mm: introduce page reference manipulation functions
The success of CMA allocation largely depends on the success of
migration and key factor of it is page reference count. Until now, page
reference is manipulated by direct calling atomic functions so we cannot
follow up who and where manipulate it. Then, it is hard to find actual
reason of CMA allocation failure. CMA allocation should be guaranteed
to succeed so finding offending place is really important.
In this patch, call sites where page reference is manipulated are
converted to introduced wrapper function. This is preparation step to
add tracepoint to each page reference manipulation function. With this
facility, we can easily find reason of CMA allocation failure. There is
no functional change in this patch.
In addition, this patch also converts reference read sites. It will
help a second step that renames page._count to something else and
prevents later attempt to direct access to it (Suggested by Andrew).
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c
index b9ecf19..f21b2c4 100644
--- a/drivers/net/ethernet/freescale/gianfar.c
+++ b/drivers/net/ethernet/freescale/gianfar.c
@@ -2944,7 +2944,7 @@
/* change offset to the other half */
rxb->page_offset ^= GFAR_RXB_TRUESIZE;
- atomic_inc(&page->_count);
+ page_ref_inc(page);
return true;
}
diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_main.c b/drivers/net/ethernet/intel/fm10k/fm10k_main.c
index b243c3c..b4547eb 100644
--- a/drivers/net/ethernet/intel/fm10k/fm10k_main.c
+++ b/drivers/net/ethernet/intel/fm10k/fm10k_main.c
@@ -243,7 +243,7 @@
/* Even if we own the page, we are not allowed to use atomic_set()
* This would break get_page_unless_zero() users.
*/
- atomic_inc(&page->_count);
+ page_ref_inc(page);
return true;
}
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 31e5f39..5b4ad1a 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -6630,7 +6630,7 @@
/* Even if we own the page, we are not allowed to use atomic_set()
* This would break get_page_unless_zero() users.
*/
- atomic_inc(&page->_count);
+ page_ref_inc(page);
return true;
}
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index c4003a8..e6035ff 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -1942,7 +1942,7 @@
/* Even if we own the page, we are not allowed to use atomic_set()
* This would break get_page_unless_zero() users.
*/
- atomic_inc(&page->_count);
+ page_ref_inc(page);
return true;
}
diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index 3558f01..0ea14c0 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -837,7 +837,7 @@
/* Even if we own the page, we are not allowed to use atomic_set()
* This would break get_page_unless_zero() users.
*/
- atomic_inc(&page->_count);
+ page_ref_inc(page);
return true;
}
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
index 41440b2..86bcfe5 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
@@ -82,8 +82,7 @@
/* Not doing get_page() for each frag is a big win
* on asymetric workloads. Note we can not use atomic_set().
*/
- atomic_add(page_alloc->page_size / frag_info->frag_stride - 1,
- &page->_count);
+ page_ref_add(page, page_alloc->page_size / frag_info->frag_stride - 1);
return 0;
}
@@ -127,7 +126,7 @@
dma_unmap_page(priv->ddev, page_alloc[i].dma,
page_alloc[i].page_size, PCI_DMA_FROMDEVICE);
page = page_alloc[i].page;
- atomic_set(&page->_count, 1);
+ set_page_count(page, 1);
put_page(page);
}
}
@@ -165,7 +164,7 @@
en_dbg(DRV, priv, " frag %d allocator: - size:%d frags:%d\n",
i, ring->page_alloc[i].page_size,
- atomic_read(&ring->page_alloc[i].page->_count));
+ page_ref_count(ring->page_alloc[i].page));
}
return 0;
@@ -177,7 +176,7 @@
dma_unmap_page(priv->ddev, page_alloc->dma,
page_alloc->page_size, PCI_DMA_FROMDEVICE);
page = page_alloc->page;
- atomic_set(&page->_count, 1);
+ set_page_count(page, 1);
put_page(page);
page_alloc->page = NULL;
}
diff --git a/drivers/net/ethernet/sun/niu.c b/drivers/net/ethernet/sun/niu.c
index ab6051a..9cc4564 100644
--- a/drivers/net/ethernet/sun/niu.c
+++ b/drivers/net/ethernet/sun/niu.c
@@ -3341,7 +3341,7 @@
niu_hash_page(rp, page, addr);
if (rp->rbr_blocks_per_page > 1)
- atomic_add(rp->rbr_blocks_per_page - 1, &page->_count);
+ page_ref_add(page, rp->rbr_blocks_per_page - 1);
for (i = 0; i < rp->rbr_blocks_per_page; i++) {
__le32 *rbr = &rp->rbr[start_index + i];