diff mbox series

[net-next] tcp: shrink inet_connection_sock icsk_mtup enabled and probe_size

Message ID 20210129185438.1813237-1-ncardwell.kernel@gmail.com (mailing list archive)
State Accepted
Commit 14e8e0f6008865d823a8184a276702a6c3cbef3d
Delegated to: Netdev Maintainers
Headers show
Series [net-next] tcp: shrink inet_connection_sock icsk_mtup enabled and probe_size | expand

Checks

Context Check Description
netdev/cover_letter success Link
netdev/fixes_present success Link
netdev/patch_count success Link
netdev/tree_selection success Clearly marked for net-next
netdev/subject_prefix success Link
netdev/cc_maintainers warning 1 maintainers not CCed: kuba@kernel.org
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 3601 this patch: 3601
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Link
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 17 lines checked
netdev/build_allmodconfig_warn success Errors and warnings before: 4025 this patch: 4025
netdev/header_inline success Link
netdev/stable success Stable not CCed

Commit Message

Neal Cardwell Jan. 29, 2021, 6:54 p.m. UTC 
From: Neal Cardwell <ncardwell@google.com>

This commit shrinks inet_connection_sock by 4 bytes, by shrinking
icsk_mtup.enabled from 32 bits to 1 bit, and shrinking
icsk_mtup.probe_size from s32 to an unsuigned 31 bit field.

This is to save space to compensate for the recent introduction of a
new u32 in inet_connection_sock, icsk_probes_tstamp, in the recent bug
fix commit 9d9b1ee0b2d1 ("tcp: fix TCP_USER_TIMEOUT with zero window").

This should not change functionality, since icsk_mtup.enabled is only
ever set to 0 or 1, and icsk_mtup.probe_size can only be either 0
or a positive MTU value returned by tcp_mss_to_mtu()

Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/inet_connection_sock.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org Jan. 30, 2021, 7:40 a.m. UTC | #1 
Hello:

This patch was applied to netdev/net-next.git (refs/heads/master):

On Fri, 29 Jan 2021 13:54:38 -0500 you wrote:
> From: Neal Cardwell <ncardwell@google.com>
> 
> This commit shrinks inet_connection_sock by 4 bytes, by shrinking
> icsk_mtup.enabled from 32 bits to 1 bit, and shrinking
> icsk_mtup.probe_size from s32 to an unsuigned 31 bit field.
> 
> This is to save space to compensate for the recent introduction of a
> new u32 in inet_connection_sock, icsk_probes_tstamp, in the recent bug
> fix commit 9d9b1ee0b2d1 ("tcp: fix TCP_USER_TIMEOUT with zero window").
> 
> [...]

Here is the summary with links:
  - [net-next] tcp: shrink inet_connection_sock icsk_mtup enabled and probe_size
    https://git.kernel.org/netdev/net-next/c/14e8e0f60088

You are awesome, thank you!
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diff mbox series

Patch

diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index c11f80f328f1..10a625760de9 100644
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -120,14 +120,14 @@  struct inet_connection_sock {
 		__u16		  rcv_mss;	 /* MSS used for delayed ACK decisions	   */
 	} icsk_ack;
 	struct {
-		int		  enabled;
-
 		/* Range of MTUs to search */
 		int		  search_high;
 		int		  search_low;
 
 		/* Information on the current probe. */
-		int		  probe_size;
+		u32		  probe_size:31,
+		/* Is the MTUP feature enabled for this connection? */
+				  enabled:1;
 
 		u32		  probe_timestamp;
 	} icsk_mtup;