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authorLinus Torvalds <torvalds@linux-foundation.org>2016-01-15 22:41:44 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-15 22:41:44 +0300
commit875fc4f5ddf35605581f9a5900c14afef48611f2 (patch)
treee237a28a71a5d1e72eaf0ecda737eb5c8614c72c /mm/shmem.c
parent7d1fc01afc5af35e5197e0e75abe900f6bd279b8 (diff)
parent7dfa4612204b511c934ca2a0e4f306f9981bd9aa (diff)
downloadlinux-875fc4f5ddf35605581f9a5900c14afef48611f2.tar.xz
Merge branch 'akpm' (patches from Andrew)
Merge first patch-bomb from Andrew Morton: - A few hotfixes which missed 4.4 becasue I was asleep. cc'ed to -stable - A few misc fixes - OCFS2 updates - Part of MM. Including pretty large changes to page-flags handling and to thp management which have been buffered up for 2-3 cycles now. I have a lot of MM material this time. [ It turns out the THP part wasn't quite ready, so that got dropped from this series - Linus ] * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (117 commits) zsmalloc: reorganize struct size_class to pack 4 bytes hole mm/zbud.c: use list_last_entry() instead of list_tail_entry() zram/zcomp: do not zero out zcomp private pages zram: pass gfp from zcomp frontend to backend zram: try vmalloc() after kmalloc() zram/zcomp: use GFP_NOIO to allocate streams mm: add tracepoint for scanning pages drivers/base/memory.c: fix kernel warning during memory hotplug on ppc64 mm/page_isolation: use macro to judge the alignment mm: fix noisy sparse warning in LIBCFS_ALLOC_PRE() mm: rework virtual memory accounting include/linux/memblock.h: fix ordering of 'flags' argument in comments mm: move lru_to_page to mm_inline.h Documentation/filesystems: describe the shared memory usage/accounting memory-hotplug: don't BUG() in register_memory_resource() hugetlb: make mm and fs code explicitly non-modular mm/swapfile.c: use list_for_each_entry_safe in free_swap_count_continuations mm: /proc/pid/clear_refs: no need to clear VM_SOFTDIRTY in clear_soft_dirty_pmd() mm: make sure isolate_lru_page() is never called for tail page vmstat: make vmstat_updater deferrable again and shut down on idle ...
Diffstat (limited to 'mm/shmem.c')
-rw-r--r--mm/shmem.c83
1 files changed, 82 insertions, 1 deletions
diff --git a/mm/shmem.c b/mm/shmem.c
index 642471b0ddea..970ff5b80853 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -360,6 +360,87 @@ static int shmem_free_swap(struct address_space *mapping,
}
/*
+ * Determine (in bytes) how many of the shmem object's pages mapped by the
+ * given offsets are swapped out.
+ *
+ * This is safe to call without i_mutex or mapping->tree_lock thanks to RCU,
+ * as long as the inode doesn't go away and racy results are not a problem.
+ */
+unsigned long shmem_partial_swap_usage(struct address_space *mapping,
+ pgoff_t start, pgoff_t end)
+{
+ struct radix_tree_iter iter;
+ void **slot;
+ struct page *page;
+ unsigned long swapped = 0;
+
+ rcu_read_lock();
+
+restart:
+ radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
+ if (iter.index >= end)
+ break;
+
+ page = radix_tree_deref_slot(slot);
+
+ /*
+ * This should only be possible to happen at index 0, so we
+ * don't need to reset the counter, nor do we risk infinite
+ * restarts.
+ */
+ if (radix_tree_deref_retry(page))
+ goto restart;
+
+ if (radix_tree_exceptional_entry(page))
+ swapped++;
+
+ if (need_resched()) {
+ cond_resched_rcu();
+ start = iter.index + 1;
+ goto restart;
+ }
+ }
+
+ rcu_read_unlock();
+
+ return swapped << PAGE_SHIFT;
+}
+
+/*
+ * Determine (in bytes) how many of the shmem object's pages mapped by the
+ * given vma is swapped out.
+ *
+ * This is safe to call without i_mutex or mapping->tree_lock thanks to RCU,
+ * as long as the inode doesn't go away and racy results are not a problem.
+ */
+unsigned long shmem_swap_usage(struct vm_area_struct *vma)
+{
+ struct inode *inode = file_inode(vma->vm_file);
+ struct shmem_inode_info *info = SHMEM_I(inode);
+ struct address_space *mapping = inode->i_mapping;
+ unsigned long swapped;
+
+ /* Be careful as we don't hold info->lock */
+ swapped = READ_ONCE(info->swapped);
+
+ /*
+ * The easier cases are when the shmem object has nothing in swap, or
+ * the vma maps it whole. Then we can simply use the stats that we
+ * already track.
+ */
+ if (!swapped)
+ return 0;
+
+ if (!vma->vm_pgoff && vma->vm_end - vma->vm_start >= inode->i_size)
+ return swapped << PAGE_SHIFT;
+
+ /* Here comes the more involved part */
+ return shmem_partial_swap_usage(mapping,
+ linear_page_index(vma, vma->vm_start),
+ linear_page_index(vma, vma->vm_end));
+}
+
+/*
* SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists.
*/
void shmem_unlock_mapping(struct address_space *mapping)
@@ -3064,7 +3145,7 @@ static int shmem_init_inodecache(void)
{
shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
sizeof(struct shmem_inode_info),
- 0, SLAB_PANIC, shmem_init_inode);
+ 0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode);
return 0;
}