mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd
__GFP_WAIT has been used to identify atomic context in callers that hold
spinlocks or are in interrupts. They are expected to be high priority and
have access one of two watermarks lower than "min" which can be referred
to as the "atomic reserve". __GFP_HIGH users get access to the first
lower watermark and can be called the "high priority reserve".
Over time, callers had a requirement to not block when fallback options
were available. Some have abused __GFP_WAIT leading to a situation where
an optimisitic allocation with a fallback option can access atomic
reserves.
This patch uses __GFP_ATOMIC to identify callers that are truely atomic,
cannot sleep and have no alternative. High priority users continue to use
__GFP_HIGH. __GFP_DIRECT_RECLAIM identifies callers that can sleep and
are willing to enter direct reclaim. __GFP_KSWAPD_RECLAIM to identify
callers that want to wake kswapd for background reclaim. __GFP_WAIT is
redefined as a caller that is willing to enter direct reclaim and wake
kswapd for background reclaim.
This patch then converts a number of sites
o __GFP_ATOMIC is used by callers that are high priority and have memory
pools for those requests. GFP_ATOMIC uses this flag.
o Callers that have a limited mempool to guarantee forward progress clear
__GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall
into this category where kswapd will still be woken but atomic reserves
are not used as there is a one-entry mempool to guarantee progress.
o Callers that are checking if they are non-blocking should use the
helper gfpflags_allow_blocking() where possible. This is because
checking for __GFP_WAIT as was done historically now can trigger false
positives. Some exceptions like dm-crypt.c exist where the code intent
is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to
flag manipulations.
o Callers that built their own GFP flags instead of starting with GFP_KERNEL
and friends now also need to specify __GFP_KSWAPD_RECLAIM.
The first key hazard to watch out for is callers that removed __GFP_WAIT
and was depending on access to atomic reserves for inconspicuous reasons.
In some cases it may be appropriate for them to use __GFP_HIGH.
The second key hazard is callers that assembled their own combination of
GFP flags instead of starting with something like GFP_KERNEL. They may
now wish to specify __GFP_KSWAPD_RECLAIM. It's almost certainly harmless
if it's missed in most cases as other activity will wake kswapd.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index c097909..b4b5680 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -357,7 +357,8 @@
}
if (has_payload && data_size) {
- page = drbd_alloc_pages(peer_device, nr_pages, (gfp_mask & __GFP_WAIT));
+ page = drbd_alloc_pages(peer_device, nr_pages,
+ gfpflags_allow_blocking(gfp_mask));
if (!page)
goto fail;
}
diff --git a/drivers/block/osdblk.c b/drivers/block/osdblk.c
index e229425..1b709a4 100644
--- a/drivers/block/osdblk.c
+++ b/drivers/block/osdblk.c
@@ -271,7 +271,7 @@
goto err_out;
tmp->bi_bdev = NULL;
- gfpmask &= ~__GFP_WAIT;
+ gfpmask &= ~__GFP_DIRECT_RECLAIM;
tmp->bi_next = NULL;
if (!new_chain)
diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c
index 30f5228..d7373ca 100644
--- a/drivers/connector/connector.c
+++ b/drivers/connector/connector.c
@@ -124,7 +124,8 @@
if (group)
return netlink_broadcast(dev->nls, skb, portid, group,
gfp_mask);
- return netlink_unicast(dev->nls, skb, portid, !(gfp_mask&__GFP_WAIT));
+ return netlink_unicast(dev->nls, skb, portid,
+ !gfpflags_allow_blocking(gfp_mask));
}
EXPORT_SYMBOL_GPL(cn_netlink_send_mult);
diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c
index 2a3973a..36a7c2d 100644
