mm: swapoff: shmem_find_swap_entries() filter out other types (87039546) · Commits · 戴 / test

Swapfile "type" was passed all the way down to shmem_unuse_inode(), but then forgotten from shmem_find_swap_entries(): with the result that removing one swapfile would try to free up all the swap from shmem - no problem when only one swapfile anyway, but counter-productive when more, causing swapoff to be unnecessarily OOM-killed when it should succeed. Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1904081254470.1523@eggly.anvils Fixes: ("mm: rid swapoff of quadratic complexity") Signed-off-by:

Hugh Dickins <hughd@google.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: "Alex Xu (Hello71)" <alex_y_xu@yahoo.ca> Cc: Vineeth Pillai <vpillai@digitalocean.com> Cc: Kelley Nielsen <kelleynnn@gmail.com> Cc: Rik van Riel <riel@surriel.com> Cc: Huang Ying <ying.huang@intel.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/shmem.c

+9 −9

Original line number	Diff line number	Diff line
		@@ -1099,10 +1099,11 @@ extern struct swap_info_struct *swap_info[];
		static int shmem_find_swap_entries(struct address_space *mapping,
		pgoff_t start, unsigned int nr_entries,
		struct page *entries, pgoff_t indices,
		bool frontswap)
		unsigned int type, bool frontswap)
		{
		XA_STATE(xas, &mapping->i_pages, start);
		struct page *page;
		swp_entry_t entry;
		unsigned int ret = 0;

		if (!nr_entries)
		@@ -1116,13 +1117,12 @@ static int shmem_find_swap_entries(struct address_space *mapping,
		if (!xa_is_value(page))
		continue;

		if (frontswap) {
		swp_entry_t entry = radix_to_swp_entry(page);

		if (!frontswap_test(swap_info[swp_type(entry)],
		swp_offset(entry)))
		entry = radix_to_swp_entry(page);
		if (swp_type(entry) != type)
		continue;
		if (frontswap &&
		!frontswap_test(swap_info[type], swp_offset(entry)))
		continue;
		}

		indices[ret] = xas.xa_index;
		entries[ret] = page;
		@@ -1194,7 +1194,7 @@ static int shmem_unuse_inode(struct inode *inode, unsigned int type,

		pvec.nr = shmem_find_swap_entries(mapping, start, nr_entries,
		pvec.pages, indices,
		frontswap);
		type, frontswap);
		if (pvec.nr == 0) {
		ret = 0;
		break;

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