On Fri 09-06-17 08:48:58, Vlastimil Babka wrote: > On 06/08/2017 10:30 PM, Michal Hocko wrote: > > But I guess you are primary after syncing the preemptive mode for 64 and > > 32b systems, right? I agree that having a different model is more than > > unfortunate because 32b gets much less testing coverage and so a risk of > > introducing a new bug is just a matter of time. Maybe we should make > > pte_offset_map disable preemption and currently noop pte_unmap to > > preempt_enable. The overhead should be pretty marginal on x86_64 but not > > all arches have per-cpu preempt count. So I am not sure we really want > > to add this to just for the debugging purposes... > > I think adding that overhead for everyone would be unfortunate. It would > be acceptable, if it was done only for the config option that enables > the might_sleep() checks (CONFIG_DEBUG_ATOMIC_SLEEP?) That is certainly possible. But is it worth it? arch/alpha/include/asm/pgtable.h:#define pte_offset_map(dir,addr) pte_offset_kernel((dir),(addr)) arch/arc/include/asm/pgtable.h:#define pte_offset_map(dir, addr) pte_offset(dir, addr) arch/arm/include/asm/pgtable.h:#define pte_offset_map(pmd,addr) (__pte_map(pmd) + pte_index(addr)) arch/arm64/include/asm/pgtable.h:#define pte_offset_map(dir,addr) pte_offset_kernel((dir), (addr)) arch/arm64/include/asm/pgtable.h:#define pte_offset_map_nested(dir,addr) pte_offset_kernel((dir), (addr)) arch/cris/include/asm/pgtable.h:#define pte_offset_map(dir, address) \ arch/frv/include/asm/pgtable.h:#define pte_offset_map(dir, address) \ arch/frv/include/asm/pgtable.h:#define pte_offset_map(dir, address) \ arch/hexagon/include/asm/pgtable.h:#define pte_offset_map(dir, address) \ arch/hexagon/include/asm/pgtable.h:#define pte_offset_map_nested(pmd, addr) pte_offset_map(pmd, addr) arch/ia64/include/asm/pgtable.h:#define pte_offset_map(dir,addr) pte_offset_kernel(dir, addr) arch/m32r/include/asm/pgtable.h:#define pte_offset_map(dir, address) \ arch/m68k/include/asm/mcf_pgtable.h:#define pte_offset_map(pmdp, addr) ((pte_t *)__pmd_page(*pmdp) + \ arch/m68k/include/asm/motorola_pgtable.h:#define pte_offset_map(pmdp,address) ((pte_t *)__pmd_page(*pmdp) + (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))) arch/m68k/include/asm/sun3_pgtable.h:#define pte_offset_map(pmd, address) ((pte_t *)page_address(pmd_page(*pmd)) + pte_index(address)) arch/metag/include/asm/pgtable.h:#define pte_offset_map(dir, address) pte_offset_kernel(dir, address) arch/metag/include/asm/pgtable.h:#define pte_offset_map_nested(dir, address) pte_offset_kernel(dir, address) arch/microblaze/include/asm/pgtable.h:#define pte_offset_map(dir, addr) \ arch/mips/include/asm/pgtable-32.h:#define pte_offset_map(dir, address) \ arch/mips/include/asm/pgtable-64.h:#define pte_offset_map(dir, address) \ arch/mn10300/include/asm/pgtable.h:#define pte_offset_map(dir, address) \ arch/nios2/include/asm/pgtable.h:#define pte_offset_map(dir, addr) \ arch/openrisc/include/asm/pgtable.h:#define pte_offset_map(dir, address) \ arch/openrisc/include/asm/pgtable.h:#define pte_offset_map_nested(dir, address) \ arch/parisc/include/asm/pgtable.h:#define pte_offset_map(pmd, address) pte_offset_kernel(pmd, address) arch/powerpc/include/asm/book3s/32/pgtable.h:#define pte_offset_map(dir, addr) \ arch/powerpc/include/asm/book3s/64/pgtable.h:#define pte_offset_map(dir,addr) pte_offset_kernel((dir), (addr)) arch/powerpc/include/asm/nohash/32/pgtable.h:#define pte_offset_map(dir, addr) \ arch/powerpc/include/asm/nohash/64/pgtable.h:#define pte_offset_map(dir,addr) pte_offset_kernel((dir), (addr)) arch/s390/include/asm/pgtable.h:#define pte_offset_map(pmd, address) pte_offset_kernel(pmd, address) arch/score/include/asm/pgtable.h:#define pte_offset_map(dir, address) \ arch/sh/include/asm/pgtable_32.h:#define pte_offset_map(dir, address) pte_offset_kernel(dir, address) arch/sh/include/asm/pgtable_64.h:#define pte_offset_map(dir,addr) pte_offset_kernel(dir, addr) arch/sparc/include/asm/pgtable_32.h:#define pte_offset_map(d, a) pte_offset_kernel(d,a) arch/sparc/include/asm/pgtable_64.h:#define pte_offset_map pte_index arch/tile/include/asm/pgtable.h:#define pte_offset_map(dir, address) pte_offset_kernel(dir, address) arch/um/include/asm/pgtable.h:#define pte_offset_map(dir, address) \ arch/unicore32/include/asm/pgtable.h:#define pte_offset_map(dir, addr) (pmd_page_vaddr(*(dir)) \ arch/x86/include/asm/pgtable_32.h:#define pte_offset_map(dir, address) \ arch/x86/include/asm/pgtable_32.h:#define pte_offset_map(dir, address) \ arch/x86/include/asm/pgtable_64.h:#define pte_offset_map(dir, address) pte_offset_kernel((dir), (address)) arch/xtensa/include/asm/pgtable.h:#define pte_offset_map(dir,addr) pte_offset_kernel((dir),(addr)) include/linux/mm.h:#define pte_offset_map_lock(mm, pmd, address, ptlp) \ -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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