From: Zi Yan <ziy@xxxxxxxxxx>
Both src and dst page lists should match the page size at each
page and the length of both lists is shared.
Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
---
mm/copy_pages.c | 158 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
mm/internal.h | 3 ++
mm/migrate.c | 5 +-
3 files changed, 165 insertions(+), 1 deletion(-)
diff --git a/mm/copy_pages.c b/mm/copy_pages.c
index f135bf505183..cf674840a830 100644
--- a/mm/copy_pages.c
+++ b/mm/copy_pages.c
@@ -560,3 +560,161 @@ int copy_page_dma(struct page *to, struct page *from, int nr_pages)
return copy_page_dma_always(to, from, nr_pages);
}
+
+/*
+ * Use DMA copy a list of pages to a new location
+ *
+ * Just put each page into individual DMA channel.
+ *
+ * */
+int copy_page_lists_dma_always(struct page **to, struct page **from, int nr_pages)
+{
+ struct dma_async_tx_descriptor **tx = NULL;
+ dma_cookie_t *cookie = NULL;
+ enum dma_ctrl_flags flags[NUM_AVAIL_DMA_CHAN] = {0};
+ struct dmaengine_unmap_data *unmap[NUM_AVAIL_DMA_CHAN] = {0};
+ int ret_val = 0;
+ int total_available_chans = NUM_AVAIL_DMA_CHAN;
+ int i;
+
+ for (i = 0; i < NUM_AVAIL_DMA_CHAN; ++i) {
+ if (!copy_chan[i])
+ total_available_chans = i;
+ }
+ if (total_available_chans != NUM_AVAIL_DMA_CHAN)
+ pr_err("%d channels are missing\n", NUM_AVAIL_DMA_CHAN - total_available_chans);
+
+ if (limit_dma_chans < total_available_chans)
+ total_available_chans = limit_dma_chans;
+
+ /* round down to closest 2^x value */
+ total_available_chans = 1<<ilog2(total_available_chans);
+
+ total_available_chans = min_t(int, total_available_chans, nr_pages);
+
+
+ tx = kzalloc(sizeof(struct dma_async_tx_descriptor*)*nr_pages, GFP_KERNEL);
+ if (!tx) {
+ ret_val = -ENOMEM;
+ goto out;
+ }
+ cookie = kzalloc(sizeof(dma_cookie_t)*nr_pages, GFP_KERNEL);
+ if (!cookie) {
+ ret_val = -ENOMEM;
+ goto out_free_tx;
+ }
+
+
+ for (i = 0; i < total_available_chans; ++i) {
+ int num_xfer_per_dev = nr_pages / total_available_chans;
+
+ if (i < (nr_pages % total_available_chans))
+ num_xfer_per_dev += 1;
+
+ unmap[i] = dmaengine_get_unmap_data(copy_dev[i]->dev,
+ 2*num_xfer_per_dev, GFP_NOWAIT);
+ if (!unmap[i]) {
+ pr_err("%s: no unmap data at chan %d\n", __func__, i);
+ ret_val = -ENODEV;
+ goto unmap_dma;
+ }
+ }
+
+ for (i = 0; i < total_available_chans; ++i) {
+ int num_xfer_per_dev = nr_pages / total_available_chans;
+ int xfer_idx;
+
+ if (i < (nr_pages % total_available_chans))
+ num_xfer_per_dev += 1;
+
+ unmap[i]->to_cnt = num_xfer_per_dev;
+ unmap[i]->from_cnt = num_xfer_per_dev;
+ unmap[i]->len = hpage_nr_pages(from[i]) * PAGE_SIZE;
+
+ for (xfer_idx = 0; xfer_idx < num_xfer_per_dev; ++xfer_idx) {
+ int page_idx = i + xfer_idx * total_available_chans;
+ size_t page_len = hpage_nr_pages(from[page_idx]) * PAGE_SIZE;
+
+ BUG_ON(page_len != hpage_nr_pages(to[page_idx]) * PAGE_SIZE);
+ BUG_ON(unmap[i]->len != page_len);
+
+ unmap[i]->addr[xfer_idx] =
