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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2015-02-10 14:09:49 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-02-10 14:30:30 -0800
commit8a5f14a23177061ec11daeaa3d09d0765d785c47 (patch)
tree5199ffd75455cc98b652767813d07e64e6895c4e /mm/memory.c
parentc8d78c1823f46519473949d33f0d1d33fe21ea16 (diff)
mm: drop support of non-linear mapping from unmap/zap codepath
We have remap_file_pages(2) emulation in -mm tree for few release cycles and we plan to have it mainline in v3.20. This patchset removes rest of VM_NONLINEAR infrastructure. Patches 1-8 take care about generic code. They are pretty straight-forward and can be applied without other of patches. Rest patches removes pte_file()-related stuff from architecture-specific code. It usually frees up one bit in non-present pte. I've tried to reuse that bit for swap offset, where I was able to figure out how to do that. For obvious reason I cannot test all that arch-specific code and would like to see acks from maintainers. In total, remap_file_pages(2) required about 1.4K lines of not-so-trivial kernel code. That's too much for functionality nobody uses. Tested-by: Felipe Balbi <balbi@ti.com> This patch (of 38): We don't create non-linear mappings anymore. Let's drop code which handles them on unmap/zap. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c82
1 files changed, 21 insertions, 61 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 2c3536cc6c63..9a3e73b69dad 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1082,6 +1082,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
spinlock_t *ptl;
pte_t *start_pte;
pte_t *pte;
+ swp_entry_t entry;
again:
init_rss_vec(rss);
@@ -1107,28 +1108,12 @@ again:
if (details->check_mapping &&
details->check_mapping != page->mapping)
continue;
- /*
- * Each page->index must be checked when
- * invalidating or truncating nonlinear.
- */
- if (details->nonlinear_vma &&
- (page->index < details->first_index ||
- page->index > details->last_index))
- continue;
}
ptent = ptep_get_and_clear_full(mm, addr, pte,
tlb->fullmm);
tlb_remove_tlb_entry(tlb, pte, addr);
if (unlikely(!page))
continue;
- if (unlikely(details) && details->nonlinear_vma
- && linear_page_index(details->nonlinear_vma,
- addr) != page->index) {
- pte_t ptfile = pgoff_to_pte(page->index);
- if (pte_soft_dirty(ptent))
- ptfile = pte_file_mksoft_dirty(ptfile);
- set_pte_at(mm, addr, pte, ptfile);
- }
if (PageAnon(page))
rss[MM_ANONPAGES]--;
else {
@@ -1151,33 +1136,25 @@ again:
}
continue;
}
- /*
- * If details->check_mapping, we leave swap entries;
- * if details->nonlinear_vma, we leave file entries.
- */
+ /* If details->check_mapping, we leave swap entries. */
if (unlikely(details))
continue;
- if (pte_file(ptent)) {
- if (unlikely(!(vma->vm_flags & VM_NONLINEAR)))
- print_bad_pte(vma, addr, ptent, NULL);
- } else {
- swp_entry_t entry = pte_to_swp_entry(ptent);
- if (!non_swap_entry(entry))
- rss[MM_SWAPENTS]--;
- else if (is_migration_entry(entry)) {
- struct page *page;
+ entry = pte_to_swp_entry(ptent);
+ if (!non_swap_entry(entry))
+ rss[MM_SWAPENTS]--;
+ else if (is_migration_entry(entry)) {
+ struct page *page;
- page = migration_entry_to_page(entry);
+ page = migration_entry_to_page(entry);
- if (PageAnon(page))
- rss[MM_ANONPAGES]--;
- else
- rss[MM_FILEPAGES]--;
- }
- if (unlikely(!free_swap_and_cache(entry)))
- print_bad_pte(vma, addr, ptent, NULL);
+ if (PageAnon(page))
+ rss[MM_ANONPAGES]--;
+ else
+ rss[MM_FILEPAGES]--;
}
+ if (unlikely(!free_swap_and_cache(entry)))
+ print_bad_pte(vma, addr, ptent, NULL);
pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
} while (pte++, addr += PAGE_SIZE, addr != end);
@@ -1277,7 +1254,7 @@ static void unmap_page_range(struct mmu_gather *tlb,
pgd_t *pgd;
unsigned long next;
- if (details && !details->check_mapping && !details->nonlinear_vma)
+ if (details && !details->check_mapping)
details = NULL;
BUG_ON(addr >= end);
@@ -1371,7 +1348,7 @@ void unmap_vmas(struct mmu_gather *tlb,
* @vma: vm_area_struct holding the applicable pages
* @start: starting address of pages to zap
* @size: number of bytes to zap
- * @details: details of nonlinear truncation or shared cache invalidation
+ * @details: details of shared cache invalidation
*
* Caller must protect the VMA list
*/
@@ -1397,7 +1374,7 @@ void zap_page_range(struct vm_area_struct *vma, unsigned long start,
* @vma: vm_area_struct holding the applicable pages
* @address: starting address of pages to zap
* @size: number of bytes to zap
- * @details: details of nonlinear truncation or shared cache invalidation
+ * @details: details of shared cache invalidation
*
* The range must fit into one VMA.
*/
@@ -2331,25 +2308,11 @@ static inline void unmap_mapping_range_tree(struct rb_root *root,
}
}
-static inline void unmap_mapping_range_list(struct list_head *head,
- struct zap_details *details)
-{
- struct vm_area_struct *vma;
-
- /*
- * In nonlinear VMAs there is no correspondence between virtual address
- * offset and file offset. So we must perform an exhaustive search
- * across *all* the pages in each nonlinear VMA, not just the pages
- * whose virtual address lies outside the file truncation point.
- */
- list_for_each_entry(vma, head, shared.nonlinear) {
- details->nonlinear_vma = vma;
- unmap_mapping_range_vma(vma, vma->vm_start, vma->vm_end, details);
- }
-}
-
/**
- * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
+ * unmap_mapping_range - unmap the portion of all mmaps in the specified
+ * address_space corresponding to the specified page range in the underlying
+ * file.
+ *
* @mapping: the address space containing mmaps to be unmapped.
* @holebegin: byte in first page to unmap, relative to the start of
* the underlying file. This will be rounded down to a PAGE_SIZE
@@ -2378,7 +2341,6 @@ void unmap_mapping_range(struct address_space *mapping,
}
details.check_mapping = even_cows? NULL: mapping;
- details.nonlinear_vma = NULL;
details.first_index = hba;
details.last_index = hba + hlen - 1;
if (details.last_index < details.first_index)
@@ -2388,8 +2350,6 @@ void unmap_mapping_range(struct address_space *mapping,
i_mmap_lock_write(mapping);
if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap)))
unmap_mapping_range_tree(&mapping->i_mmap, &details);
- if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
- unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
i_mmap_unlock_write(mapping);
}
EXPORT_SYMBOL(unmap_mapping_range);