm: memcg: add THP swap out info for anonymous reclaim 2023-10-04 10:32:27 -07:00
page_isolation.c mm/hugetlb: get rid of page_hstate() 2023-08-18 10:12:39 -07:00
page_owner.c mm/page_owner: record and dump free_pid and free_tgid 2023-12-10 16:51:40 -08:00
page_poison.c mm/page_poison: replace kmap_atomic() with kmap_local_page() 2023-12-10 16:51:50 -08:00
page_reporting.c mm, treewide: redefine MAX_ORDER sanely 2023-04-05 19:42:46 -07:00
page_reporting.h
page_table_check.c mm: convert page_table_check_pte_set() to page_table_check_ptes_set() 2023-08-24 16:20:18 -07:00
page_vma_mapped.c mm: thp: introduce multi-size THP sysfs interface 2023-12-20 14:48:12 -08:00
pagewalk.c mm: pagewalk: assert write mmap lock only for walking the user page tables 2023-12-10 16:51:53 -08:00
percpu-internal.h percpu-internal/pcpu_chunk: re-layout pcpu_chunk structure to reduce false sharing 2023-06-19 16:19:29 -07:00
percpu-km.c
percpu-stats.c
percpu-vm.c
percpu.c Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
pgalloc-track.h
pgtable-generic.c mm/pgtable: notes on pte_offset_map[_lock]() 2023-08-18 10:12:25 -07:00
process_vm_access.c mm: fix process_vm_rw page counts 2023-12-10 16:51:39 -08:00
ptdump.c mm: ptdump should use ptep_get_lockless() 2023-06-19 16:19:24 -07:00
readahead.c mm/readahead: do not allow order-1 folio 2023-12-12 10:57:06 -08:00
rmap.c mm: non-pmd-mappable, large folios for folio_add_new_anon_rmap() 2023-12-20 14:48:12 -08:00
rodata_test.c
secretmem.c mm/secretmem: use a folio in secretmem_fault() 2023-08-21 13:38:02 -07:00
shmem.c sync mm-stable with mm-hotfixes-stable to pick up depended-upon changes 2023-12-20 14:47:18 -08:00
shmem_quota.c shmem: Add default quota limit mount options 2023-08-09 09:15:40 +02:00
show_mem.c mm: refactor si_mem_available() 2023-10-04 10:32:19 -07:00
shrinker.c mm: shrinker: convert shrinker_rwsem to mutex 2023-10-04 10:32:26 -07:00
shrinker_debug.c mm: shrinker: convert shrinker_rwsem to mutex 2023-10-04 10:32:26 -07:00
shuffle.c mm/shuffle: convert module_param_call to module_param_cb 2022-10-03 14:03:07 -07:00
shuffle.h mm, treewide: redefine MAX_ORDER sanely 2023-04-05 19:42:46 -07:00
slab.c Randomized slab caches for kmalloc() 2023-07-18 10:07:47 +02:00
slab.h mm: kmem: scoped objcg protection 2023-10-25 16:47:11 -07:00
slab_common.c RCU pull request for v6.7 2023-10-30 18:01:41 -10:00
slub.c slub, kasan: improve interaction of KASAN and slub_debug poisoning 2023-12-10 16:51:48 -08:00
sparse-vmemmap.c mm/vmemmap: allow architectures to override how vmemmap optimization works 2023-08-18 10:12:53 -07:00
sparse.c mm/sparse: remove redundant judgments from macro for_each_present_section_nr 2023-08-18 10:12:14 -07:00
swap.c mm: remove references to pagevec 2023-06-23 16:59:30 -07:00
swap.h zswap: make shrinking memcg-aware 2023-12-12 10:57:01 -08:00
swap_cgroup.c mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled 2022-10-03 14:03:36 -07:00
swap_slots.c
swap_state.c zswap: shrink zswap pool based on memory pressure 2023-12-12 10:57:02 -08:00
swapfile.c mm/swapfile: replace kmap_atomic() with kmap_local_page() 2023-12-10 16:51:53 -08:00
truncate.c fs: convert error_remove_page to error_remove_folio 2023-12-10 16:51:42 -08:00
usercopy.c mm: Fix copy_from_user_nofault(). 2023-04-12 17:36:23 -07:00
userfaultfd.c mm: more ptep_get() conversion 2023-11-15 15:30:09 -08:00
util.c mm/util: use kmap_local_page() in memcmp_pages() 2023-12-10 16:51:49 -08:00
vmalloc.c mm/vmalloc: fix the unchecked dereference warning in vread_iter() 2023-11-01 12:38:35 -07:00
vmpressure.c net-memcg: Fix scope of sockmem pressure indicators 2023-08-16 12:21:32 +01:00
vmscan.c mm: memcg: restore subtree stats flushing 2023-12-20 14:48:11 -08:00
vmstat.c mm: memcg: add per-memcg zswap writeback stat 2023-12-12 10:57:02 -08:00
workingset.c mm: memcg: restore subtree stats flushing 2023-12-20 14:48:11 -08:00
z3fold.c mm/z3fold: remove obsolete comment for struct z3fold_pool 2023-08-21 13:37:51 -07:00
zbud.c mm: zswap: remove shrink from zpool interface 2023-06-19 16:19:27 -07:00
zpool.c mm: zswap: remove shrink from zpool interface 2023-06-19 16:19:27 -07:00
zsmalloc.c zsmalloc: use copy_page for full page copy 2023-10-18 14:34:16 -07:00
zswap.c mm: memcg: restore subtree stats flushing 2023-12-20 14:48:11 -08:00