> On Apr 5, 2024, at 03:32, Vishal Moola <vishal.moola@xxxxxxxxx> wrote: > > On Thu, Apr 4, 2024 at 5:26 AM Oscar Salvador <osalvador@xxxxxxx> wrote: >> >> On Mon, Apr 01, 2024 at 01:26:49PM -0700, Vishal Moola (Oracle) wrote: >>> Now that hugetlb_fault() has a vm_fault available for fault tracking, use >>> it throughout. This cleans up the code by removing 2 variables, and >>> prepares hugetlb_fault() to take in a struct vm_fault argument. >>> >>> Signed-off-by: Vishal Moola (Oracle) <vishal.moola@xxxxxxxxx> >> >> Reviewed-by: Oscar Salvador <osalvador@xxxxxxx> >> >> A question below: >> >>> mm/hugetlb.c | 84 +++++++++++++++++++++++++--------------------------- >>> 1 file changed, 41 insertions(+), 43 deletions(-) >>> >>> diff --git a/mm/hugetlb.c b/mm/hugetlb.c >>> index 8267e221ca5d..360b82374a89 100644 >>> --- a/mm/hugetlb.c >>> +++ b/mm/hugetlb.c >> ... >>> /* >>> - * entry could be a migration/hwpoison entry at this point, so this >>> - * check prevents the kernel from going below assuming that we have >>> - * an active hugepage in pagecache. This goto expects the 2nd page >>> - * fault, and is_hugetlb_entry_(migration|hwpoisoned) check will >>> - * properly handle it. >>> + * vmf.orig_pte could be a migration/hwpoison vmf.orig_pte at this >> >> "vmf.orig_pte could be a migration/hwpoison entry at ..." >> >>> - entry = pte_mkyoung(entry); >>> - if (huge_ptep_set_access_flags(vma, haddr, ptep, entry, >>> + vmf.orig_pte = pte_mkyoung(vmf.orig_pte); >>> + if (huge_ptep_set_access_flags(vma, vmf.address, vmf.pte, vmf.orig_pte, >>> flags & FAULT_FLAG_WRITE)) >> >> Would it make sense to teach huge_ptep_set_access_flags/set_huge_pte_at() to use >> vm_fault struct as well? All info we are passing is stored there. >> Maybe it is not worth the trouble though, just asking. > > Yeah, it makes sense. There are actually many function calls in the > hugetlb_fault() and > __handle_mm_fault() pathways that could make use of vm_fault to clean > up the stack. > > It's not particularly complicated either, aside from reorganizing some > variables for every > implementation of each function. I'm not really sure if it's worth > dedicated effort > and churn though (at least I'm not focused on that for now). Not all the users of set_huge_pte_at() have a vmf structure. So I do not think it is a good idea to change it. And huge_ptep_set_access_flags() is a variant of ptep_set_access_flags(), it's better to keep consistent. Otherwise, I think both of them should be adapted if you want cleanup. My tendency is to remain unchanged. Muchun, Thanks.
