Vlastimil Babka 8e57f8acbb mm, debug_pagealloc: don't rely on static keys too early ... Commit 96a2b03f28 ("mm, debug_pagelloc: use static keys to enable debugging") has introduced a static key to reduce overhead when debug_pagealloc is compiled in but not enabled. It relied on the assumption that jump_label_init() is called before parse_early_param() as in start_kernel(), so when the "debug_pagealloc=on" option is parsed, it is safe to enable the static key. However, it turns out multiple architectures call parse_early_param() earlier from their setup_arch(). x86 also calls jump_label_init() even earlier, so no issue was found while testing the commit, but same is not true for e.g. ppc64 and s390 where the kernel would not boot with debug_pagealloc=on as found by our QA. To fix this without tricky changes to init code of multiple architectures, this patch partially reverts the static key conversion from 96a2b03f28. Init-time and non-fastpath calls (such as in arch code) of debug_pagealloc_enabled() will again test a simple bool variable. Fastpath mm code is converted to a new debug_pagealloc_enabled_static() variant that relies on the static key, which is enabled in a well-defined point in mm_init() where it's guaranteed that jump_label_init() has been called, regardless of architecture. [sfr@canb.auug.org.au: export _debug_pagealloc_enabled_early] Link: http://lkml.kernel.org/r/20200106164944.063ac07b@canb.auug.org.au Link: http://lkml.kernel.org/r/20191219130612.23171-1-vbabka@suse.cz Fixes: 96a2b03f28 ("mm, debug_pagelloc: use static keys to enable debugging") Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Qian Cai <cai@lca.pw> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2020-01-13 18:19:02 -08:00
..
kasan
backing-dev.c
balloon_compaction.c
cleancache.c
cma_debug.c
cma.c
cma.h
compaction.c
debug_page_ref.c
debug.c
dmapool.c
early_ioremap.c
fadvise.c
failslab.c
filemap.c
frame_vector.c
frontswap.c
gup_benchmark.c	mm/gup: fix memory leak in __gup_benchmark_ioctl	2020-01-04 13:55:09 -08:00
gup.c
highmem.c
hmm.c
huge_memory.c	mm/huge_memory.c: thp: fix conflict of above-47bit hint address and PMD alignment	2020-01-13 18:19:01 -08:00
hugetlb_cgroup.c
hugetlb.c	mm/hugetlb: defer freeing of huge pages if in non-task context	2020-01-04 13:55:09 -08:00
hwpoison-inject.c
init-mm.c
internal.h
interval_tree.c
Kconfig
Kconfig.debug
khugepaged.c
kmemleak-test.c
kmemleak.c
ksm.c
list_lru.c
maccess.c
madvise.c
Makefile
mapping_dirty_helpers.c
memblock.c
memcontrol.c	mm: memcg/slab: fix percpu slab vmstats flushing	2020-01-13 18:19:02 -08:00
memfd.c
memory_hotplug.c
memory-failure.c
memory.c
mempolicy.c	mm, thp: tweak reclaim/compaction effort of local-only and all-node allocations	2020-01-13 18:19:01 -08:00
mempool.c
memremap.c
memtest.c
migrate.c	mm: move_pages: return valid node id in status if the page is already on the target node	2020-01-04 13:55:09 -08:00
mincore.c
mlock.c
mm_init.c
mmap.c	arm64: Revert support for execute-only user mappings	2020-01-06 10:10:07 -08:00
mmu_context.c
mmu_gather.c
mmu_notifier.c
mmzone.c
mprotect.c
mremap.c
msync.c
nommu.c
oom_kill.c	mm/oom: fix pgtables units mismatch in Killed process message	2020-01-04 13:55:09 -08:00
page_alloc.c	mm, debug_pagealloc: don't rely on static keys too early	2020-01-13 18:19:02 -08:00
page_counter.c
page_ext.c
page_idle.c
page_io.c
page_isolation.c
page_owner.c
page_poison.c
page_vma_mapped.c
page-writeback.c
pagewalk.c
percpu-internal.h
percpu-km.c
percpu-stats.c
percpu-vm.c
percpu.c
pgtable-generic.c
process_vm_access.c
readahead.c
rmap.c
rodata_test.c
shmem.c	mm/shmem.c: thp, shmem: fix conflict of above-47bit hint address and PMD alignment	2020-01-13 18:19:01 -08:00
shuffle.c
shuffle.h
slab_common.c
slab.c	mm, debug_pagealloc: don't rely on static keys too early	2020-01-13 18:19:02 -08:00
slab.h
slob.c
slub.c	mm, debug_pagealloc: don't rely on static keys too early	2020-01-13 18:19:02 -08:00
sparse-vmemmap.c
sparse.c	mm/memory_hotplug: don't free usage map when removing a re-added early section	2020-01-13 18:19:01 -08:00
swap_cgroup.c
swap_slots.c
swap_state.c
swap.c
swapfile.c
truncate.c
usercopy.c
userfaultfd.c
util.c
vmacache.c
vmalloc.c	mm, debug_pagealloc: don't rely on static keys too early	2020-01-13 18:19:02 -08:00
vmpressure.c
vmscan.c
vmstat.c
workingset.c
z3fold.c
zbud.c
zpool.c
zsmalloc.c	mm/zsmalloc.c: fix the migrated zspage statistics.	2020-01-04 13:55:09 -08:00
zswap.c