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -486,7 +486,7 @@
static int add_client_resource(struct client *client,
struct client_resource *resource, gfp_t gfp_mask)
{
- bool preload = !!(gfp_mask & __GFP_WAIT);
+ bool preload = gfpflags_allow_blocking(gfp_mask);
unsigned long flags;
int ret;
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 4d631a9..d58cb9e 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2215,7 +2215,7 @@
*/
mapping = file_inode(obj->base.filp)->i_mapping;
gfp = mapping_gfp_mask(mapping);
- gfp |= __GFP_NORETRY | __GFP_NOWARN | __GFP_NO_KSWAPD;
+ gfp |= __GFP_NORETRY | __GFP_NOWARN;
gfp &= ~(__GFP_IO | __GFP_WAIT);
sg = st->sgl;
st->nents = 0;
diff --git a/drivers/infiniband/core/sa_query.c b/drivers/infiniband/core/sa_query.c
index 8c014b3..59ab264 100644
--- a/drivers/infiniband/core/sa_query.c
+++ b/drivers/infiniband/core/sa_query.c
@@ -1083,7 +1083,7 @@
static int send_mad(struct ib_sa_query *query, int timeout_ms, gfp_t gfp_mask)
{
- bool preload = !!(gfp_mask & __GFP_WAIT);
+ bool preload = gfpflags_allow_blocking(gfp_mask);
unsigned long flags;
int ret, id;
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 0d533bb..8b2be1e 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -2668,7 +2668,7 @@
page = alloc_pages(flag | __GFP_NOWARN, get_order(size));
if (!page) {
- if (!(flag & __GFP_WAIT))
+ if (!gfpflags_allow_blocking(flag))
return NULL;
page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 7cf80c1..f1042da 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3647,7 +3647,7 @@
flags |= GFP_DMA32;
}
- if (flags & __GFP_WAIT) {
+ if (gfpflags_allow_blocking(flags)) {
unsigned int count = size >> PAGE_SHIFT;
page = dma_alloc_from_contiguous(dev, count, order);
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 3729b39..917d47e 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -994,7 +994,7 @@
struct bio_vec *bvec;
retry:
- if (unlikely(gfp_mask & __GFP_WAIT))
+ if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM))
mutex_lock(&cc->bio_alloc_lock);
clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
@@ -1010,7 +1010,7 @@
if (!page) {
crypt_free_buffer_pages(cc, clone);
bio_put(clone);
- gfp_mask |= __GFP_WAIT;
+ gfp_mask |= __GFP_DIRECT_RECLAIM;
goto retry;
}
@@ -1027,7 +1027,7 @@
}
return_clone:
- if (unlikely(gfp_mask & __GFP_WAIT))
+ if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM))
mutex_unlock(&cc->bio_alloc_lock);
return clone;
diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c
index 3a7cade..1452ed9 100644
--- a/drivers/md/dm-kcopyd.c
+++ b/drivers/md/dm-kcopyd.c
@@ -244,7 +244,7 @@
*pages = NULL;
do {
- pl = alloc_pl(__GFP_NOWARN | __GFP_NORETRY);
+ pl = alloc_pl(__GFP_NOWARN | __GFP_NORETRY | __GFP_KSWAPD_RECLAIM);
if (unlikely(!pl)) {
/* Use reserved pages */
pl = kc->pages;
diff --git a/drivers/media/pci/solo6x10/solo6x10-v4l2-enc.c b/drivers/media/pci/solo6x10/solo6x10-v4l2-enc.c
index 1bd2fd4..4432fd6 100644
--- a/drivers/media/pci/solo6x10/solo6x10-v4l2-enc.c
+++ b/drivers/media/pci/solo6x10/solo6x10-v4l2-enc.c
@@ -1297,7 +1297,7 @@
solo_enc->vidq.ops = &solo_enc_video_qops;
solo_enc->vidq.mem_ops = &vb2_dma_sg_memops;
solo_enc->vidq.drv_priv = solo_enc;
- solo_enc->vidq.gfp_flags = __GFP_DMA32;
+ solo_enc->vidq.gfp_flags = __GFP_DMA32 | __GFP_KSWAPD_RECLAIM;
solo_enc->vidq.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
solo_enc->vidq.buf_struct_size = sizeof(struct solo_vb2_buf);
solo_enc->vidq.lock = &solo_enc->lock;
diff --git a/drivers/media/pci/solo6x10/solo6x10-v4l2.c b/drivers/media/pci/solo6x10/solo6x10-v4l2.c
index 26df903..f7ce493 100644
--- a/drivers/media/pci/solo6x10/solo6x10-v4l2.c
+++ b/drivers/media/pci/solo6x10/solo6x10-v4l2.c
@@ -678,7 +678,7 @@
solo_dev->vidq.mem_ops = &vb2_dma_contig_memops;
