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mm: perform async writes to SWP_FS_OPS swap-space using ->swap_rw
This patch switches swap-out to SWP_FS_OPS swap-spaces to use ->swap_rw and makes the writes asynchronous, like they are for other swap spaces. To make it async we need to allocate the kiocb struct from a mempool. This may block, but won't block as long as waiting for the write to complete. At most it will wait for some previous swap IO to complete. Link: https://lkml.kernel.org/r/164859778126.29473.12399585304843922231.stgit@noble.brown Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: David Howells <dhowells@redhat.com> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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eb79f3af93
commit
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1 changed files with 58 additions and 40 deletions
98
mm/page_io.c
98
mm/page_io.c
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@ -254,6 +254,57 @@ int sio_pool_init(void)
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return 0;
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return 0;
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}
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}
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static void sio_write_complete(struct kiocb *iocb, long ret)
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{
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struct swap_iocb *sio = container_of(iocb, struct swap_iocb, iocb);
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struct page *page = sio->bvec.bv_page;
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if (ret != PAGE_SIZE) {
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/*
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* In the case of swap-over-nfs, this can be a
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* temporary failure if the system has limited
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* memory for allocating transmit buffers.
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* Mark the page dirty and avoid
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* folio_rotate_reclaimable but rate-limit the
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* messages but do not flag PageError like
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* the normal direct-to-bio case as it could
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* be temporary.
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*/
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set_page_dirty(page);
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ClearPageReclaim(page);
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pr_err_ratelimited("Write error %ld on dio swapfile (%llu)\n",
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ret, page_file_offset(page));
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} else
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count_vm_event(PSWPOUT);
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end_page_writeback(page);
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mempool_free(sio, sio_pool);
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}
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static int swap_writepage_fs(struct page *page, struct writeback_control *wbc)
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{
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struct swap_iocb *sio;
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struct swap_info_struct *sis = page_swap_info(page);
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struct file *swap_file = sis->swap_file;
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struct address_space *mapping = swap_file->f_mapping;
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struct iov_iter from;
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int ret;
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set_page_writeback(page);
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unlock_page(page);
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sio = mempool_alloc(sio_pool, GFP_NOIO);
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init_sync_kiocb(&sio->iocb, swap_file);
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sio->iocb.ki_complete = sio_write_complete;
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sio->iocb.ki_pos = page_file_offset(page);
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sio->bvec.bv_page = page;
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sio->bvec.bv_len = PAGE_SIZE;
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sio->bvec.bv_offset = 0;
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iov_iter_bvec(&from, WRITE, &sio->bvec, 1, PAGE_SIZE);
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ret = mapping->a_ops->swap_rw(&sio->iocb, &from);
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if (ret != -EIOCBQUEUED)
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sio_write_complete(&sio->iocb, ret);
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return ret;
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}
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int __swap_writepage(struct page *page, struct writeback_control *wbc,
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int __swap_writepage(struct page *page, struct writeback_control *wbc,
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bio_end_io_t end_write_func)
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bio_end_io_t end_write_func)
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{
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{
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@ -262,46 +313,13 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc,
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struct swap_info_struct *sis = page_swap_info(page);
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struct swap_info_struct *sis = page_swap_info(page);
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VM_BUG_ON_PAGE(!PageSwapCache(page), page);
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VM_BUG_ON_PAGE(!PageSwapCache(page), page);
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if (data_race(sis->flags & SWP_FS_OPS)) {
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/*
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struct kiocb kiocb;
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* ->flags can be updated non-atomicially (scan_swap_map_slots),
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struct file *swap_file = sis->swap_file;
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* but that will never affect SWP_FS_OPS, so the data_race
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struct address_space *mapping = swap_file->f_mapping;
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* is safe.
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struct bio_vec bv = {
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*/
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.bv_page = page,
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if (data_race(sis->flags & SWP_FS_OPS))
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.bv_len = PAGE_SIZE,
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return swap_writepage_fs(page, wbc);
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.bv_offset = 0
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};
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struct iov_iter from;
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iov_iter_bvec(&from, WRITE, &bv, 1, PAGE_SIZE);
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init_sync_kiocb(&kiocb, swap_file);
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kiocb.ki_pos = page_file_offset(page);
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set_page_writeback(page);
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unlock_page(page);
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ret = mapping->a_ops->direct_IO(&kiocb, &from);
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if (ret == PAGE_SIZE) {
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count_vm_event(PSWPOUT);
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ret = 0;
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} else {
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/*
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* In the case of swap-over-nfs, this can be a
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* temporary failure if the system has limited
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* memory for allocating transmit buffers.
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* Mark the page dirty and avoid
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* folio_rotate_reclaimable but rate-limit the
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* messages but do not flag PageError like
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* the normal direct-to-bio case as it could
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* be temporary.
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*/
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set_page_dirty(page);
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ClearPageReclaim(page);
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pr_err_ratelimited("Write error on dio swapfile (%llu)\n",
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page_file_offset(page));
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}
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end_page_writeback(page);
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return ret;
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}
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ret = bdev_write_page(sis->bdev, swap_page_sector(page), page, wbc);
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ret = bdev_write_page(sis->bdev, swap_page_sector(page), page, wbc);
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if (!ret) {
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if (!ret) {
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