Linus Torvalds 574823bfab Change mincore() to count "mapped" pages rather than "cached" pages ... The semantics of what "in core" means for the mincore() system call are somewhat unclear, but Linux has always (since 2.3.52, which is when mincore() was initially done) treated it as "page is available in page cache" rather than "page is mapped in the mapping". The problem with that traditional semantic is that it exposes a lot of system cache state that it really probably shouldn't, and that users shouldn't really even care about. So let's try to avoid that information leak by simply changing the semantics to be that mincore() counts actual mapped pages, not pages that might be cheaply mapped if they were faulted (note the "might be" part of the old semantics: being in the cache doesn't actually guarantee that you can access them without IO anyway, since things like network filesystems may have to revalidate the cache before use). In many ways the old semantics were somewhat insane even aside from the information leak issue. From the very beginning (and that beginning is a long time ago: 2.3.52 was released in March 2000, I think), the code had a comment saying Later we can get more picky about what "in core" means precisely. and this is that "later". Admittedly it is much later than is really comfortable. NOTE! This is a real semantic change, and it is for example known to change the output of "fincore", since that program literally does a mmmap without populating it, and then doing "mincore()" on that mapping that doesn't actually have any pages in it. I'm hoping that nobody actually has any workflow that cares, and the info leak is real. We may have to do something different if it turns out that people have valid reasons to want the old semantics, and if we can limit the information leak sanely. Cc: Kevin Easton <kevin@guarana.org> Cc: Jiri Kosina <jikos@kernel.org> Cc: Masatake YAMATO <yamato@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2019-01-06 13:43:02 -08:00
..
kasan	mm: treewide: remove unused address argument from pte_alloc functions	2019-01-04 13:13:47 -08:00
backing-dev.c	blkcg: delay blkg destruction until after writeback has finished	2018-08-31 14:48:56 -06:00
balloon_compaction.c
cleancache.c	mm: use octal not symbolic permissions	2018-06-15 07:55:25 +09:00
cma.c	kasan, mm, arm64: tag non slab memory allocated via pagealloc	2018-12-28 12:11:44 -08:00
cma.h
cma_debug.c	mm/cma: remove unsupported gfp_mask parameter from cma_alloc()	2018-08-17 16:20:32 -07:00
compaction.c	mm: move zone watermark accesses behind an accessor	2018-12-28 12:11:48 -08:00
debug.c	mm/debug.c: make "migrate_reason_names[]" const char *	2018-12-28 12:11:48 -08:00
debug_page_ref.c
dmapool.c	mm: use octal not symbolic permissions	2018-06-15 07:55:25 +09:00
early_ioremap.c
fadvise.c	vfs: implement readahead(2) using POSIX_FADV_WILLNEED	2018-08-30 20:01:32 +02:00
failslab.c	mm: use octal not symbolic permissions	2018-06-15 07:55:25 +09:00
filemap.c	mm/: remove caller signal_pending branch predictions	2019-01-04 13:13:48 -08:00
frame_vector.c
frontswap.c	mm: use octal not symbolic permissions	2018-06-15 07:55:25 +09:00
gup.c	Merge branch 'akpm' (patches from Andrew)	2019-01-05 09:16:18 -08:00
gup_benchmark.c	mm/gup_benchmark.c: prevent integer overflow in ioctl	2018-10-31 08:54:12 -07:00
highmem.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
hmm.c	mm/hmm: fix memremap.h, move dev_page_fault_t callback to hmm	2018-12-28 12:11:52 -08:00
huge_memory.c	mm: treewide: remove unused address argument from pte_alloc functions	2019-01-04 13:13:47 -08:00
hugetlb.c	mm/: remove caller signal_pending branch predictions	2019-01-04 13:13:48 -08:00
hugetlb_cgroup.c
hwpoison-inject.c
init-mm.c	mm: Allocate the mm_cpumask (mm->cpu_bitmap[]) dynamically based on nr_cpu_ids	2018-07-17 09:35:30 +02:00
internal.h	mm: use alloc_flags to record if kswapd can wake	2018-12-28 12:11:48 -08:00
interval_tree.c
Kconfig	ksm: replace jhash2 with xxhash	2018-12-28 12:11:46 -08:00
Kconfig.debug	mm: clarify CONFIG_PAGE_POISONING and usage	2018-08-22 10:52:44 -07:00
khugepaged.c	mm/mmu_notifier: use structure for invalidate_range_start/end calls v2	2018-12-28 12:11:50 -08:00
kmemleak-test.c
kmemleak.c	kmemleak: add config to select auto scan	2018-12-28 12:11:51 -08:00
ksm.c	ksm: react on changing "sleep_millisecs" parameter faster	2018-12-28 12:11:51 -08:00
list_lru.c	mm/list_lru: introduce list_lru_shrink_walk_irq()	2018-08-17 16:20:32 -07:00
maccess.c	x86/fault: BUG() when uaccess helpers fault on kernel addresses	2018-09-03 15:12:09 +02:00
madvise.c	mm/mmu_notifier: use structure for invalidate_range_start/end calls v2	2018-12-28 12:11:50 -08:00
Makefile	mm: remove nobootmem	2018-10-31 08:54:16 -07:00
memblock.c	mm/memblock.c: skip kmemleak for kasan_init()	2018-12-28 12:11:49 -08:00
memcontrol.c	memcg, oom: notify on oom killer invocation from the charge path	2018-12-28 12:11:52 -08:00
memfd.c	memfd: Convert memfd_tag_pins to XArray	2018-10-21 10:46:41 -04:00
