On 06/25/2020 08:30 AM, Mike Kravetz wrote: > On 6/24/20 2:26 AM, Bibo Mao wrote: >> When set_pmd_at is called in function do_huge_pmd_anonymous_page, >> new tlb entry can be added by software on MIPS platform. >> >> Here add update_mmu_cache_pmd when pmd entry is set, and >> update_mmu_cache_pmd is defined as empty excepts arc/mips platform. >> This patch has no negative effect on other platforms except arc/mips >> system. > > I am confused by this comment. It appears that update_mmu_cache_pmd > is defined as non-empty on arc, mips, powerpc and sparc architectures. > Am I missing something? ohh, sparc is missing here, it not defined as empty. On powerpc it is defined as empty. > > If those architectures do provide update_mmu_cache_pmd, then the previous > patch and this one now call update_mmu_cache_pmd with the actual faulting > address instead of the huge page aligned address. This was intentional > for mips. However, are there any potential issues on the other architectures? It is not special for mips, only that fault address is useful on mips system. In function huge_pmd_set_accessed/do_huge_pmd_wp_page, update_mmu_cache_pmd is called with vmf->address, rather than start address of pmd page. regards bibo,mao > I am no expert in any of those architectures. arc looks like it could be > problematic as update_mmu_cache_pmd calls update_mmu_cache and then > operates on (address & PAGE_MASK). That could now be different.