+ dma_map_page(copy_dev[i]->dev, from[page_idx],
+ 0,
+ page_len,
+ DMA_TO_DEVICE);
+
+ unmap[i]->addr[xfer_idx+num_xfer_per_dev] =
+ dma_map_page(copy_dev[i]->dev, to[page_idx],
+ 0,
+ page_len,
+ DMA_FROM_DEVICE);
+ }
+ }
+
+ for (i = 0; i < total_available_chans; ++i) {
+ int num_xfer_per_dev = nr_pages / total_available_chans;
+ int xfer_idx;
+
+ if (i < (nr_pages % total_available_chans))
+ num_xfer_per_dev += 1;
+
+ for (xfer_idx = 0; xfer_idx < num_xfer_per_dev; ++xfer_idx) {
+ int page_idx = i + xfer_idx * total_available_chans;
+
+ tx[page_idx] = copy_dev[i]->device_prep_dma_memcpy(copy_chan[i],
+ unmap[i]->addr[xfer_idx + num_xfer_per_dev],
+ unmap[i]->addr[xfer_idx],
+ unmap[i]->len,
+ flags[i]);
+ if (!tx[page_idx]) {
+ pr_err("%s: no tx descriptor at chan %d xfer %d\n",
+ __func__, i, xfer_idx);
+ ret_val = -ENODEV;
+ goto unmap_dma;
+ }
+
+ cookie[page_idx] = tx[page_idx]->tx_submit(tx[page_idx]);
+
+ if (dma_submit_error(cookie[page_idx])) {
+ pr_err("%s: submission error at chan %d xfer %d\n",
+ __func__, i, xfer_idx);
+ ret_val = -ENODEV;
+ goto unmap_dma;
+ }
+ }
+
+ dma_async_issue_pending(copy_chan[i]);
+ }
+
+ for (i = 0; i < total_available_chans; ++i) {
+ int num_xfer_per_dev = nr_pages / total_available_chans;
+ int xfer_idx;
+
+ if (i < (nr_pages % total_available_chans))
+ num_xfer_per_dev += 1;
+
+ for (xfer_idx = 0; xfer_idx < num_xfer_per_dev; ++xfer_idx) {
+ int page_idx = i + xfer_idx * total_available_chans;
+
+ if (dma_sync_wait(copy_chan[i], cookie[page_idx]) != DMA_COMPLETE) {
+ ret_val = -EFAULT;
+ pr_err("%s: dma does not complete at chan %d, xfer %d\n",
+ __func__, i, xfer_idx);
+ }
+ }
+ }
+
+unmap_dma:
+ for (i = 0; i < total_available_chans; ++i) {
+ if (unmap[i])
+ dmaengine_unmap_put(unmap[i]);
+ }
+
+ kfree(cookie);
+out_free_tx:
+ kfree(tx);
+out:
+
+ return ret_val;
+}
diff --git a/mm/internal.h b/mm/internal.h
index b99a634b4d09..32048e89bfda 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -500,10 +500,13 @@ extern const struct trace_print_flags gfpflag_names[];
extern int copy_page_lists_mthread(struct page **to,
struct page **from, int nr_pages);
+extern int copy_page_lists_dma_always(struct page **to,
+ struct page **from, int nr_pages);
extern int exchange_page_mthread(struct page *to, struct page *from,
int nr_pages);
extern int exchange_page_lists_mthread(struct page **to,
struct page **from,
int nr_pages);
+
#endif /* __MM_INTERNAL_H */
diff --git a/mm/migrate.c b/mm/migrate.c
index 464bc9ba8083..63e44ac65184 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1611,7 +1611,10 @@ static int copy_to_new_pages_concur(struct list_head *unmapped_list_ptr,
BUG_ON(idx != num_pages);
- if (mode & MIGRATE_MT)
+ if (mode & MIGRATE_DMA)
+ rc = copy_page_lists_dma_always(dst_page_list, src_page_list,
+ num_pages);
+ else if (mode & MIGRATE_MT)
rc = copy_page_lists_mthread(dst_page_list, src_page_list,
num_pages);
--
2.11.0
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