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mm/huge: avoid big else branch in zap_huge_pmd()

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We don't need to have an extra level of indentation, we can simply exit
early in the first two branches.

No functional change intended.

Link: https://lkml.kernel.org/r/6b4d5efdbf5554b8fe788f677d0b50f355eec999.1774029655.git.ljs@kernel.org
Signed-off-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Lorenzo Stoakes (Oracle) 2026-03-20 18:07:19 +00:00 committed by Andrew Morton
parent c0ea52c18c
commit 6886f93790
1 changed files with 53 additions and 50 deletions
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103
mm/huge_memory.c
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@ -2405,8 +2405,10 @@ static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd)
int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
pmd_t *pmd, unsigned long addr)
{
pmd_t orig_pmd;
struct folio *folio = NULL;
int flush_needed = 1;
spinlock_t *ptl;
pmd_t orig_pmd;
tlb_change_page_size(tlb, HPAGE_PMD_SIZE);
@ -2427,59 +2429,60 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
if (arch_needs_pgtable_deposit())
zap_deposited_table(tlb->mm, pmd);
spin_unlock(ptl);
} else if (is_huge_zero_pmd(orig_pmd)) {
return 1;
}
if (is_huge_zero_pmd(orig_pmd)) {
if (!vma_is_dax(vma) || arch_needs_pgtable_deposit())
zap_deposited_table(tlb->mm, pmd);
spin_unlock(ptl);
} else {
struct folio *folio = NULL;
int flush_needed = 1;
if (pmd_present(orig_pmd)) {
struct page *page = pmd_page(orig_pmd);
folio = page_folio(page);
folio_remove_rmap_pmd(folio, page, vma);
WARN_ON_ONCE(folio_mapcount(folio) < 0);
VM_BUG_ON_PAGE(!PageHead(page), page);
} else if (pmd_is_valid_softleaf(orig_pmd)) {
const softleaf_t entry = softleaf_from_pmd(orig_pmd);
folio = softleaf_to_folio(entry);
flush_needed = 0;
if (!thp_migration_supported())
WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!");
}
if (folio_test_anon(folio)) {
zap_deposited_table(tlb->mm, pmd);
add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
} else {
if (arch_needs_pgtable_deposit())
zap_deposited_table(tlb->mm, pmd);
add_mm_counter(tlb->mm, mm_counter_file(folio),
-HPAGE_PMD_NR);
/*
* Use flush_needed to indicate whether the PMD entry
* is present, instead of checking pmd_present() again.
*/
if (flush_needed && pmd_young(orig_pmd) &&
likely(vma_has_recency(vma)))
folio_mark_accessed(folio);
}
if (folio_is_device_private(folio)) {
folio_remove_rmap_pmd(folio, &folio->page, vma);
WARN_ON_ONCE(folio_mapcount(folio) < 0);
folio_put(folio);
}
spin_unlock(ptl);
if (flush_needed)
tlb_remove_page_size(tlb, &folio->page, HPAGE_PMD_SIZE);
return 1;
}
if (pmd_present(orig_pmd)) {
struct page *page = pmd_page(orig_pmd);
folio = page_folio(page);
folio_remove_rmap_pmd(folio, page, vma);
WARN_ON_ONCE(folio_mapcount(folio) < 0);
VM_BUG_ON_PAGE(!PageHead(page), page);
} else if (pmd_is_valid_softleaf(orig_pmd)) {
const softleaf_t entry = softleaf_from_pmd(orig_pmd);
folio = softleaf_to_folio(entry);
flush_needed = 0;
if (!thp_migration_supported())
WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!");
}
if (folio_test_anon(folio)) {
zap_deposited_table(tlb->mm, pmd);
add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
} else {
if (arch_needs_pgtable_deposit())
zap_deposited_table(tlb->mm, pmd);
add_mm_counter(tlb->mm, mm_counter_file(folio),
-HPAGE_PMD_NR);
/*
* Use flush_needed to indicate whether the PMD entry
* is present, instead of checking pmd_present() again.
*/
if (flush_needed && pmd_young(orig_pmd) &&
likely(vma_has_recency(vma)))
folio_mark_accessed(folio);
}
if (folio_is_device_private(folio)) {
folio_remove_rmap_pmd(folio, &folio->page, vma);
WARN_ON_ONCE(folio_mapcount(folio) < 0);
folio_put(folio);
}
spin_unlock(ptl);
if (flush_needed)
tlb_remove_page_size(tlb, &folio->page, HPAGE_PMD_SIZE);
return 1;
}