solo_dev->vidq.drv_priv = solo_dev;
solo_dev->vidq.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
- solo_dev->vidq.gfp_flags = __GFP_DMA32;
+ solo_dev->vidq.gfp_flags = __GFP_DMA32 | __GFP_KSWAPD_RECLAIM;
solo_dev->vidq.buf_struct_size = sizeof(struct solo_vb2_buf);
solo_dev->vidq.lock = &solo_dev->lock;
ret = vb2_queue_init(&solo_dev->vidq);
diff --git a/drivers/media/pci/tw68/tw68-video.c b/drivers/media/pci/tw68/tw68-video.c
index 4c3293d..46642ef 100644
--- a/drivers/media/pci/tw68/tw68-video.c
+++ b/drivers/media/pci/tw68/tw68-video.c
@@ -979,7 +979,7 @@
dev->vidq.ops = &tw68_video_qops;
dev->vidq.mem_ops = &vb2_dma_sg_memops;
dev->vidq.drv_priv = dev;
- dev->vidq.gfp_flags = __GFP_DMA32;
+ dev->vidq.gfp_flags = __GFP_DMA32 | __GFP_KSWAPD_RECLAIM;
dev->vidq.buf_struct_size = sizeof(struct tw68_buf);
dev->vidq.lock = &dev->lock;
dev->vidq.min_buffers_needed = 2;
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 8bbbb75..2dfb291 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -1188,8 +1188,7 @@
*/
void *mtd_kmalloc_up_to(const struct mtd_info *mtd, size_t *size)
{
- gfp_t flags = __GFP_NOWARN | __GFP_WAIT |
- __GFP_NORETRY | __GFP_NO_KSWAPD;
+ gfp_t flags = __GFP_NOWARN | __GFP_DIRECT_RECLAIM | __GFP_NORETRY;
size_t min_alloc = max_t(size_t, mtd->writesize, PAGE_SIZE);
void *kbuf;
diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index 44173be..f8d7a2f 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
@@ -691,7 +691,7 @@
{
if (fp->rx_frag_size) {
/* GFP_KERNEL allocations are used only during initialization */
- if (unlikely(gfp_mask & __GFP_WAIT))
+ if (unlikely(gfpflags_allow_blocking(gfp_mask)))
return (void *)__get_free_page(gfp_mask);
return netdev_alloc_frag(fp->rx_frag_size);
diff --git a/drivers/staging/android/ion/ion_system_heap.c b/drivers/staging/android/ion/ion_system_heap.c
index ada724a..d4c3e55 100644
--- a/drivers/staging/android/ion/ion_system_heap.c
+++ b/drivers/staging/android/ion/ion_system_heap.c
@@ -27,7 +27,7 @@
#include "ion_priv.h"
static gfp_t high_order_gfp_flags = (GFP_HIGHUSER | __GFP_ZERO | __GFP_NOWARN |
- __GFP_NORETRY) & ~__GFP_WAIT;
+ __GFP_NORETRY) & ~__GFP_DIRECT_RECLAIM;
static gfp_t low_order_gfp_flags = (GFP_HIGHUSER | __GFP_ZERO | __GFP_NOWARN);
static const unsigned int orders[] = {8, 4, 0};
static const int num_orders = ARRAY_SIZE(orders);
diff --git a/drivers/staging/lustre/include/linux/libcfs/libcfs_private.h b/drivers/staging/lustre/include/linux/libcfs/libcfs_private.h
index 6af733d..f0b0423 100644
--- a/drivers/staging/lustre/include/linux/libcfs/libcfs_private.h
+++ b/drivers/staging/lustre/include/linux/libcfs/libcfs_private.h
@@ -95,7 +95,7 @@
do { \
LASSERT(!in_interrupt() || \
((size) <= LIBCFS_VMALLOC_SIZE && \
- ((mask) & __GFP_WAIT) == 0)); \
+ !gfpflags_allow_blocking(mask))); \
} while (0)
#define LIBCFS_ALLOC_POST(ptr, size) \
diff --git a/drivers/usb/host/u132-hcd.c b/drivers/usb/host/u132-hcd.c
index 0a94895..692ccc6 100644
--- a/drivers/usb/host/u132-hcd.c
+++ b/drivers/usb/host/u132-hcd.c
@@ -2244,7 +2244,7 @@
{
struct u132 *u132 = hcd_to_u132(hcd);
if (irqs_disabled()) {
- if (__GFP_WAIT & mem_flags) {
+ if (gfpflags_allow_blocking(mem_flags)) {
printk(KERN_ERR "invalid context for function that might sleep\n");
return -EINVAL;
}
diff --git a/drivers/video/fbdev/vermilion/vermilion.c b/drivers/video/fbdev/vermilion/vermilion.c
index 6b70d7f..1c1e95a 100644
--- a/drivers/video/fbdev/vermilion/vermilion.c
+++ b/drivers/video/fbdev/vermilion/vermilion.c
@@ -99,7 +99,7 @@
* below the first 16MB.
*/
- flags = __GFP_DMA | __GFP_HIGH;
+ flags = __GFP_DMA | __GFP_HIGH | __GFP_KSWAPD_RECLAIM;
va->logical =
__get_free_pages(flags, --max_order);
} while (va->logical == 0 && max_order > min_order);