From: Stefano Brivio <sbrivio@redhat.com>
To: passt-dev@passt.top
Cc: Laurent Vivier <lvivier@redhat.com>,
David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCH v3 04/20] flow, flow_table: Pad flow table entries to 128 bytes, hash entries to 32 bits
Date: Fri, 31 Jan 2025 20:39:37 +0100 [thread overview]
Message-ID: <20250131193953.3034031-5-sbrivio@redhat.com> (raw)
In-Reply-To: <20250131193953.3034031-1-sbrivio@redhat.com>
...to keep migration sane. Right now, the biggest struct in union flow
is struct tcp_splice_conn with 120 bytes on x86_64, which should also
have the biggest storage and alignment requirements of any
architecture we might run on.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
---
flow.h | 18 ++++++++++++------
flow_table.h | 13 ++++++++++---
2 files changed, 22 insertions(+), 9 deletions(-)
diff --git a/flow.h b/flow.h
index 24ba3ef..8eb5964 100644
--- a/flow.h
+++ b/flow.h
@@ -202,15 +202,21 @@ struct flow_common {
/**
* struct flow_sidx - ID for one side of a specific flow
- * @sidei: Index of side referenced (0 or 1)
- * @flowi: Index of flow referenced
+ * @sidei: Index of side referenced (0 or 1)
+ * @flowi: Index of flow referenced
+ * @flow_sidx_storage: Pad to 32 bits
*/
typedef struct flow_sidx {
- unsigned sidei :1;
- unsigned flowi :FLOW_INDEX_BITS;
+ union {
+ struct {
+ unsigned sidei :1;
+ unsigned flowi :FLOW_INDEX_BITS;
+ };
+ uint32_t flow_sidx_storage;
+ };
} flow_sidx_t;
-static_assert(sizeof(flow_sidx_t) <= sizeof(uint32_t),
- "flow_sidx_t must fit within 32 bits");
+static_assert(sizeof(flow_sidx_t) == sizeof(uint32_t),
+ "flow_sidx_t must be 32-bit wide");
#define FLOW_SIDX_NONE ((flow_sidx_t){ .flowi = FLOW_MAX })
diff --git a/flow_table.h b/flow_table.h
index f15db53..007f4dd 100644
--- a/flow_table.h
+++ b/flow_table.h
@@ -26,9 +26,13 @@ struct flow_free_cluster {
/**
* union flow - Descriptor for a logical packet flow (e.g. connection)
- * @f: Fields common between all variants
- * @tcp: Fields for non-spliced TCP connections
- * @tcp_splice: Fields for spliced TCP connections
+ * @f: Fields common between all variants
+ * @free: Entry in a cluster of free entries
+ * @tcp: Fields for non-spliced TCP connections
+ * @tcp_splice: Fields for spliced TCP connections
+ * @ping: Tracking for ping flows
+ * @udp: Tracking for UDP flows
+ * @flow_storage: Pad flow entries to 128 bytes to ease state migration
*/
union flow {
struct flow_common f;
@@ -37,8 +41,11 @@ union flow {
struct tcp_splice_conn tcp_splice;
struct icmp_ping_flow ping;
struct udp_flow udp;
+ char flow_storage[128];
};
+static_assert(sizeof(union flow) == 128, "union flow should be 128-byte wide");
+
/* Global Flow Table */
extern unsigned flow_first_free;
extern union flow flowtab[];
--
@@ -26,9 +26,13 @@ struct flow_free_cluster {
/**
* union flow - Descriptor for a logical packet flow (e.g. connection)
- * @f: Fields common between all variants
- * @tcp: Fields for non-spliced TCP connections
- * @tcp_splice: Fields for spliced TCP connections
+ * @f: Fields common between all variants
+ * @free: Entry in a cluster of free entries
+ * @tcp: Fields for non-spliced TCP connections
+ * @tcp_splice: Fields for spliced TCP connections
+ * @ping: Tracking for ping flows
+ * @udp: Tracking for UDP flows
+ * @flow_storage: Pad flow entries to 128 bytes to ease state migration
*/
union flow {
