Currently there seems to be three page frag implementions
which all try to allocate order 3 page, if that fails, it
then fail back to allocate order 0 page, and each of them
all allow order 3 page allocation to fail under certain
condition by using specific gfp bits.
The gfp bits for order 3 page allocation are different
between different implementation, __GFP_NOMEMALLOC is
or'd to forbid access to emergency reserves memory for
__page_frag_cache_refill(), but it is not or'd in other
implementions, __GFP_DIRECT_RECLAIM is xor'd to avoid
direct reclaim in skb_page_frag_refill(), but it is not
xor'd in __page_frag_cache_refill().
This patch unifies the gfp bits used between different
implementions by or'ing __GFP_NOMEMALLOC and xor'ing
__GFP_DIRECT_RECLAIM for order 3 page allocation to avoid
possible pressure for mm.
Signed-off-by: Yunsheng Lin <linyunsheng@xxxxxxxxxx>
CC: Alexander Duyck <alexander.duyck@xxxxxxxxx>
---
drivers/vhost/net.c | 2 +-
mm/page_alloc.c | 4 ++--
net/core/sock.c | 2 +-
3 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index f2ed7167c848..e574e21cc0ca 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -670,7 +670,7 @@ static bool vhost_net_page_frag_refill(struct vhost_net *net, unsigned int sz,
/* Avoid direct reclaim but allow kswapd to wake */
pfrag->page = alloc_pages((gfp & ~__GFP_DIRECT_RECLAIM) |
__GFP_COMP | __GFP_NOWARN |
- __GFP_NORETRY,
+ __GFP_NORETRY | __GFP_NOMEMALLOC,
SKB_FRAG_PAGE_ORDER);
if (likely(pfrag->page)) {
pfrag->size = PAGE_SIZE << SKB_FRAG_PAGE_ORDER;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 9a16305cf985..1f0b36dd81b5 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4693,8 +4693,8 @@ static struct page *__page_frag_cache_refill(struct page_frag_cache *nc,
gfp_t gfp = gfp_mask;
#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
- gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY |
- __GFP_NOMEMALLOC;
+ gfp_mask = (gfp_mask & ~__GFP_DIRECT_RECLAIM) | __GFP_COMP |
+ __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC;
page = alloc_pages_node(NUMA_NO_NODE, gfp_mask,
PAGE_FRAG_CACHE_MAX_ORDER);
nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE;
diff --git a/net/core/sock.c b/net/core/sock.c
index fef349dd72fa..4efa9cae4b0d 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2904,7 +2904,7 @@ bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t gfp)
/* Avoid direct reclaim but allow kswapd to wake */
pfrag->page = alloc_pages((gfp & ~__GFP_DIRECT_RECLAIM) |
__GFP_COMP | __GFP_NOWARN |
- __GFP_NORETRY,
+ __GFP_NORETRY | __GFP_NOMEMALLOC,
SKB_FRAG_PAGE_ORDER);
if (likely(pfrag->page)) {
pfrag->size = PAGE_SIZE << SKB_FRAG_PAGE_ORDER;
--
2.33.0
