From: Arjun Shankar <arjun.is@lostca.se>
To: libc-stable@sourceware.org
Subject: [2.30 COMMITTED] Base max_fast on alignment, not width, of bins (Bug 24903)
Date: Tue, 01 Jan 2019 00:00:00 -0000 [thread overview]
Message-ID: <20191119121536.GD89708@aloka.lostca.se> (raw)
set_max_fast sets the "impossibly small" value based on,
eventually, MALLOC_ALIGNMENT. The comparisons for the smallest
chunk used is, eventually, MIN_CHUNK_SIZE. Note that i386
is the only platform where these are the same, so a smallest
chunk *would* be put in a no-fastbins fastbin.
This change calculates the "impossibly small" value
based on MIN_CHUNK_SIZE instead, so that we can know it will
always be impossibly small.
(cherry picked from commit ff12e0fb91b9072800f031cb21fb2651ee7b6251)
---
malloc/malloc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/malloc/malloc.c b/malloc/malloc.c
index fe973770a6..8c68b21b2b 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -1621,7 +1621,7 @@ static INTERNAL_SIZE_T global_max_fast;
#define set_max_fast(s) \
global_max_fast = (((s) == 0) \
- ? SMALLBIN_WIDTH : ((s + SIZE_SZ) & ~MALLOC_ALIGN_MASK))
+ ? MIN_CHUNK_SIZE / 2 : ((s + SIZE_SZ) & ~MALLOC_ALIGN_MASK))
static inline INTERNAL_SIZE_T
get_max_fast (void)
--
2.21.0
reply other threads:[~2019-11-19 12:15 UTC|newest]
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