On Mon, Nov 07, 2022 at 08:11:35PM +0100, Petr Vorel wrote: > Hi all, > > following bug is trying to workaround an error on ppc64le, where > zram01.sh LTP test (there is also kernel selftest > tools/testing/selftests/zram/zram01.sh, but LTP test got further > updates) has often mem_used_total 0 although zram is already filled. Hi, Petr, Is it happening on only ppc64le? Is it a new regression? What kernel version did you use? Actually, mem_used_total indicates how many *physical memory* were currently used to keep original data size. However, if the test data is repeated pattern of unsigned long (https://github.com/torvalds/linux/blob/master/drivers/block/zram/zram_drv.c#L210) zram doesn't allocate the physical memory but just mark the unsigned long's value in meta area for decompression later. Not sure you hit the this case. > > Patch tries to repeatedly read /sys/block/zram*/mm_stat for 1 sec, > waiting for mem_used_total > 0. The question if this is expected and > should be workarounded or a bug which should be fixed. > > REPRODUCE THE ISSUE > Quickest way to install only zram tests and their dependencies: > make autotools && ./configure && for i in testcases/lib/ testcases/kernel/device-drivers/zram/; do cd $i && make -j$(getconf _NPROCESSORS_ONLN) && make install && cd -; done > > Run the test (only on vfat) > PATH="/opt/ltp/testcases/bin:$PATH" LTP_SINGLE_FS_TYPE=vfat zram01.sh > > Petr Vorel (1): > zram01.sh: Workaround division by 0 on vfat on ppc64le > > .../kernel/device-drivers/zram/zram01.sh | 27 +++++++++++++++++-- > 1 file changed, 25 insertions(+), 2 deletions(-) > > -- > 2.38.0 >
