Hi Anshuman, On 7/22/21 5:11 PM, Anshuman Khandual wrote:
On 7/22/21 12:11 PM, Gavin Shan wrote:On 7/22/21 3:45 PM, Anshuman Khandual wrote:On 7/19/21 6:36 PM, Gavin Shan wrote:This uses struct pgtable_debug_args in PMD modifying tests. The allocated huge page is used when set_pmd_at() is used. The corresponding tests are skipped if the huge page doesn't exist. Besides, the unused variable @pmd_aligned in debug_vm_pgtable() is dropped.Please dont drop @pmd_aligned just yet.We need do so. Otherwise, there is build warning to complain something like 'unused variable' after this patch is applied.Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx> --- mm/debug_vm_pgtable.c | 102 ++++++++++++++++++++---------------------- 1 file changed, 48 insertions(+), 54 deletions(-) diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c index eb6dda88e0d9..cec3cbf99a6b 100644 --- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -213,54 +213,54 @@ static void __init pmd_basic_tests(struct pgtable_debug_args *args, int idx) WARN_ON(!pmd_bad(pmd_mkhuge(pmd))); } -static void __init pmd_advanced_tests(struct mm_struct *mm, - struct vm_area_struct *vma, pmd_t *pmdp, - unsigned long pfn, unsigned long vaddr, - pgprot_t prot, pgtable_t pgtable) +static void __init pmd_advanced_tests(struct pgtable_debug_args *args) { pmd_t pmd; + unsigned long vaddr = (args->vaddr & HPAGE_PMD_MASK); if (!has_transparent_hugepage()) return; pr_debug("Validating PMD advanced\n"); - /* Align the address wrt HPAGE_PMD_SIZE */ - vaddr &= HPAGE_PMD_MASK;Please just leave these unchanged. If has_transparent_hugepage() evaluates negative, it skips the masking operation. As mentioned earlier please avoid changing the test in any manner during these transition patches.Ok.+ if (args->pmd_pfn == ULONG_MAX) { + pr_debug("%s: Skipped\n", __func__); + return; + }Just return. Please dont call out "Skipped".Ok.- pgtable_trans_huge_deposit(mm, pmdp, pgtable); + pgtable_trans_huge_deposit(args->mm, args->pmdp, args->start_ptep); - pmd = pfn_pmd(pfn, prot); - set_pmd_at(mm, vaddr, pmdp, pmd); - pmdp_set_wrprotect(mm, vaddr, pmdp); - pmd = READ_ONCE(*pmdp); + pmd = pfn_pmd(args->pmd_pfn, args->page_prot); + set_pmd_at(args->mm, vaddr, args->pmdp, pmd); + pmdp_set_wrprotect(args->mm, vaddr, args->pmdp); + pmd = READ_ONCE(*(args->pmdp)); WARN_ON(pmd_write(pmd)); - pmdp_huge_get_and_clear(mm, vaddr, pmdp); - pmd = READ_ONCE(*pmdp); + pmdp_huge_get_and_clear(args->mm, vaddr, args->pmdp); + pmd = READ_ONCE(*(args->pmdp)); WARN_ON(!pmd_none(pmd)); - pmd = pfn_pmd(pfn, prot); + pmd = pfn_pmd(args->pmd_pfn, args->page_prot); pmd = pmd_wrprotect(pmd); pmd = pmd_mkclean(pmd); - set_pmd_at(mm, vaddr, pmdp, pmd); + set_pmd_at(args->mm, vaddr, args->pmdp, pmd); pmd = pmd_mkwrite(pmd); pmd = pmd_mkdirty(pmd); - pmdp_set_access_flags(vma, vaddr, pmdp, pmd, 1); - pmd = READ_ONCE(*pmdp); + pmdp_set_access_flags(args->vma, vaddr, args->pmdp, pmd, 1); + pmd = READ_ONCE(*(args->pmdp)); WARN_ON(!