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linux-next/Documentation/mm
Fabio M. De Francesco 516ea046ec Documentation/mm: don't kmap*() pages which can't come from HIGHMEM
There is no need to kmap*() pages which are guaranteed to come from
ZONE_NORMAL (or lower).  Linux has currently several call sites of
kmap{,_atomic,_local_page}() on pages which are clearly known which can't
come from ZONE_HIGHMEM.

Therefore, add a paragraph to highmem.rst, to explain better that a plain
page_address() may be used for getting the address of pages which cannot
come from ZONE_HIGHMEM, although it is always safe to use
kmap_local_page() / kunmap_local() also on those pages.

Link: https://lkml.kernel.org/r/20220728154844.10874-4-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-08-08 18:06:45 -07:00
..
damon
active_mm.rst
arch_pgtable_helpers.rst
balance.rst
bootmem.rst
free_page_reporting.rst
frontswap.rst
highmem.rst Documentation/mm: don't kmap*() pages which can't come from HIGHMEM 2022-08-08 18:06:45 -07:00
hmm.rst
hugetlbfs_reserv.rst
hwpoison.rst
index.rst
ksm.rst
memory-model.rst
mmu_notifier.rst
numa.rst
oom.rst
overcommit-accounting.rst
page_allocation.rst
page_cache.rst
page_frags.rst
page_migration.rst
page_owner.rst
page_reclaim.rst
page_table_check.rst
page_tables.rst
physical_memory.rst
process_addrs.rst
remap_file_pages.rst
shmfs.rst
slab.rst
slub.rst
split_page_table_lock.rst
swap.rst
transhuge.rst
unevictable-lru.rst
vmalloc.rst
vmalloced-kernel-stacks.rst
vmemmap_dedup.rst mm: hugetlb_vmemmap: move code comments to vmemmap_dedup.rst 2022-08-08 18:06:43 -07:00
z3fold.rst
zsmalloc.rst