On Mon, Nov 21, 2022 at 06:12:02PM +0100, Vlastimil Babka wrote: > As explained in [1], we would like to remove SLOB if possible. > > - There are no known users that need its somewhat lower memory footprint > so much that they cannot handle SLUB (after some modifications by the > previous patches) instead. > > - It is an extra maintenance burden, and a number of features are > incompatible with it. > > - It blocks the API improvement of allowing kfree() on objects allocated > via kmem_cache_alloc(). > > As the first step, rename the CONFIG_SLOB option in the slab allocator > configuration choice to CONFIG_SLOB_DEPRECATED. Add CONFIG_SLOB > depending on CONFIG_SLOB_DEPRECATED as an internal option to avoid code > churn. This will cause existing .config files and defconfigs with > CONFIG_SLOB=y to silently switch to the default (and recommended > replacement) SLUB, while still allowing SLOB to be configured by anyone > that notices and needs it. But those should contact the slab maintainers > and linux-mm@xxxxxxxxx as explained in the updated help. With no valid > objections, the plan is to update the existing defconfigs to SLUB and > remove SLOB in a few cycles. > > To make SLUB more suitable replacement for SLOB, a CONFIG_SLUB_TINY > option was introduced to limit SLUB's memory overhead. > There is a number of defconfigs specifying CONFIG_SLOB=y. As part of > this patch, update them to select CONFIG_SLUB and CONFIG_SLUB_TINY. > > [1] https://lore.kernel.org/all/b35c3f82-f67b-2103-7d82-7a7ba7521439@xxxxxxx/ > > Cc: Russell King <linux@xxxxxxxxxxxxxxx> > Cc: Aaro Koskinen <aaro.koskinen@xxxxxx> > Cc: Janusz Krzysztofik <jmkrzyszt@xxxxxxxxx> > Cc: Tony Lindgren <tony@xxxxxxxxxxx> > Cc: Jonas Bonn <jonas@xxxxxxxxxxxx> > Cc: Stefan Kristiansson <stefan.kristiansson@xxxxxxxxxxxxx> > Cc: Stafford Horne <shorne@xxxxxxxxx> > Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx> > Cc: Rich Felker <dalias@xxxxxxxx> > Cc: Arnd Bergmann <arnd@xxxxxxxx> > Cc: Josh Triplett <josh@xxxxxxxxxxxxxxxx> > Cc: Conor Dooley <conor@xxxxxxxxxx> > Cc: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx> > Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx> > Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> > Cc: <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx> > Cc: <linux-omap@xxxxxxxxxxxxxxx> > Cc: <openrisc@xxxxxxxxxxxxxxxxxxxx> > Cc: <linux-riscv@xxxxxxxxxxxxxxxxxxx> > Cc: <linux-sh@xxxxxxxxxxxxxxx> > Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx> > --- > arch/arm/configs/clps711x_defconfig | 3 ++- > arch/arm/configs/collie_defconfig | 3 ++- > arch/arm/configs/multi_v4t_defconfig | 3 ++- > arch/arm/configs/omap1_defconfig | 3 ++- > arch/arm/configs/pxa_defconfig | 3 ++- > arch/arm/configs/tct_hammer_defconfig | 3 ++- > arch/arm/configs/xcep_defconfig | 3 ++- > arch/openrisc/configs/or1ksim_defconfig | 3 ++- > arch/openrisc/configs/simple_smp_defconfig | 3 ++- > arch/riscv/configs/nommu_k210_defconfig | 3 ++- > arch/riscv/configs/nommu_k210_sdcard_defconfig | 3 ++- > arch/riscv/configs/nommu_virt_defconfig | 3 ++- > arch/sh/configs/rsk7201_defconfig | 3 ++- > arch/sh/configs/rsk7203_defconfig | 3 ++- > arch/sh/configs/se7206_defconfig | 3 ++- > arch/sh/configs/shmin_defconfig | 3 ++- > arch/sh/configs/shx3_defconfig | 3 ++- > kernel/configs/tiny.config | 5 +++-- > mm/Kconfig | 17 +++++++++++++++-- > 19 files changed, 52 insertions(+), 21 deletions(-) > > diff --git a/arch/arm/configs/clps711x_defconfig b/arch/arm/configs/clps711x_defconfig > index 92481b2a88fa..adcee238822a 100644 > --- a/arch/arm/configs/clps711x_defconfig > +++ b/arch/arm/configs/clps711x_defconfig > @@ -14,7 +14,8 @@ CONFIG_ARCH_EDB7211=y > CONFIG_ARCH_P720T=y > CONFIG_AEABI=y > # CONFIG_COREDUMP is not set > -CONFIG_SLOB=y > +CONFIG_SLUB=y > +CONFIG_SLUB_TINY=y > CONFIG_NET=y > CONFIG_PACKET=y > CONFIG_UNIX=y > diff --git a/arch/arm/configs/collie_defconfig b/arch/arm/configs/collie_defconfig > index 2a2d2cb3ce2e..69341c33e0cc 100644 > --- a/arch/arm/configs/collie_defconfig > +++ b/arch/arm/configs/collie_defconfig > @@ -13,7 +13,8 @@ CONFIG_CMDLINE="noinitrd root=/dev/mtdblock2 rootfstype=jffs2 fbcon=rotate:1" > CONFIG_FPE_NWFPE=y > CONFIG_PM=y > # CONFIG_SWAP is not set > -CONFIG_SLOB=y > +CONFIG_SLUB=y > +CONFIG_SLUB_TINY=y > CONFIG_NET=y > CONFIG_PACKET=y > CONFIG_UNIX=y > diff --git a/arch/arm/configs/multi_v4t_defconfig b/arch/arm/configs/multi_v4t_defconfig > index e2fd822f741a..b60000a89aff 100644 > --- a/arch/arm/configs/multi_v4t_defconfig > +++ b/arch/arm/configs/multi_v4t_defconfig > @@ -25,7 +25,8 @@ CONFIG_ARM_CLPS711X_CPUIDLE=y > CONFIG_JUMP_LABEL=y > CONFIG_PARTITION_ADVANCED=y > # CONFIG_COREDUMP is not set > -CONFIG_SLOB=y > +CONFIG_SLUB=y > +CONFIG_SLUB_TINY=y > CONFIG_MTD=y > CONFIG_MTD_CMDLINE_PARTS=y > CONFIG_MTD_BLOCK=y > diff --git a/arch/arm/configs/omap1_defconfig b/arch/arm/configs/omap1_defconfig > index 70511fe4b3ec..246f1bba7df5 100644 > --- a/arch/arm/configs/omap1_defconfig > +++ b/arch/arm/configs/omap1_defconfig > @@ -42,7 +42,8 @@ CONFIG_MODULE_FORCE_UNLOAD=y > CONFIG_PARTITION_ADVANCED=y > CONFIG_BINFMT_MISC=y > # CONFIG_SWAP is not set > -CONFIG_SLOB=y > +CONFIG_SLUB=y > +CONFIG_SLUB_TINY=y > # CONFIG_VM_EVENT_COUNTERS is not set > CONFIG_NET=y > CONFIG_PACKET=y > diff --git a/arch/arm/configs/pxa_defconfig b/arch/arm/configs/pxa_defconfig > index d60cc9cc4c21..0a0f12df40b5 100644 > --- a/arch/arm/configs/pxa_defconfig > +++ b/arch/arm/configs/pxa_defconfig > @@ -49,7 +49,8 @@ CONFIG_PARTITION_ADVANCED=y > CONFIG_LDM_PARTITION=y > CONFIG_CMDLINE_PARTITION=y > CONFIG_BINFMT_MISC=y > -CONFIG_SLOB=y > +CONFIG_SLUB=y > +CONFIG_SLUB_TINY=y > # CONFIG_COMPACTION is not set > CONFIG_NET=y > CONFIG_PACKET=y > diff --git a/arch/arm/configs/tct_hammer_defconfig b/arch/arm/configs/tct_hammer_defconfig > index 3b29ae1fb750..6bd38b6f22c4 100644 > --- a/arch/arm/configs/tct_hammer_defconfig > +++ b/arch/arm/configs/tct_hammer_defconfig > @@ -19,7 +19,8 @@ CONFIG_FPE_NWFPE=y > CONFIG_MODULES=y > CONFIG_MODULE_UNLOAD=y > # CONFIG_SWAP is not set > -CONFIG_SLOB=y > +CONFIG_SLUB=y > +CONFIG_SLUB_TINY=y > CONFIG_NET=y > CONFIG_PACKET=y > CONFIG_UNIX=y > diff --git a/arch/arm/configs/xcep_defconfig b/arch/arm/configs/xcep_defconfig > index ea59e4b6bfc5..6bd9f71b71fc 100644 > --- a/arch/arm/configs/xcep_defconfig > +++ b/arch/arm/configs/xcep_defconfig > @@ -26,7 +26,8 @@ CONFIG_MODULE_UNLOAD=y > CONFIG_MODVERSIONS=y > CONFIG_MODULE_SRCVERSION_ALL=y > # CONFIG_BLOCK is not set > -CONFIG_SLOB=y > +CONFIG_SLUB=y > +CONFIG_SLUB_TINY=y > # CONFIG_COMPAT_BRK