Revision 6460495709aeb651896bc8e5c134b2e4ca7d34a8 authored by James Wang on 08 June 2017, 06:52:51 UTC, committed by Jens Axboe on 08 June 2017, 14:04:18 UTC
While installing SLES-12 (based on v4.4), I found that the installer will stall for 60+ seconds during LVM disk scan. The root cause was determined to be the removal of a bound device check in loop_flush() by commit b5dd2f6047ca ("block: loop: improve performance via blk-mq"). Restoring this check, examining ->lo_state as set by loop_set_fd() eliminates the bad behavior. Test method: modprobe loop max_loop=64 dd if=/dev/zero of=disk bs=512 count=200K for((i=0;i<4;i++))do losetup -f disk; done mkfs.ext4 -F /dev/loop0 for((i=0;i<4;i++))do mkdir t$i; mount /dev/loop$i t$i;done for f in `ls /dev/loop[0-9]*|sort`; do \ echo $f; dd if=$f of=/dev/null bs=512 count=1; \ done Test output: stock patched /dev/loop0 18.1217e-05 8.3842e-05 /dev/loop1 6.1114e-05 0.000147979 /dev/loop10 0.414701 0.000116564 /dev/loop11 0.7474 6.7942e-05 /dev/loop12 0.747986 8.9082e-05 /dev/loop13 0.746532 7.4799e-05 /dev/loop14 0.480041 9.3926e-05 /dev/loop15 1.26453 7.2522e-05 Note that from loop10 onward, the device is not mounted, yet the stock kernel consumes several orders of magnitude more wall time than it does for a mounted device. (Thanks for Mike Galbraith <efault@gmx.de>, give a changelog review.) Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: James Wang <jnwang@suse.com> Fixes: b5dd2f6047ca ("block: loop: improve performance via blk-mq") Signed-off-by: Jens Axboe <axboe@fb.com>
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File | Mode | Size |
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kasan | ||
Kconfig | -rw-r--r-- | 23.9 KB |
Kconfig.debug | -rw-r--r-- | 3.8 KB |
Makefile | -rw-r--r-- | 3.5 KB |
backing-dev.c | -rw-r--r-- | 27.5 KB |
balloon_compaction.c | -rw-r--r-- | 4.7 KB |
bootmem.c | -rw-r--r-- | 20.8 KB |
cleancache.c | -rw-r--r-- | 9.9 KB |
cma.c | -rw-r--r-- | 13.5 KB |
cma.h | -rw-r--r-- | 534 bytes |
cma_debug.c | -rw-r--r-- | 4.5 KB |
compaction.c | -rw-r--r-- | 57.9 KB |
debug.c | -rw-r--r-- | 4.3 KB |
debug_page_ref.c | -rw-r--r-- | 1.3 KB |
dmapool.c | -rw-r--r-- | 13.7 KB |
early_ioremap.c | -rw-r--r-- | 6.2 KB |
fadvise.c | -rw-r--r-- | 4.3 KB |
failslab.c | -rw-r--r-- | 1.4 KB |
filemap.c | -rw-r--r-- | 79.8 KB |
frame_vector.c | -rw-r--r-- | 6.0 KB |
frontswap.c | -rw-r--r-- | 14.3 KB |
gup.c | -rw-r--r-- | 46.1 KB |
highmem.c | -rw-r--r-- | 11.7 KB |
huge_memory.c | -rw-r--r-- | 73.9 KB |
hugetlb.c | -rw-r--r-- | 127.8 KB |
hugetlb_cgroup.c | -rw-r--r-- | 10.9 KB |
hwpoison-inject.c | -rw-r--r-- | 3.2 KB |
init-mm.c | -rw-r--r-- | 680 bytes |
internal.h | -rw-r--r-- | 16.2 KB |
interval_tree.c | -rw-r--r-- | 3.1 KB |
khugepaged.c | -rw-r--r-- | 48.4 KB |
kmemcheck.c | -rw-r--r-- | 2.9 KB |