memory-failure.c	hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization	2018-12-28 12:11:51 -08:00
memory.c	mm: treewide: remove unused address argument from pte_alloc functions	2019-01-04 13:13:47 -08:00
memory_hotplug.c	mm, memory_hotplug: deobfuscate migration part of offlining	2018-12-28 12:11:50 -08:00
mempolicy.c	Revert "mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask"	2018-12-08 10:26:20 -08:00
mempool.c	mm/mempool.c: add missing parameter description	2018-08-22 10:52:44 -07:00
memtest.c
migrate.c	mm: treewide: remove unused address argument from pte_alloc functions	2019-01-04 13:13:47 -08:00
mincore.c	Change mincore() to count "mapped" pages rather than "cached" pages	2019-01-06 13:43:02 -08:00
mlock.c	dax: remove VM_MIXEDMAP for fsdax and device dax	2018-08-17 16:20:27 -07:00
mm_init.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
mmap.c	mm/mmap.c: remove verify_mm_writelocked()	2018-12-28 12:11:47 -08:00
mmu_context.c
mmu_gather.c	mm: Replace call_rcu_sched() with call_rcu()	2018-11-27 09:21:46 -08:00
mmu_notifier.c	mm/mmu_notifier: use structure for invalidate_range_start/end calls v2	2018-12-28 12:11:50 -08:00
mmzone.c
mprotect.c	mm/mmu_notifier: use structure for invalidate_range_start/end calls v2	2018-12-28 12:11:50 -08:00
mremap.c	mm: speed up mremap by 20x on large regions	2019-01-04 13:13:48 -08:00
msync.c
nommu.c	mm/gup: cache dev_pagemap while pinning pages	2018-10-26 16:38:15 -07:00
oom_kill.c	mm/mmu_notifier: use structure for invalidate_range_start/end calls v2	2018-12-28 12:11:50 -08:00
page-writeback.c	mm/page-writeback.c: don't break integrity writeback on ->writepage() error	2018-12-28 12:11:49 -08:00
page_alloc.c	mm/page_alloc.c: allow error injection	2018-12-28 12:11:51 -08:00
page_counter.c
page_ext.c	mm: remove include/linux/bootmem.h	2018-10-31 08:54:16 -07:00
page_idle.c	mm: remove include/linux/bootmem.h	2018-10-31 08:54:16 -07:00
page_io.c	mm/page_io.c: fix polled swap page in	2019-01-04 13:13:48 -08:00
page_isolation.c	mm: only report isolation failures when offlining memory	2018-12-28 12:11:46 -08:00
page_owner.c	mm/page_owner: clamp read count to PAGE_SIZE	2018-12-28 12:11:46 -08:00
page_poison.c	virtio, vhost: fixes, tweaks	2018-11-01 14:42:49 -07:00
page_vma_mapped.c	mm/rmap: map_pte() was not handling private ZONE_DEVICE page properly	2018-10-31 08:54:11 -07:00
pagewalk.c
percpu-internal.h
percpu-km.c	percpu: convert spin_lock_irq to spin_lock_irqsave.	2018-12-18 09:04:08 -08:00
percpu-stats.c	treewide: Use array_size() in vmalloc()	2018-06-12 16:19:22 -07:00
percpu-vm.c
percpu.c	Merge branch 'for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu	2018-11-01 09:27:57 -07:00
pgtable-generic.c	x86/mm: Page size aware flush_tlb_mm_range()	2018-10-09 16:51:11 +02:00
process_vm_access.c
quicklist.c
readahead.c	mm/readahead.c: simplify get_next_ra_size()	2018-12-28 12:11:46 -08:00
rmap.c	hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization	2018-12-28 12:11:51 -08:00
rodata_test.c
shmem.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
slab.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
slab.h	kasan, mm: change hooks signatures	2018-12-28 12:11:43 -08:00
slab_common.c	A fairly normal cycle for documentation stuff. We have a new	2018-12-29 11:21:49 -08:00
slob.c
slub.c	mm/slub.c: record final state of slub action in deactivate_slab()	2018-12-28 12:11:46 -08:00
sparse-vmemmap.c	mm: remove include/linux/bootmem.h	2018-10-31 08:54:16 -07:00
sparse.c	mm, sparse: pass nid instead of pgdat to sparse_add_one_section()	2018-12-28 12:11:49 -08:00
swap.c	fs: don't open code lru_to_page()	2019-01-04 13:13:48 -08:00
swap_cgroup.c
swap_slots.c	mm, swap, get_swap_pages: use entry_size instead of cluster in parameter	2018-08-22 10:52:44 -07:00
swap_state.c	Merge branch 'xarray' of git://git.infradead.org/users/willy/linux-dax	2018-10-28 11:35:40 -07:00
swapfile.c	mm, swap: fix swapoff with KSM pages	2018-12-28 12:11:52 -08:00
truncate.c	mm: cleancache: fix corruption on missed inode invalidation	2018-11-30 14:56:14 -08:00
usercopy.c	usercopy: Allow boot cmdline disabling of hardening	2018-07-04 08:04:52 -07:00
userfaultfd.c	mm: treewide: remove unused address argument from pte_alloc functions	2019-01-04 13:13:47 -08:00
util.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
vmacache.c	mm: get rid of vmacache_flush_all() entirely	2018-09-13 15:18:04 -10:00
vmalloc.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
vmpressure.c
vmscan.c	mm: put_and_wait_on_page_locked() while page is migrated	2018-12-28 12:11:48 -08:00
vmstat.c	mm: convert zone->managed_pages to atomic variable	2018-12-28 12:11:47 -08:00
workingset.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
z3fold.c	z3fold: fix possible reclaim races	2018-11-18 10:15:09 -08:00
zbud.c
zpool.c
zsmalloc.c	mm/zsmalloc.c: fix fall-through annotation	2018-10-26 16:26:35 -07:00
zswap.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00