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mm: introduce zap_nonpresent_ptes()

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Similar to zap_present_ptes(), let's introduce zap_nonpresent_ptes() to
handle non-present ptes, which can improve code readability.

No functional change.

Link: https://lkml.kernel.org/r/009ca882036d9c7a9f815489cfeafe0bdb79d62d.1733305182.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Jann Horn <jannh@google.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: Zach O'Keefe <zokeefe@google.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Qi Zheng 2024-12-04 19:09:43 +08:00 committed by Andrew Morton
parent 7f3440c80b
commit a9cdaa9f67
1 changed files with 73 additions and 63 deletions
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136
mm/memory.c
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@ -1587,6 +1587,76 @@ static inline int zap_present_ptes(struct mmu_gather *tlb,
return 1;
}
static inline int zap_nonpresent_ptes(struct mmu_gather *tlb,
struct vm_area_struct *vma, pte_t *pte, pte_t ptent,
unsigned int max_nr, unsigned long addr,
struct zap_details *details, int *rss)
{
swp_entry_t entry;
int nr = 1;
entry = pte_to_swp_entry(ptent);
if (is_device_private_entry(entry) ||
is_device_exclusive_entry(entry)) {
struct page *page = pfn_swap_entry_to_page(entry);
struct folio *folio = page_folio(page);
if (unlikely(!should_zap_folio(details, folio)))
return 1;
/*
* Both device private/exclusive mappings should only
* work with anonymous page so far, so we don't need to
* consider uffd-wp bit when zap. For more information,
* see zap_install_uffd_wp_if_needed().
*/
WARN_ON_ONCE(!vma_is_anonymous(vma));
rss[mm_counter(folio)]--;
if (is_device_private_entry(entry))
folio_remove_rmap_pte(folio, page, vma);
folio_put(folio);
} else if (!non_swap_entry(entry)) {
/* Genuine swap entries, hence a private anon pages */
if (!should_zap_cows(details))
return 1;
nr = swap_pte_batch(pte, max_nr, ptent);
rss[MM_SWAPENTS] -= nr;
free_swap_and_cache_nr(entry, nr);
} else if (is_migration_entry(entry)) {
struct folio *folio = pfn_swap_entry_folio(entry);
if (!should_zap_folio(details, folio))
return 1;
rss[mm_counter(folio)]--;
} else if (pte_marker_entry_uffd_wp(entry)) {
/*
* For anon: always drop the marker; for file: only
* drop the marker if explicitly requested.
*/
if (!vma_is_anonymous(vma) && !zap_drop_markers(details))
return 1;
} else if (is_guard_swp_entry(entry)) {
/*
* Ordinary zapping should not remove guard PTE
* markers. Only do so if we should remove PTE markers
* in general.
*/
if (!zap_drop_markers(details))
return 1;
} else if (is_hwpoison_entry(entry) || is_poisoned_swp_entry(entry)) {
if (!should_zap_cows(details))
return 1;
} else {
/* We should have covered all the swap entry types */
pr_alert("unrecognized swap entry 0x%lx\n", entry.val);
WARN_ON_ONCE(1);
}
clear_not_present_full_ptes(vma->vm_mm, addr, pte, nr, tlb->fullmm);
zap_install_uffd_wp_if_needed(vma, addr, pte, nr, details, ptent);
return nr;
}
static unsigned long zap_pte_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, unsigned long end,
@ -1598,7 +1668,6 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
spinlock_t *ptl;
pte_t *start_pte;
pte_t *pte;
swp_entry_t entry;
int nr;
tlb_change_page_size(tlb, PAGE_SIZE);
@ -1611,8 +1680,6 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
arch_enter_lazy_mmu_mode();
do {
pte_t ptent = ptep_get(pte);
struct folio *folio;
struct page *page;
int max_nr;
nr = 1;
@ -1622,8 +1689,8 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
if (need_resched())
break;
max_nr = (end - addr) / PAGE_SIZE;
if (pte_present(ptent)) {
max_nr = (end - addr) / PAGE_SIZE;
nr = zap_present_ptes(tlb, vma, pte, ptent, max_nr,
addr, details, rss, &force_flush,
&force_break);
@ -1631,67 +1698,10 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
addr += nr * PAGE_SIZE;
break;
}
continue;
}
entry = pte_to_swp_entry(ptent);
if (is_device_private_entry(entry) ||
is_device_exclusive_entry(entry)) {
page = pfn_swap_entry_to_page(entry);
folio = page_folio(page);
if (unlikely(!should_zap_folio(details, folio)))
continue;
/*
* Both device private/exclusive mappings should only
* work with anonymous page so far, so we don't need to
* consider uffd-wp bit when zap. For more information,
* see zap_install_uffd_wp_if_needed().
*/
WARN_ON_ONCE(!vma_is_anonymous(vma));
rss[mm_counter(folio)]--;
if (is_device_private_entry(entry))
folio_remove_rmap_pte(folio, page, vma);
folio_put(folio);
} else if (!non_swap_entry(entry)) {
max_nr = (end - addr) / PAGE_SIZE;
nr = swap_pte_batch(pte, max_nr, ptent);
/* Genuine swap entries, hence a private anon pages */
if (!should_zap_cows(details))
continue;
rss[MM_SWAPENTS] -= nr;
free_swap_and_cache_nr(entry, nr);
} else if (is_migration_entry(entry)) {
folio = pfn_swap_entry_folio(entry);
if (!should_zap_folio(details, folio))
continue;
rss[mm_counter(folio)]--;
} else if (pte_marker_entry_uffd_wp(entry)) {
/*
* For anon: always drop the marker; for file: only
* drop the marker if explicitly requested.
*/
if (!vma_is_anonymous(vma) &&
!zap_drop_markers(details))
continue;
} else if (is_guard_swp_entry(entry)) {
/*
* Ordinary zapping should not remove guard PTE
* markers. Only do so if we should remove PTE markers
* in general.
*/
if (!zap_drop_markers(details))
continue;
} else if (is_hwpoison_entry(entry) ||
is_poisoned_swp_entry(entry)) {
if (!should_zap_cows(details))
continue;
} else {
/* We should have covered all the swap entry types */
pr_alert("unrecognized swap entry 0x%lx\n", entry.val);
WARN_ON_ONCE(1);
nr = zap_nonpresent_ptes(tlb, vma, pte, ptent, max_nr,
addr, details, rss);
}
clear_not_present_full_ptes(mm, addr, pte, nr, tlb->fullmm);
zap_install_uffd_wp_if_needed(vma, addr, pte, nr, details, ptent);
} while (pte += nr, addr += PAGE_SIZE * nr, addr != end);
add_mm_rss_vec(mm, rss);