[PATCH v4 3/6] mm: Allow GFP_ACCOUNT to be used in alloc_pages_nolock().

[Alexei Starovoitov <alexei.starovoitov@gmail.com>]

From: Alexei Starovoitov <ast@kernel.org>

Change alloc_pages_nolock() to default to __GFP_COMP when allocating
pages, since upcoming reentrant alloc_slab_page() needs __GFP_COMP.
Also allow __GFP_ACCOUNT flag to be specified,
since BPF infra needs __GFP_ACCOUNT.

Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 include/linux/gfp.h  |  2 +-
 kernel/bpf/syscall.c |  2 +-
 mm/page_alloc.c      | 10 ++++++----
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 5ebf26fcdcfa..0ceb4e09306c 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -354,7 +354,7 @@ static inline struct page *alloc_page_vma_noprof(gfp_t gfp,
 }
 #define alloc_page_vma(...)			alloc_hooks(alloc_page_vma_noprof(__VA_ARGS__))
 
-struct page *alloc_pages_nolock_noprof(int nid, unsigned int order);
+struct page *alloc_pages_nolock_noprof(gfp_t gfp_flags, int nid, unsigned int order);
 #define alloc_pages_nolock(...)			alloc_hooks(alloc_pages_nolock_noprof(__VA_ARGS__))
 
 extern unsigned long get_free_pages_noprof(gfp_t gfp_mask, unsigned int order);
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index dd5304c6ac3c..eb9b6c4c10e9 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -579,7 +579,7 @@ static bool can_alloc_pages(void)
 static struct page *__bpf_alloc_page(int nid)
 {
 	if (!can_alloc_pages())
-		return alloc_pages_nolock(nid, 0);
+		return alloc_pages_nolock(__GFP_ACCOUNT, nid, 0);
 
 	return alloc_pages_node(nid,
 				GFP_KERNEL | __GFP_ZERO | __GFP_ACCOUNT
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 78ddf1d43c6c..148945f0b667 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -7506,6 +7506,7 @@ static bool __free_unaccepted(struct page *page)
 
 /**
  * alloc_pages_nolock - opportunistic reentrant allocation from any context
+ * @gfp_flags: GFP flags. Only __GFP_ACCOUNT allowed.
  * @nid: node to allocate from
  * @order: allocation order size
  *
@@ -7519,7 +7520,7 @@ static bool __free_unaccepted(struct page *page)
  * Return: allocated page or NULL on failure. NULL does not mean EBUSY or EAGAIN.
  * It means ENOMEM. There is no reason to call it again and expect !NULL.
  */
-struct page *alloc_pages_nolock_noprof(int nid, unsigned int order)
+struct page *alloc_pages_nolock_noprof(gfp_t gfp_flags, int nid, unsigned int order)
 {
 	/*
 	 * Do not specify __GFP_DIRECT_RECLAIM, since direct claim is not allowed.
@@ -7541,12 +7542,13 @@ struct page *alloc_pages_nolock_noprof(int nid, unsigned int order)
 	 * specify it here to highlight that alloc_pages_nolock()
 	 * doesn't want to deplete reserves.
 	 */
-	gfp_t alloc_gfp = __GFP_NOWARN | __GFP_ZERO | __GFP_NOMEMALLOC
-			| __GFP_ACCOUNT;
+	gfp_t alloc_gfp = __GFP_NOWARN | __GFP_ZERO | __GFP_NOMEMALLOC | __GFP_COMP
+			| gfp_flags;
 	unsigned int alloc_flags = ALLOC_TRYLOCK;
 	struct alloc_context ac = { };
 	struct page *page;
 
+	VM_WARN_ON_ONCE(gfp_flags & ~__GFP_ACCOUNT);
 	/*
 	 * In PREEMPT_RT spin_trylock() will call raw_spin_lock() which is
 	 * unsafe in NMI. If spin_trylock() is called from hard IRQ the current
@@ -7584,7 +7586,7 @@ struct page *alloc_pages_nolock_noprof(int nid, unsigned int order)
 	if (page)
 		set_page_refcounted(page);
 
-	if (memcg_kmem_online() && page &&
+	if (memcg_kmem_online() && page && (gfp_flags & __GFP_ACCOUNT) &&
 	    unlikely(__memcg_kmem_charge_page(page, alloc_gfp, order) != 0)) {
 		free_pages_nolock(page, order);
 		page = NULL;
-- 
2.47.1