| Message ID | 20220521143456.2759-1-jszhang@kernel.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | use static key to optimize pgtable_l4_enabled | expand |
On Sat, May 21, 2022 at 8:13 PM Jisheng Zhang <jszhang@kernel.org> wrote: > > The pgtable_l4|[l5]_enabled check sits at hot code path, performance > is impacted a lot. Since pgtable_l4|[l5]_enabled isn't changed after > boot, so static key can be used to solve the performance issue[1]. > > An unified way static key was introduced in [2], but it only targets > riscv isa extension. We dunno whether SV48 and SV57 will be considered > as isa extension, so the unified solution isn't used for > pgtable_l4[l5]_enabled now. > > patch1 fixes a NULL pointer deference if static key is used a bit earlier. > patch2 uses the static key to optimize pgtable_l4|[l5]_enabled. > > [1] http://lists.infradead.org/pipermail/linux-riscv/2021-December/011164.html > [2] https://lore.kernel.org/linux-riscv/20220517184453.3558-1-jszhang@kernel.org/T/#t > > Since v3: > - fix W=1 call to undeclared function 'static_branch_likely' error > > Since v2: > - move the W=1 warning fix to a separate patch > - move the unified way to use static key to a new patch series. > > Since v1: > - Add a W=1 warning fix > - Fix W=1 error > - Based on v5.18-rcN, since SV57 support is added, so convert > pgtable_l5_enabled as well. > > > > Jisheng Zhang (2): > riscv: move sbi_init() earlier before jump_label_init() > riscv: turn pgtable_l4|[l5]_enabled to static key for RV64 I have tested both these patches on QEMU RV64 and RV32. Tested-by: Anup Patel <anup@brainfault.org> Thanks, Anup > > arch/riscv/include/asm/pgalloc.h | 16 ++++---- > arch/riscv/include/asm/pgtable-32.h | 3 ++ > arch/riscv/include/asm/pgtable-64.h | 60 ++++++++++++++++++--------- > arch/riscv/include/asm/pgtable.h | 5 +-- > arch/riscv/kernel/cpu.c | 4 +- > arch/riscv/kernel/setup.c | 2 +- > arch/riscv/mm/init.c | 64 ++++++++++++++++++----------- > arch/riscv/mm/kasan_init.c | 16 ++++---- > 8 files changed, 104 insertions(+), 66 deletions(-) > > -- > 2.34.1 >
On Sat, 25 Jun 2022 21:33:07 PDT (-0700), anup@brainfault.org wrote: > On Sat, May 21, 2022 at 8:13 PM Jisheng Zhang <jszhang@kernel.org> wrote: >> >> The pgtable_l4|[l5]_enabled check sits at hot code path, performance >> is impacted a lot. Since pgtable_l4|[l5]_enabled isn't changed after >> boot, so static key can be used to solve the performance issue[1]. >> >> An unified way static key was introduced in [2], but it only targets >> riscv isa extension. We dunno whether SV48 and SV57 will be considered >> as isa extension, so the unified solution isn't used for >> pgtable_l4[l5]_enabled now. >> >> patch1 fixes a NULL pointer deference if static key is used a bit earlier. >> patch2 uses the static key to optimize pgtable_l4|[l5]_enabled. >> >> [1] http://lists.infradead.org/pipermail/linux-riscv/2021-December/011164.html >> [2] https://lore.kernel.org/linux-riscv/20220517184453.3558-1-jszhang@kernel.org/T/#t >> >> Since v3: >> - fix W=1 call to undeclared function 'static_branch_likely' error >> >> Since v2: >> - move the W=1 warning fix to a separate patch >> - move the unified way to use static key to a new patch series. >> >> Since v1: >> - Add a W=1 warning fix >> - Fix W=1 error >> - Based on v5.18-rcN, since SV57 support is added, so convert >> pgtable_l5_enabled as well. >> >> >> >> Jisheng Zhang (2): >> riscv: move sbi_init() earlier before jump_label_init() >> riscv: turn pgtable_l4|[l5]_enabled to static key for RV64 > > I have tested both these patches on QEMU RV64 and RV32. > > Tested-by: Anup Patel <anup@brainfault.org> > > Thanks, > Anup Thanks for testing these. Unfortunatly they're failing for me under my kasan+sparsemem-vmemmap config, which looks like a defconfig with CONFIG_KASAN=y # CONFIG_FLATMEM_MANUAL is not set CONFIG_SPARSEMEM_MANUAL=y CONFIG_SPARSEMEM=y # CONFIG_SPARSEMEM_VMEMMAP is not set Nothing's really jumping out and I'm not sure that's a super compelling configuration, but IIRC it's found a