From 581bf81d34ee312fce1fe4d28b6d1f03995b350c Mon Sep 17 00:00:00 2001 From: Willy Tarreau Date: Mon, 25 Jan 2016 02:19:13 +0100 Subject: [PATCH] MEDIUM: pools: add a new flag to avoid rounding pool size up Usually it's desirable to merge similarly sized pools, which is the reason why their size is rounded up to the next multiple of 16. But for the buffers this is problematic because we add the size of struct buffer to the user-requested size, and the rounding results in 8 extra bytes that are usable in the end. So the user gets more bytes than asked for, and in case of SSL it results in short writes for the extra bytes that are sent above multiples of 16 kB. So we add a new flag MEM_F_EXACT to request that the size is not rounded up when creating the entry. Thus it doesn't disable merging. --- include/common/memory.h | 1 + src/memory.c | 10 +++++++--- 2 files changed, 8 insertions(+), 3 deletions(-) diff --git a/include/common/memory.h b/include/common/memory.h index 2b7121b42..d52fb6265 100644 --- a/include/common/memory.h +++ b/include/common/memory.h @@ -33,6 +33,7 @@ #else #define MEM_F_SHARED 0 #endif +#define MEM_F_EXACT 0x2 /* reserve an extra void* at the end of a pool for linking */ #ifdef DEBUG_MEMORY_POOLS diff --git a/src/memory.c b/src/memory.c index 036f78607..53ab4890a 100644 --- a/src/memory.c +++ b/src/memory.c @@ -24,7 +24,9 @@ int mem_poison_byte = -1; /* Try to find an existing shared pool with the same characteristics and * returns it, otherwise creates this one. NULL is returned if no memory - * is available for a new creation. + * is available for a new creation. Two flags are supported : + * - MEM_F_SHARED to indicate that the pool may be shared with other users + * - MEM_F_EXACT to indicate that the size must not be rounded up */ struct pool_head *create_pool(char *name, unsigned int size, unsigned int flags) { @@ -41,8 +43,10 @@ struct pool_head *create_pool(char *name, unsigned int size, unsigned int flags) * so that the visible parts outside are not affected. */ - align = 16; - size = ((size + POOL_EXTRA + align - 1) & -align) - POOL_EXTRA; + if (!(flags & MEM_F_EXACT)) { + align = 16; + size = ((size + POOL_EXTRA + align - 1) & -align) - POOL_EXTRA; + } start = &pools; pool = NULL;