struct flow_common f;
@@ -37,8 +41,11 @@ union flow {
struct tcp_splice_conn tcp_splice;
struct icmp_ping_flow ping;
struct udp_flow udp;
+ char flow_storage[128];
};
+static_assert(sizeof(union flow) == 128, "union flow should be 128-byte wide");
+
/* Global Flow Table */
extern unsigned flow_first_free;
extern union flow flowtab[];
--
2.43.0
next prev parent reply other threads:[~2025-01-31 19:39 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-31 19:39 [PATCH v3 00/20] Draft, incomplete series introducing state migration Stefano Brivio
2025-01-31 19:39 ` [PATCH v3 01/20] tcp: Always pass NULL event with EPOLL_CTL_DEL Stefano Brivio
2025-01-31 19:39 ` [PATCH v3 02/20] util: Rename and make global vu_remove_watch() Stefano Brivio
2025-01-31 19:39 ` [PATCH v3 03/20] icmp, udp: Pad time_t timestamp to 64-bit to ease state migration Stefano Brivio
2025-01-31 19:39 ` Stefano Brivio [this message]
2025-01-31 19:39 ` [PATCH v3 05/20] flow_table: Use size in extern declaration for flowtab Stefano Brivio
2025-01-31 19:39 ` [PATCH v3 06/20] util: Add read_remainder() and read_all_buf() Stefano Brivio
2025-01-31 19:39 ` [PATCH v3 07/20] Introduce facilities for guest migration on top of vhost-user infrastructure Stefano Brivio
2025-01-31 19:39 ` [PATCH v3 08/20] Introduce passt-repair Stefano Brivio
2025-02-03 1:46 ` David Gibson
2025-01-31 19:39 ` [PATCH v3 09/20] Add interfaces and configuration bits for passt-repair Stefano Brivio
2025-02-03 5:22 ` David Gibson
2025-01-31 19:39 ` [PATCH v3 10/20] flow, tcp: Basic pre-migration source handler to dump sequence numbers Stefano Brivio
2025-01-31 19:39 ` [PATCH v3 11/20] migrate: vu_migrate_{source,target}() aren't actually vu speciic Stefano Brivio
2025-01-31 19:39 ` [PATCH v3 12/20] migrate: Move repair_sock_init() to vu_init() Stefano Brivio
2025-01-31 19:39 ` [PATCH v3 13/20] migrate: Make more handling common rather than vhost-user specific Stefano Brivio
2025-01-31 19:39 ` [PATCH v3 14/20] migrate: Don't handle the migration channel through epoll Stefano Brivio
2025-02-03 1:50 ` David Gibson
2025-02-03 5:38 ` Stefano Brivio
2025-02-03 8:45 ` David Gibson
2025-02-03 2:16 ` David Gibson
2025-01-31 19:39 ` [PATCH v3 15/20] flow, flow_table: Export declaration of hash table Stefano Brivio
2025-01-31 19:39 ` [PATCH v3 16/20] vhost_user: Turn vhost-user message reports to trace() Stefano Brivio
2025-02-03 3:11 ` David Gibson
2025-02-03 6:10 ` Stefano Brivio
2025-02-03 8:47 ` David Gibson
2025-01-31 19:39 ` [PATCH v3 17/20] vhost_user: Make source quit after reporting migration state Stefano Brivio
2025-02-03 1:55 ` David Gibson
2025-02-03 6:09 ` Stefano Brivio
2025-02-03 8:52 ` David Gibson
2025-02-03 9:44 ` Stefano Brivio
2025-01-31 19:39 ` [PATCH v3 18/20] tcp: Get our socket port using getsockname() when connecting from guest Stefano Brivio
2025-02-03 2:05 ` David Gibson
2025-02-03 6:09 ` Stefano Brivio
2025-02-03 8:59 ` David Gibson
2025-02-03 9:45 ` Stefano Brivio
2025-01-31 19:39 ` [PATCH v3 19/20] tcp: Add HOSTSIDE(x), HOSTFLOW(x) macros Stefano Brivio
2025-02-03 2:06 ` David Gibson
2025-01-31 19:39 ` [PATCH v3 20/20] Implement target side of migration Stefano Brivio
2025-02-01 7:45 ` [PATCH v3 00/20] Draft, incomplete series introducing state migration Stefano Brivio
2025-02-03 2:18 ` David Gibson
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