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authorMatthew Wilcox (Oracle) <willy@infradead.org>2020-10-13 16:51:24 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-13 18:38:29 -0700
commite6e88712e43b7942df451508aafc2f083266f56b (patch)
treeee72fadc853f21222d73acc482f343bac49df7f6
parentf5df8635c5a3c912919c91be64aa198554b0f9ed (diff)
mm: optimise madvise WILLNEED
Instead of calling find_get_entry() for every page index, use an XArray iterator to skip over NULL entries, and avoid calling get_page(), because we only want the swap entries. [willy@infradead.org: fix LTP soft lockups] Link: https://lkml.kernel.org/r/20200914165032.GS6583@casper.infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Huang Ying <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Matthew Auld <matthew.auld@intel.com> Cc: William Kucharski <william.kucharski@oracle.com> Cc: Qian Cai <cai@redhat.com> Link: https://lkml.kernel.org/r/20200910183318.20139-4-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/madvise.c21
1 files changed, 12 insertions, 9 deletions
diff --git a/mm/madvise.c b/mm/madvise.c
index 0e0d61003fc6..9b065d412e5f 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -224,25 +224,28 @@ static void force_shm_swapin_readahead(struct vm_area_struct *vma,
unsigned long start, unsigned long end,
struct address_space *mapping)
{
- pgoff_t index;
+ XA_STATE(xas, &mapping->i_pages, linear_page_index(vma, start));
+ pgoff_t end_index = end / PAGE_SIZE;
struct page *page;
- swp_entry_t swap;
- for (; start < end; start += PAGE_SIZE) {
- index = ((start - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+ rcu_read_lock();
+ xas_for_each(&xas, page, end_index) {
+ swp_entry_t swap;
- page = find_get_entry(mapping, index);
- if (!xa_is_value(page)) {
- if (page)
- put_page(page);
+ if (!xa_is_value(page))
continue;
- }
+ xas_pause(&xas);
+ rcu_read_unlock();
+
swap = radix_to_swp_entry(page);
page = read_swap_cache_async(swap, GFP_HIGHUSER_MOVABLE,
NULL, 0, false);
if (page)
put_page(page);
+
+ rcu_read_lock();
}
+ rcu_read_unlock();
lru_add_drain(); /* Push any new pages onto the LRU now */
}