is not set > # CONFIG_VM_EVENT_COUNTERS is not set > CONFIG_NET=y > diff --git a/arch/openrisc/configs/or1ksim_defconfig b/arch/openrisc/configs/or1ksim_defconfig > index 6e1e004047c7..0116e465238f 100644 > --- a/arch/openrisc/configs/or1ksim_defconfig > +++ b/arch/openrisc/configs/or1ksim_defconfig > @@ -10,7 +10,8 @@ CONFIG_EXPERT=y > # CONFIG_AIO is not set > # CONFIG_VM_EVENT_COUNTERS is not set > # CONFIG_COMPAT_BRK is not set > -CONFIG_SLOB=y > +CONFIG_SLUB=y > +CONFIG_SLUB_TINY=y > CONFIG_MODULES=y > # CONFIG_BLOCK is not set > CONFIG_OPENRISC_BUILTIN_DTB="or1ksim" > diff --git a/arch/openrisc/configs/simple_smp_defconfig b/arch/openrisc/configs/simple_smp_defconfig > index ff49d868e040..b990cb6c9309 100644 > --- a/arch/openrisc/configs/simple_smp_defconfig > +++ b/arch/openrisc/configs/simple_smp_defconfig > @@ -16,7 +16,8 @@ CONFIG_EXPERT=y > # CONFIG_AIO is not set > # CONFIG_VM_EVENT_COUNTERS is not set > # CONFIG_COMPAT_BRK is not set > -CONFIG_SLOB=y > +CONFIG_SLUB=y > +CONFIG_SLUB_TINY=y > CONFIG_MODULES=y > # CONFIG_BLOCK is not set > CONFIG_OPENRISC_BUILTIN_DTB="simple_smp" > diff --git a/arch/riscv/configs/nommu_k210_defconfig b/arch/riscv/configs/nommu_k210_defconfig > index 96fe8def644c..79b3ccd58ff0 100644 > --- a/arch/riscv/configs/nommu_k210_defconfig > +++ b/arch/riscv/configs/nommu_k210_defconfig > @@ -25,7 +25,8 @@ CONFIG_CC_OPTIMIZE_FOR_SIZE=y > CONFIG_EMBEDDED=y > # CONFIG_VM_EVENT_COUNTERS is not set > # CONFIG_COMPAT_BRK is not set > -CONFIG_SLOB=y > +CONFIG_SLUB=y > +CONFIG_SLUB_TINY=y > # CONFIG_MMU is not set > CONFIG_SOC_CANAAN=y > CONFIG_NONPORTABLE=y > diff --git a/arch/riscv/configs/nommu_k210_sdcard_defconfig b/arch/riscv/configs/nommu_k210_sdcard_defconfig > index 379740654373..6b80bb13b8ed 100644 > --- a/arch/riscv/configs/nommu_k210_sdcard_defconfig > +++ b/arch/riscv/configs/nommu_k210_sdcard_defconfig > @@ -17,7 +17,8 @@ CONFIG_CC_OPTIMIZE_FOR_SIZE=y > CONFIG_EMBEDDED=y > # CONFIG_VM_EVENT_COUNTERS is not set > # CONFIG_COMPAT_BRK is not set > -CONFIG_SLOB=y > +CONFIG_SLUB=y > +CONFIG_SLUB_TINY=y > # CONFIG_MMU is not set > CONFIG_SOC_CANAAN=y > CONFIG_NONPORTABLE=y > diff --git a/arch/riscv/configs/nommu_virt_defconfig b/arch/riscv/configs/nommu_virt_defconfig > index 1a56eda5ce46..4cf0f297091e 100644 > --- a/arch/riscv/configs/nommu_virt_defconfig > +++ b/arch/riscv/configs/nommu_virt_defconfig > @@ -22,7 +22,8 @@ CONFIG_EXPERT=y > # CONFIG_KALLSYMS is not set > # CONFIG_VM_EVENT_COUNTERS is not set > # CONFIG_COMPAT_BRK is not set > -CONFIG_SLOB=y > +CONFIG_SLUB=y > +CONFIG_SLUB_TINY=y > # CONFIG_MMU is not set > CONFIG_SOC_VIRT=y > CONFIG_NONPORTABLE=y > diff --git a/arch/sh/configs/rsk7201_defconfig b/arch/sh/configs/rsk7201_defconfig > index 619c18699459..376e95fa77bc 100644 > --- a/arch/sh/configs/rsk7201_defconfig > +++ b/arch/sh/configs/rsk7201_defconfig > @@ -10,7 +10,8 @@ CONFIG_USER_NS=y > CONFIG_PID_NS=y > CONFIG_BLK_DEV_INITRD=y > # CONFIG_AIO is not set > -CONFIG_SLOB=y > +CONFIG_SLUB=y > +CONFIG_SLUB_TINY=y > CONFIG_PROFILING=y > CONFIG_MODULES=y > # CONFIG_BLK_DEV_BSG is not set > diff --git a/arch/sh/configs/rsk7203_defconfig b/arch/sh/configs/rsk7203_defconfig > index d00fafc021e1..1d5fd67a3949 100644 > --- a/arch/sh/configs/rsk7203_defconfig > +++ b/arch/sh/configs/rsk7203_defconfig > @@ -11,7 +11,8 @@ CONFIG_USER_NS=y > CONFIG_PID_NS=y > CONFIG_BLK_DEV_INITRD=y > CONFIG_KALLSYMS_ALL=y > -CONFIG_SLOB=y > +CONFIG_SLUB=y > +CONFIG_SLUB_TINY=y > CONFIG_PROFILING=y > CONFIG_MODULES=y > # CONFIG_BLK_DEV_BSG is not set > diff --git a/arch/sh/configs/se7206_defconfig b/arch/sh/configs/se7206_defconfig > index 122216123e63..78e0e7be57ee 100644 > --- a/arch/sh/configs/se7206_defconfig > +++ b/arch/sh/configs/se7206_defconfig > @@ -21,7 +21,8 @@ CONFIG_BLK_DEV_INITRD=y > CONFIG_KALLSYMS_ALL=y > # CONFIG_ELF_CORE is not set > # CONFIG_COMPAT_BRK is not set > -CONFIG_SLOB=y > +CONFIG_SLUB=y > +CONFIG_SLUB_TINY=y > CONFIG_PROFILING=y > CONFIG_MODULES=y > CONFIG_MODULE_UNLOAD=y > diff --git a/arch/sh/configs/shmin_defconfig b/arch/sh/configs/shmin_defconfig > index c0b6f40d01cc..e078b193a78a 100644 > --- a/arch/sh/configs/shmin_defconfig > +++ b/arch/sh/configs/shmin_defconfig > @@ -9,7 +9,8 @@ CONFIG_LOG_BUF_SHIFT=14 > # CONFIG_FUTEX is not set > # CONFIG_EPOLL is not set > # CONFIG_SHMEM is not set > -CONFIG_SLOB=y > +CONFIG_SLUB=y > +CONFIG_SLUB_TINY=y > # CONFIG_BLK_DEV_BSG is not set > CONFIG_CPU_SUBTYPE_SH7706=y > CONFIG_MEMORY_START=0x0c000000 > diff --git a/arch/sh/configs/shx3_defconfig b/arch/sh/configs/shx3_defconfig > index 32ec6eb1eabc..aa353dff7f19 100644 > --- a/arch/sh/configs/shx3_defconfig > +++ b/arch/sh/configs/shx3_defconfig > @@ -20,7 +20,8 @@ CONFIG_USER_NS=y > CONFIG_PID_NS=y > # CONFIG_CC_OPTIMIZE_FOR_SIZE is not set > CONFIG_KALLSYMS_ALL=y > -CONFIG_SLOB=y > +CONFIG_SLUB=y > +CONFIG_SLUB_TINY=y > CONFIG_PROFILING=y > CONFIG_KPROBES=y > CONFIG_MODULES=y > diff --git a/kernel/configs/tiny.config b/kernel/configs/tiny.config > index 8a44b93da0f3..c2f9c912df1c 100644 > --- a/kernel/configs/tiny.config > +++ b/kernel/configs/tiny.config > @@ -7,5 +7,6 @@ CONFIG_KERNEL_XZ=y > # CONFIG_KERNEL_LZO is not set > # CONFIG_KERNEL_LZ4 is not set > # CONFIG_SLAB is not set > -# CONFIG_SLUB is not set > -CONFIG_SLOB=y > +# CONFIG_SLOB_DEPRECATED is not set > +CONFIG_SLUB=y > +CONFIG_SLUB_TINY=y > diff --git a/mm/Kconfig b/mm/Kconfig > index 5941cb34e30d..dcc49c69552f 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -219,17 +219,30 @@ config SLUB > and has enhanced diagnostics. SLUB is the default choice for > a slab allocator. > > -config SLOB > +config SLOB_DEPRECATED > depends on EXPERT > - bool "SLOB (Simple Allocator)" > + bool "SLOB (Simple Allocator - DEPRECATED)" > depends on !PREEMPT_RT > help > + Deprecated and scheduled for removal in a few cycles. SLUB > + recommended as replacement. CONFIG_SLUB_TINY can be considered > + on systems with 16MB or less RAM. > + > + If you need SLOB to stay, please contact linux-mm@xxxxxxxxx and > + people listed in the SLAB ALLOCATOR section of MAINTAINERS file, > + with your use case. > + > SLOB replaces the stock allocator with a drastically simpler > allocator. SLOB is generally more space efficient but > does not perform as well on large systems. > > endchoice > > +config SLOB > + bool > + default y > + depends on SLOB_DEPRECATED > + > config SLUB_TINY > bool "Configure SLUB for minimal memory footprint" > depends on SLUB && EXPERT > -- > 2.38.1 FTR, Acked-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx> -- Thanks, Hyeonggon