(pmd_write(pmd) && pmd_dirty(pmd))); - pmdp_huge_get_and_clear_full(vma, vaddr, pmdp, 1); - pmd = READ_ONCE(*pmdp); + pmdp_huge_get_and_clear_full(args->vma, vaddr, args->pmdp, 1); + pmd = READ_ONCE(*(args->pmdp)); WARN_ON(!pmd_none(pmd)); - pmd = pmd_mkhuge(pfn_pmd(pfn, prot)); + pmd = pmd_mkhuge(pfn_pmd(args->pmd_pfn, args->page_prot)); pmd = pmd_mkyoung(pmd); - set_pmd_at(mm, vaddr, pmdp, pmd); - pmdp_test_and_clear_young(vma, vaddr, pmdp); - pmd = READ_ONCE(*pmdp); + set_pmd_at(args->mm, vaddr, args->pmdp, pmd); + pmdp_test_and_clear_young(args->vma, vaddr, args->pmdp); + pmd = READ_ONCE(*(args->pmdp)); WARN_ON(pmd_young(pmd)); /* Clear the pte entries */ - pmdp_huge_get_and_clear(mm, vaddr, pmdp); - pgtable = pgtable_trans_huge_withdraw(mm, pmdp); + pmdp_huge_get_and_clear(args->mm, vaddr, args->pmdp); + pgtable_trans_huge_withdraw(args->mm, args->pmdp); } static void __init pmd_leaf_tests(struct pgtable_debug_args *args) @@ -417,12 +417,7 @@ static void __init pud_leaf_tests(struct pgtable_debug_args *args) { } #else /* !CONFIG_TRANSPARENT_HUGEPAGE */ static void __init pmd_basic_tests(struct pgtable_debug_args *args, int idx) { } static void __init pud_basic_tests(struct pgtable_debug_args *args, int idx) { } -static void __init pmd_advanced_tests(struct mm_struct *mm, - struct vm_area_struct *vma, pmd_t *pmdp, - unsigned long pfn, unsigned long vaddr, - pgprot_t prot, pgtable_t pgtable) -{ -} +static void __init pmd_advanced_tests(struct pgtable_debug_args *args) { } static void __init pud_advanced_tests(struct mm_struct *mm, struct vm_area_struct *vma, pud_t *pudp, unsigned long pfn, unsigned long vaddr, @@ -435,11 +430,11 @@ static void __init pmd_savedwrite_tests(struct pgtable_debug_args *args) { } #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP -static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot) +static void __init pmd_huge_tests(struct pgtable_debug_args *args) { pmd_t pmd; - if (!arch_vmap_pmd_supported(prot)) + if (!arch_vmap_pmd_supported(args->page_prot)) return; pr_debug("Validating PMD huge\n"); @@ -447,10 +442,11 @@ static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot) * X86 defined pmd_set_huge() verifies that the given * PMD is not a populated non-leaf entry. */ - WRITE_ONCE(*pmdp, __pmd(0)); - WARN_ON(!pmd_set_huge(pmdp, __pfn_to_phys(pfn), prot)); - WARN_ON(!pmd_clear_huge(pmdp)); - pmd = READ_ONCE(*pmdp); + WRITE_ONCE(*(args->pmdp), __pmd(0));Possible extra braces.Will drop it in v4, thanks!+ WARN_ON(!pmd_set_huge(args->pmdp, __pfn_to_phys(args->fixed_pmd_pfn), + args->page_prot));Dont break the line.Ok.+ WARN_ON(!pmd_clear_huge(args->pmdp)); + pmd = READ_ONCE(*(args->pmdp)); WARN_ON(!pmd_none(pmd)); } @@ -473,7 +469,7 @@ static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot) WARN_ON(!pud_none(pud)); } #else /* !CONFIG_HAVE_ARCH_HUGE_VMAP */ -static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot) { } +static void __init pmd_huge_tests(struct pgtable_debug_args *args) { } static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot) { } #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */ @@ -640,20 +636,19 @@ static void __init pte_clear_tests(struct pgtable_debug_args *args) WARN_ON(!pte_none(pte)); } -static void __init pmd_clear_tests(struct mm_struct *mm, pmd_t *pmdp) +static void __init pmd_clear_tests(struct pgtable_debug_args *args) { - pmd_t pmd = READ_ONCE(*pmdp); + pmd_t pmd = READ_ONCE(*(args->pmdp)); pr_debug("Validating PMD clear\n"); pmd = __pmd(pmd_val(pmd) | RANDOM_ORVALUE); - WRITE_ONCE(*pmdp, pmd); - pmd_clear(pmdp); - pmd = READ_ONCE(*pmdp); + WRITE_ONCE(*(args->pmdp), pmd); + pmd_clear(args->pmdp); + pmd = READ_ONCE(*(args->pmdp)); WARN_ON(!pmd_none(pmd)); } -static void __init pmd_populate_tests(struct mm_struct *mm, pmd_t *pmdp, - pgtable_t pgtable) +static void __init pmd_populate_tests(struct pgtable_debug_args *args) { pmd_t pmd; @@ -662,8 +657,8 @@ static void __init pmd_populate_tests(struct mm_struct *mm, pmd_t *pmdp, * This entry points to next level page table page. * Hence this must not qualify as pmd_bad(). */ - pmd_populate(mm, pmdp, pgtable); - pmd = READ_ONCE(*pmdp); + pmd_populate(args->mm, args->pmdp, args->start_ptep); + pmd = READ_ONCE(*(args->pmdp)); WARN_ON(pmd_bad(pmd)); } @@ -1159,7 +1154,7 @@ static int __init debug_vm_pgtable(void) pgtable_t saved_ptep; pgprot_t prot; phys_addr_t paddr; - unsigned long vaddr, pmd_aligned; + unsigned long vaddr; unsigned long pud_aligned; spinlock_t *ptl = NULL; int idx, ret; @@ -1194,7 +1189,6 @@ static int __init debug_vm_pgtable(void) */ paddr = __pa_symbol(&start_kernel); - pmd_aligned = (paddr & PMD_MASK) >> PAGE_SHIFT;Please dont drop these just yet and wait until [PATCH 11/12].Otherwise, it causes build warning: 'unused variable'.Why ? Just the evaluation of 'pmd_aligned' from 'paddr' should be enough to avoid such warning. 'pmd_aligned' need not be used afterwards.
It's not enough to avoid the warning. I apply the patches till
this one (PATCH[v3 08/12]) and have additional code to keep
@pmd_aligned, then I run into build warning as below:
diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index cec3cbf99a6b..961c9bb6fc7c 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -1154,7 +1154,7 @@ static int __init debug_vm_pgtable(void)
pgtable_t saved_ptep;
pgprot_t prot;
phys_addr_t paddr;
- unsigned long vaddr;
+ unsigned long vaddr, pmd_aligned;
unsigned long pud_aligned;
spinlock_t *ptl = NULL;
int idx, ret;
@@ -1189,6 +1189,7 @@ static int __init debug_vm_pgtable(void)
*/
paddr = __pa_symbol(&start_kernel);
+ pmd_aligned = (paddr & PMD_MASK) >> PAGE_SHIFT;
pud_aligned = (paddr & PUD_MASK) >> PAGE_SHIFT;
pgdp = pgd_offset(mm, vaddr);
[gwshan@gshan l]$ make W=1 mm/debug_vm_pgtable.o
:
mm/debug_vm_pgtable.c: In function ‘debug_vm_pgtable’:
mm/debug_vm_pgtable.c:1157:23: warning: variable ‘pmd_aligned’ set but not used [-Wunused-but-set-variable]
1157 | unsigned long vaddr, pmd_aligned;
| ^~~~~~~~~~~
By the way, 0-day is trying to build kernel with "W=1". It means the
build warnings will be reported by 0-day if the unused variables aren't
dropped from individual patches. It makes the review a bit harder. However,
we still need to keep each individual patch complete to make 'git bisect'
friendly.
Thanks,
Gavin
