From: Hugh Dickins <hughd@xxxxxxxxxx> Subject: mm: swapoff: shmem_find_swap_entries() filter out other types 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: b56a2d8af914 ("mm: rid swapoff of quadratic complexity") Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx> Cc: "Alex Xu (Hello71)" <alex_y_xu@xxxxxxxx> Cc: Vineeth Pillai <vpillai@xxxxxxxxxxxxxxxx> Cc: Kelley Nielsen <kelleynnn@xxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxxx> Cc: Huang Ying <ying.huang@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/shmem.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) --- a/mm/shmem.c~mm-swapoff-shmem_find_swap_entries-filter-out-other-types +++ a/mm/shmem.c @@ -1099,10 +1099,11 @@ extern struct swap_info_struct *swap_inf 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(struc 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))) - continue; - } + 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 inod pvec.nr = shmem_find_swap_entries(mapping, start, nr_entries, pvec.pages, indices, - frontswap); + type, frontswap); if (pvec.nr == 0) { ret = 0; break; _
