Greeting, Just FYI, we found the memory usage of slab after boot increased after applying your commit. This may be expected. We hope the number could be one of the measure data for you. commit: e381322b0190c1253d347de3f28b5c37756fb651 ("leds: Introduce userspace LED class driver") https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master in testcase: boot on test machine: qemu-system-x86_64 -enable-kvm -cpu host -smp 2 -m 1G with following parameters: sleep: 1 Details are as below: --------------------------------------------------------------------------------------------------> To reproduce: git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git cd lkp-tests bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email testcase/path_params/tbox_group/run: boot/1/vm-lkp-nex04-1G v4.9-rc1 e381322b0190c1253d347de3f2 ---------------- -------------------------- %stddev change %stddev \ | \ 8412 12% 9428 boot-slabinfo.num_pages 128104 11% 142675 boot-slabinfo.num_objs 5.64 ± 6% 28% 7.22 ± 3% boot-time.boot 7.17 ± 6% 23% 8.84 boot-time.idle 24118 ± 6% 33% 32128 ± 5% boot-meminfo.DirectMap4k 1609 20% 1931 ± 4% boot-meminfo.KernelStack 33678 12% 37672 boot-meminfo.Slab 673418 -49% 346205 boot-meminfo.MemFree boot-slabinfo.num_objs 146000 ++-----------------------------------------------------------------+ 144000 ++ O O O | |OO OO O | 142000 O+ O O O | 140000 ++ | | | 138000 ++ | 136000 ++ | 134000 *+ | | | 132000 ++ | 130000 ++ * * | |* ***** * **:: * ****** *** * ** *** * *** ***** * * * *** *| 128000 ++* * ** ** *** * * * *** * *** * ** ** ***** ***** **** ** * 126000 ++-----------------------------------------------------------------+ boot-slabinfo.num_pages 9600 ++-------------------------------------------------------------------+ |O O O O | 9400 OOOOOOOOOO | | | 9200 ++ | | | 9000 ++ | | | 8800 *+ | | | 8600 ++ | |* ** ** * * ** *| 8400 +*** **************************** ***************************** * ** | * * | 8200 ++-------------------------------------------------------------------+ boot-meminfo.MemFree 700000 ++-----------------------------------------------------------------+ ******************************************************************** 650000 ++ | | | 600000 ++ | 550000 ++ | | | 500000 ++ | | | 450000 ++ | 400000 ++ | | | 350000 OOOOOOOOOO | | O O | 300000 ++-----------------------------------------------------------------+ boot-meminfo.Slab 38000 +O-O------O---------------------------------------------------------+ 37500 +OOOOOOOOO | O | 37000 ++ | 36500 ++ | | | 36000 ++ | 35500 ++ | 35000 *+ | | | 34500 ++ | 34000 +* | |************** ********** ** ******* ****** ********************* ** 33500 ++ * * * * * * * * | 33000 ++------------------------------------------------------------------+ [*] bisect-good sample [O] bisect-bad sample Disclaimer: Results have been estimated based on internal Intel analysis and are provided for informational purposes only. Any difference in system hardware or software design or configuration may affect actual performance. Thanks, Ying Huang