WSL2-Linux-Kernel/mm
Linus Torvalds 00a3d660cb Revert "fs: do not prefault sys_write() user buffer pages"
This reverts commit 998ef75ddb.

The commit itself does not appear to be buggy per se, but it is exposing
a bug in ext4 (and Ted thinks ext3 too, but we solved that by getting
rid of it).  It's too late in the release cycle to really worry about
this, even if Dave Hansen has a patch that may actually fix the
underlying ext4 problem.  We can (and should) revisit this for the next
release.

The problem is that moving the prefaulting later now exposes a special
case with partially successful writes that isn't handled correctly.  And
the prefaulting likely isn't normally even that much of a performance
issue - it looks like at least one reason Dave saw this in his
performance tests is that he also ran them on Skylake that now supports
the new SMAP code, which makes the normally very cheap user space
prefaulting noticeably more expensive.

Bisected-and-acked-by: Ted Ts'o <tytso@mit.edu>
Analyzed-and-acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-10-07 08:32:38 +01:00
..
kasan kasan: fix last shadow judgement in memory_is_poisoned_16() 2015-09-17 21:16:07 -07:00
Kconfig media updates for v4.3-rc1 2015-09-11 16:42:39 -07:00
Kconfig.debug
Makefile media updates for v4.3-rc1 2015-09-11 16:42:39 -07:00
backing-dev.c Merge branch 'for-4.3/blkcg' of git://git.kernel.dk/linux-block 2015-09-10 18:56:14 -07:00
balloon_compaction.c
bootmem.c
cleancache.c
cma.c
cma.h
cma_debug.c
compaction.c
debug-pagealloc.c
debug.c mm: introduce idle page tracking 2015-09-10 13:29:01 -07:00
dmapool.c dmapool: fix overflow condition in pool_find_page() 2015-10-01 21:42:35 -04:00
early_ioremap.c mm/early_ioremap: add explicit #include of asm/early_ioremap.h 2015-09-11 15:21:34 -07:00
fadvise.c
failslab.c
filemap.c Revert "fs: do not prefault sys_write() user buffer pages" 2015-10-07 08:32:38 +01:00
frame_vector.c
frontswap.c
gup.c
highmem.c
huge_memory.c mm: introduce idle page tracking 2015-09-10 13:29:01 -07:00
hugetlb.c mm: hugetlbfs: skip shared VMAs when unmapping private pages to satisfy a fault 2015-10-01 21:42:35 -04:00
hugetlb_cgroup.c
hwpoison-inject.c hwpoison: use page_cgroup_ino for filtering by memcg 2015-09-10 13:29:01 -07:00
init-mm.c
internal.h
interval_tree.c
kmemcheck.c
kmemleak-test.c
kmemleak.c kmemleak: use seq_hex_dump() to dump buffers 2015-09-10 13:29:01 -07:00
ksm.c
list_lru.c
maccess.c
madvise.c
memblock.c
memcontrol.c memcg: remove pcp_counter_lock 2015-10-01 21:42:35 -04:00
memory-failure.c hwpoison: use page_cgroup_ino for filtering by memcg 2015-09-10 13:29:01 -07:00
memory.c mm: use vma_is_anonymous() in create_huge_pmd() and wp_huge_pmd() 2015-09-10 13:29:01 -07:00
memory_hotplug.c
mempolicy.c
mempool.c
memtest.c
migrate.c memcg: fix dirty page migration 2015-10-01 21:42:35 -04:00
mincore.c
mlock.c
mm_init.c
mmap.c mm, dax: VMA with vm_ops->pfn_mkwrite wants to be write-notified 2015-09-22 15:09:53 -07:00
mmu_context.c
mmu_notifier.c mmu-notifier: add clear_young callback 2015-09-10 13:29:01 -07:00
mmzone.c
mprotect.c
mremap.c
msync.c
nobootmem.c
nommu.c mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff() 2015-09-10 13:29:01 -07:00
oom_kill.c
page-writeback.c Merge branch 'for-4.3/blkcg' of git://git.kernel.dk/linux-block 2015-09-10 18:56:14 -07:00
page_alloc.c
page_counter.c
page_ext.c mm: introduce idle page tracking 2015-09-10 13:29:01 -07:00
page_idle.c mm: introduce idle page tracking 2015-09-10 13:29:01 -07:00
page_io.c
page_isolation.c
page_owner.c
pagewalk.c
percpu-km.c
percpu-vm.c
percpu.c
pgtable-generic.c
process_vm_access.c
quicklist.c
readahead.c
rmap.c mm: introduce idle page tracking 2015-09-10 13:29:01 -07:00
shmem.c
slab.c mm/slab: fix unexpected index mapping result of kmalloc_size(INDEX_NODE+1) 2015-10-01 21:42:35 -04:00
slab.h
slab_common.c
slob.c
slub.c
sparse-vmemmap.c
sparse.c
swap.c mm: introduce idle page tracking 2015-09-10 13:29:01 -07:00
swap_cgroup.c
swap_state.c
swapfile.c
truncate.c
userfaultfd.c
util.c
vmacache.c
vmalloc.c
vmpressure.c
vmscan.c vmscan: fix sane_reclaim helper for legacy memcg 2015-09-22 15:09:53 -07:00
vmstat.c
workingset.c
zbud.c
zpool.c
zsmalloc.c
zswap.c zswap: change zpool/compressor at runtime 2015-09-10 13:29:01 -07:00