Re: [PATCH v3 1/2] mm: Abstract THP allocation
From: Kefeng Wang <hidden>
Date: 2024-09-11 10:52:47
Also in:
linux-mm, lkml
On 2024/9/11 14:55, Dev Jain wrote:
quoted hunk ↗ jump to hunk
In preparation for the second patch, abstract away the THP allocation logic present in the create_huge_pmd() path, which corresponds to the faulting case when no page is present. There should be no functional change as a result of applying this patch. Signed-off-by: Dev Jain <dev.jain@arm.com> --- mm/huge_memory.c | 110 +++++++++++++++++++++++++++++------------------ 1 file changed, 67 insertions(+), 43 deletions(-)diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 67c86a5d64a6..b96a1ff2bf40 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c@@ -943,47 +943,88 @@ unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, } EXPORT_SYMBOL_GPL(thp_get_unmapped_area); -static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, - struct page *page, gfp_t gfp) +static struct folio *pmd_thp_fault_alloc(gfp_t gfp, struct vm_area_struct *vma, + unsigned long haddr, unsigned long addr) { - struct vm_area_struct *vma = vmf->vma; - struct folio *folio = page_folio(page); - pgtable_t pgtable; - unsigned long haddr = vmf->address & HPAGE_PMD_MASK; - vm_fault_t ret = 0; + const int order = HPAGE_PMD_ORDER;
Maybe move vma_thp_gfp_mask() into this function too.
+ struct folio *folio = vma_alloc_folio(gfp, order, vma, haddr, true);
- VM_BUG_ON_FOLIO(!folio_test_large(folio), folio);
+ if (unlikely(!folio)) {
+ count_vm_event(THP_FAULT_FALLBACK);
+ count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK);
+ goto out;
+ }
+ VM_BUG_ON_FOLIO(!folio_test_large(folio), folio);
if (mem_cgroup_charge(folio, vma->vm_mm, gfp)) {
folio_put(folio);
count_vm_event(THP_FAULT_FALLBACK);
count_vm_event(THP_FAULT_FALLBACK_CHARGE);
- count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_FALLBACK);
- count_mthp_stat(HPAGE_PMD_ORDER, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE);
- return VM_FAULT_FALLBACK;
+ count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK);
+ count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE);
+ goto out;We need to return NULL here as folio not set to null,
}
folio_throttle_swaprate(folio, gfp);
- pgtable = pte_alloc_one(vma->vm_mm);
- if (unlikely(!pgtable)) {
- ret = VM_FAULT_OOM;
- goto release;
- }
-
- folio_zero_user(folio, vmf->address);
+ folio_zero_user(folio, addr);
/*
* The memory barrier inside __folio_mark_uptodate makes sure that
* folio_zero_user writes become visible before the set_pmd_at()
* write.
*/
__folio_mark_uptodate(folio);
+out:
+ return folio;
+}
+