kmemleak-test.c | -rw-r--r-- | 3.2 KB |
kmemleak.c | -rw-r--r-- | 56.2 KB |
ksm.c | -rw-r--r-- | 65.5 KB |
list_lru.c | -rw-r--r-- | 12.6 KB |
maccess.c | -rw-r--r-- | 3.0 KB |
madvise.c | -rw-r--r-- | 21.5 KB |
memblock.c | -rw-r--r-- | 50.2 KB |
memcontrol.c | -rw-r--r-- | 154.6 KB |
memory-failure.c | -rw-r--r-- | 49.5 KB |
memory.c | -rw-r--r-- | 117.9 KB |
memory_hotplug.c | -rw-r--r-- | 55.5 KB |
mempolicy.c | -rw-r--r-- | 71.3 KB |
mempool.c | -rw-r--r-- | 13.9 KB |
memtest.c | -rw-r--r-- | 2.7 KB |
migrate.c | -rw-r--r-- | 52.2 KB |
mincore.c | -rw-r--r-- | 6.7 KB |
mlock.c | -rw-r--r-- | 22.6 KB |
mm_init.c | -rw-r--r-- | 4.8 KB |
mmap.c | -rw-r--r-- | 95.3 KB |
mmu_context.c | -rw-r--r-- | 1.3 KB |
mmu_notifier.c | -rw-r--r-- | 11.5 KB |
mmzone.c | -rw-r--r-- | 2.4 KB |
mprotect.c | -rw-r--r-- | 13.5 KB |
mremap.c | -rw-r--r-- | 16.2 KB |
msync.c | -rw-r--r-- | 2.6 KB |
nobootmem.c | -rw-r--r-- | 11.1 KB |
nommu.c | -rw-r--r-- | 48.6 KB |
oom_kill.c | -rw-r--r-- | 28.5 KB |
page-writeback.c | -rw-r--r-- | 84.5 KB |
page_alloc.c | -rw-r--r-- | 208.9 KB |
page_counter.c | -rw-r--r-- | 4.8 KB |
page_ext.c | -rw-r--r-- | 11.1 KB |
page_idle.c | -rw-r--r-- | 5.4 KB |
page_io.c | -rw-r--r-- | 9.4 KB |
page_isolation.c | -rw-r--r-- | 8.3 KB |
page_owner.c | -rw-r--r-- | 14.7 KB |
page_poison.c | -rw-r--r-- | 2.6 KB |
page_vma_mapped.c | -rw-r--r-- | 5.8 KB |
pagewalk.c | -rw-r--r-- | 8.4 KB |
percpu-km.c | -rw-r--r-- | 2.8 KB |
percpu-vm.c | -rw-r--r-- | 10.0 KB |
percpu.c | -rw-r--r-- | 66.8 KB |
pgtable-generic.c | -rw-r--r-- | 5.2 KB |
process_vm_access.c | -rw-r--r-- | 10.1 KB |
quicklist.c | -rw-r--r-- | 2.4 KB |
readahead.c | -rw-r--r-- | 16.1 KB |
rmap.c | -rw-r--r-- | 48.0 KB |
rodata_test.c | -rw-r--r-- | 1.4 KB |
shmem.c | -rw-r--r-- | 110.3 KB |
slab.c | -rw-r--r-- | 110.4 KB |
slab.h | -rw-r--r-- | 14.7 KB |
slab_common.c | -rw-r--r-- | 34.4 KB |
slob.c | -rw-r--r-- | 16.0 KB |
slub.c | -rw-r--r-- | 140.2 KB |
sparse-vmemmap.c | -rw-r--r-- | 8.1 KB |
sparse.c | -rw-r--r-- | 20.7 KB |
swap.c | -rw-r--r-- | 27.0 KB |
swap_cgroup.c | -rw-r--r-- | 4.7 KB |
swap_slots.c | -rw-r--r-- | 8.9 KB |
swap_state.c | -rw-r--r-- | 14.3 KB |
swapfile.c | -rw-r--r-- | 84.6 KB |
truncate.c | -rw-r--r-- | 25.3 KB |
usercopy.c | -rw-r--r-- | 7.5 KB |
userfaultfd.c | -rw-r--r-- | 14.3 KB |
util.c | -rw-r--r-- | 17.9 KB |
vmacache.c | -rw-r--r-- | 3.2 KB |
vmalloc.c | -rw-r--r-- | 69.7 KB |
vmpressure.c | -rw-r--r-- | 12.7 KB |
vmscan.c | -rw-r--r-- | 113.4 KB |
vmstat.c | -rw-r--r-- | 47.4 KB |
workingset.c | -rw-r--r-- | 18.4 KB |
z3fold.c | -rw-r--r-- | 23.8 KB |
zbud.c | -rw-r--r-- | 18.2 KB |
zpool.c | -rw-r--r-- | 10.0 KB |
zsmalloc.c | -rw-r--r-- | 59.3 KB |
zswap.c | -rw-r--r-- | 32.8 KB |
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