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author | arybchik <arybchik@FreeBSD.org> | 2015-03-25 10:59:24 +0000 |
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committer | arybchik <arybchik@FreeBSD.org> | 2015-03-25 10:59:24 +0000 |
commit | db246d0ceeaaebb15869a8e06f8b2f4b2d7306f6 (patch) | |
tree | 9eba9d99135baa4462163778652bac35cc28bc0a | |
parent | 4f836db713790f3820d88bca7dbf84eeb70d17fc (diff) | |
download | FreeBSD-src-db246d0ceeaaebb15869a8e06f8b2f4b2d7306f6.zip FreeBSD-src-db246d0ceeaaebb15869a8e06f8b2f4b2d7306f6.tar.gz |
MFC: 279094
sfxge: more accurate calculation of maximum number of TSO segments
Sponsored by: Solarflare Communications, Inc.
Approved by: gnn (mentor)
-rw-r--r-- | sys/dev/sfxge/sfxge_tx.c | 6 | ||||
-rw-r--r-- | sys/dev/sfxge/sfxge_tx.h | 12 |
2 files changed, 14 insertions, 4 deletions
diff --git a/sys/dev/sfxge/sfxge_tx.c b/sys/dev/sfxge/sfxge_tx.c index c1e09a4..63dd8d7 100644 --- a/sys/dev/sfxge/sfxge_tx.c +++ b/sys/dev/sfxge/sfxge_tx.c @@ -72,10 +72,10 @@ __FBSDID("$FreeBSD$"); * maximum mbuf length we might need more than a ring-ful of * descriptors, but this should not happen in practice except * due to deliberate attack. In that case we will truncate - * the output at a packet boundary. Allow for a reasonable - * minimum MSS of 512. + * the output at a packet boundary. */ -#define SFXGE_TSO_MAX_DESC ((65535 / 512) * 2 + SFXGE_TX_MAPPING_MAX_SEG - 1) +#define SFXGE_TSO_MAX_DESC \ + (SFXGE_TSO_MAX_SEGS * 2 + SFXGE_TX_MAPPING_MAX_SEG - 1) #define SFXGE_TXQ_BLOCK_LEVEL(_entries) ((_entries) - SFXGE_TSO_MAX_DESC) #ifdef SFXGE_HAVE_MQ diff --git a/sys/dev/sfxge/sfxge_tx.h b/sys/dev/sfxge/sfxge_tx.h index b430288..3965ffd 100644 --- a/sys/dev/sfxge/sfxge_tx.h +++ b/sys/dev/sfxge/sfxge_tx.h @@ -36,12 +36,22 @@ #include <netinet/ip.h> #include <netinet/tcp.h> +/* Maximum size of TSO packet */ +#define SFXGE_TSO_MAX_SIZE (65535) + +/* + * Maximum number of segments to be created for a TSO packet. + * Allow for a reasonable minimum MSS of 512. + */ +#define SFXGE_TSO_MAX_SEGS howmany(SFXGE_TSO_MAX_SIZE, 512) + /* Maximum number of DMA segments needed to map an mbuf chain. With * TSO, the mbuf length may be just over 64K, divided into 2K mbuf * clusters. (The chain could be longer than this initially, but can * be shortened with m_collapse().) */ -#define SFXGE_TX_MAPPING_MAX_SEG (64 / 2 + 1) +#define SFXGE_TX_MAPPING_MAX_SEG \ + (1 + howmany(SFXGE_TSO_MAX_SIZE, MCLBYTES)) /* * Buffer mapping flags. |