handful of issues before so I'm not sure it's sane to just toss it. I've put this all on the riscv-pgtable_static_key branch of kernel.org/palmer/linux . If nobody has the time to look then I'll try and give it another shot, but I'm pretty buried right now so happy to have the help. > >> >> arch/riscv/include/asm/pgalloc.h | 16 ++++---- >> arch/riscv/include/asm/pgtable-32.h | 3 ++ >> arch/riscv/include/asm/pgtable-64.h | 60 ++++++++++++++++++--------- >> arch/riscv/include/asm/pgtable.h | 5 +-- >> arch/riscv/kernel/cpu.c | 4 +- >> arch/riscv/kernel/setup.c | 2 +- >> arch/riscv/mm/init.c | 64 ++++++++++++++++++----------- >> arch/riscv/mm/kasan_init.c | 16 ++++---- >> 8 files changed, 104 insertions(+), 66 deletions(-) >> >> -- >> 2.34.1 >>
On Fri, Jul 01, 2022 at 08:48:25PM -0700, Palmer Dabbelt wrote: > On Sat, 25 Jun 2022 21:33:07 PDT (-0700), anup@brainfault.org wrote: > > On Sat, May 21, 2022 at 8:13 PM Jisheng Zhang <jszhang@kernel.org> wrote: > > > > > > The pgtable_l4|[l5]_enabled check sits at hot code path, performance > > > is impacted a lot. Since pgtable_l4|[l5]_enabled isn't changed after > > > boot, so static key can be used to solve the performance issue[1]. > > > > > > An unified way static key was introduced in [2], but it only targets > > > riscv isa extension. We dunno whether SV48 and SV57 will be considered > > > as isa extension, so the unified solution isn't used for > > > pgtable_l4[l5]_enabled now. > > > > > > patch1 fixes a NULL pointer deference if static key is used a bit earlier. > > > patch2 uses the static key to optimize pgtable_l4|[l5]_enabled. > > > > > > [1] http://lists.infradead.org/pipermail/linux-riscv/2021-December/011164.html > > > [2] https://lore.kernel.org/linux-riscv/20220517184453.3558-1-jszhang@kernel.org/T/#t > > > > > > Since v3: > > > - fix W=1 call to undeclared function 'static_branch_likely' error > > > > > > Since v2: > > > - move the W=1 warning fix to a separate patch > > > - move the unified way to use static key to a new patch series. > > > > > > Since v1: > > > - Add a W=1 warning fix > > > - Fix W=1 error > > > - Based on v5.18-rcN, since SV57 support is added, so convert > > > pgtable_l5_enabled as well. > > > > > > > > > > > > Jisheng Zhang (2): > > > riscv: move sbi_init() earlier before jump_label_init() > > > riscv: turn pgtable_l4|[l5]_enabled to static key for RV64 > > > > I have tested both these patches on QEMU RV64 and RV32. > > > > Tested-by: Anup Patel <anup@brainfault.org> > > > > Thanks, > > Anup > > Thanks for testing these. Unfortunatly they're failing for me under my > kasan+sparsemem-vmemmap config, which looks like a defconfig with > > CONFIG_KASAN=y > # CONFIG_FLATMEM_MANUAL is not set > CONFIG_SPARSEMEM_MANUAL=y > CONFIG_SPARSEMEM=y > # CONFIG_SPARSEMEM_VMEMMAP is not set Hi Palmer, Thank you for the hint, I find the reason: SPARSEMEM is the key, KASAN doesn't matter. To fix this issue, we need to move riscv_finalise_pgtable_lx() after sparse_init(). I will send out a newer version soon. > > Nothing's really jumping out and I'm not sure that's a super compelling > configuration, but IIRC it's found a handful of issues before so I'm not > sure it's sane to just toss it. > > I've put this all on the riscv-pgtable_static_key branch of > kernel.org/palmer/linux . If nobody has the time to look then I'll try and > give it another shot, but I'm pretty buried right now so happy to have the > help. Let me know if you want a seperate patch against riscv-pgtable_static_key branch. Thanks > > > > > > > > > arch/riscv/include/asm/pgalloc.h | 16 ++++---- > > > arch/riscv/include/asm/pgtable-32.h | 3 ++ > > > arch/riscv/include/asm/pgtable-64.h | 60 ++++++++++++++++++--------- > > > arch/riscv/include/asm/pgtable.h | 5 +-- > > > arch/riscv/kernel/cpu.c | 4 +- > > > arch/riscv/kernel/setup.c | 2 +- > > > arch/riscv/mm/init.c | 64 ++++++++++++++++++----------- > > > arch/riscv/mm/kasan_init.c | 16 ++++---- > > > 8 files changed, 104 insertions(+), 66 deletions(-) > > > > > > -- > > > 2.34.1 > > >