netdev - [PATCH net-next 1/7] Revert "net: set SK_MEM

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Message-Id: <20220609063412.2205738-2-eric.dumazet@gmail.com>
Date:   Wed,  8 Jun 2022 23:34:06 -0700
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>
Cc:     netdev <netdev@...r.kernel.org>,
        Soheil Hassas Yeganeh <soheil@...gle.com>,
        Wei Wang <weiwan@...gle.com>,
        Shakeel Butt <shakeelb@...gle.com>,
        Neal Cardwell <ncardwell@...gle.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Eric Dumazet <eric.dumazet@...il.com>
Subject: [PATCH net-next 1/7] Revert "net: set SK_MEM_QUANTUM to 4096"

From: Eric Dumazet <edumazet@...gle.com>

This reverts commit bd68a2a854ad5a85f0c8d0a9c8048ca3f6391efb.

This change broke memcg on arches with PAGE_SIZE != 4096

Later, commit 2bb2f5fb21b04 ("net: add new socket option SO_RESERVE_MEM")
also assumed PAGE_SIZE==SK_MEM_QUANTUM

Following patches in the series will greatly reduce the over allocations
problem.

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 include/net/sock.h | 16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index 657873e2d90fbb2254144aa2405a0551a789edbb..5c5265269899091a7bb8f14766085a463a476403 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1532,25 +1532,15 @@ int __sk_mem_schedule(struct sock *sk, int size, int kind);
 void __sk_mem_reduce_allocated(struct sock *sk, int amount);
 void __sk_mem_reclaim(struct sock *sk, int amount);
 
-/* We used to have PAGE_SIZE here, but systems with 64KB pages
- * do not necessarily have 16x time more memory than 4KB ones.
- */
-#define SK_MEM_QUANTUM 4096
+#define SK_MEM_QUANTUM ((int)PAGE_SIZE)
 #define SK_MEM_QUANTUM_SHIFT ilog2(SK_MEM_QUANTUM)
 #define SK_MEM_SEND	0
 #define SK_MEM_RECV	1
 
-/* sysctl_mem values are in pages, we convert them in SK_MEM_QUANTUM units */
+/* sysctl_mem values are in pages */
 static inline long sk_prot_mem_limits(const struct sock *sk, int index)
 {
-	long val = sk->sk_prot->sysctl_mem[index];
-
-#if PAGE_SIZE > SK_MEM_QUANTUM
-	val <<= PAGE_SHIFT - SK_MEM_QUANTUM_SHIFT;
-#elif PAGE_SIZE < SK_MEM_QUANTUM
-	val >>= SK_MEM_QUANTUM_SHIFT - PAGE_SHIFT;
-#endif
-	return val;
+	return sk->sk_prot->sysctl_mem[index];
 }
 
 static inline int sk_mem_pages(int amt)
-- 
2.36.1.255.ge46751e96f-goog