From 35ecd40c0d7e4f772d00dfec9f7077315ba5ca82 Mon Sep 17 00:00:00 2001 From: Dominique Martinet Date: Thu, 29 Oct 2026 06:00:12 +0000 Subject: [PATCH] 9p: optimize p9_fcall struct p9_fcall has a 1 byte hole followed by more data and then a single byte element: struct p9_fcall { u32 size; /* 0 4 */ u8 id; /* 4 1 */ /* XXX 1 byte hole, try to pack */ u16 tag; /* 6 2 */ size_t offset; /* 8 8 */ size_t capacity; /* 16 8 */ struct kmem_cache * cache; /* 24 8 */ u8 * sdata; /* 32 8 */ bool zc; /* 40 1 */ /* size: 48, cachelines: 1, members: 8 */ /* sum members: 40, holes: 1, sum holes: 1 */ /* padding: 7 */ /* last cacheline: 48 bytes */ }; move `zc` up to optimize it: struct p9_fcall { u32 size; /* 0 4 */ u8 id; /* 4 1 */ bool zc; /* 5 1 */ u16 tag; /* 6 2 */ size_t offset; /* 8 8 */ size_t capacity; /* 16 8 */ struct kmem_cache * cache; /* 24 8 */ u8 * sdata; /* 32 8 */ /* size: 40, cachelines: 1, members: 8 */ /* last cacheline: 40 bytes */ }; This in turn also makes p9_req_t 16 bytes smaller (152 -> 136) as it contains two of these. Signed-off-by: Dominique Martinet Message-ID: <20261029060014.3-1-asmadeus@codewreck.org> --- include/net/9p/9p.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/net/9p/9p.h b/include/net/9p/9p.h index 22ab7486795d..067e8a3b38d0 100644 --- a/include/net/9p/9p.h +++ b/include/net/9p/9p.h @@ -581,6 +581,7 @@ struct p9_rstatfs { struct p9_fcall { u32 size; u8 id; + bool zc; u16 tag; size_t offset; @@ -588,7 +589,6 @@ struct p9_fcall { struct kmem_cache *cache; u8 *sdata; - bool zc; }; int p9_errstr2errno(char *errstr, int len);