Re: [LTP] [PATCH] increasing buffer size for correct alignment

[Han Pingtian <hanpt@linux.vnet.ibm.com>]

On Mon, Jan 26, 2015 at 02:45:56PM +0100, Cyril Hrubis wrote:
> You are adding the page_size_mask to all uses of total_ram, wouldn't it
> be easier to add it to the total_ram at the start of the function (and
> remove the page_size_mask from the malloc() call that has it allready)?
> 
Yes, you're right. This is the new patch. Please review. Thanks.


From 8d0521c7fbee1b46f27d8268fee28e9721c79cc2 Mon Sep 17 00:00:00 2001
From: Han Pingtian <hanpt@linux.vnet.ibm.com>
Date: Mon, 26 Jan 2015 17:29:41 +0800
Subject: [PATCH] increasing buffer size for correct alignment

For align buffer address to the number specified by -a option in
aio-stress, it needs to add page_size_mask extra length to total_ram
before call allocation functions. Or it wouldn't be correct in this line
after the allocation:

         p = (char *)((intptr_t) (p + page_size_mask) & ~page_size_mask);

Signed-off-by: Han Pingtian <hanpt@linux.vnet.ibm.com>
---
 testcases/kernel/io/ltp-aiodio/aio-stress.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/testcases/kernel/io/ltp-aiodio/aio-stress.c b/testcases/kernel/io/ltp-aiodio/aio-stress.c
index 0b7148c..06a4953 100644
--- a/testcases/kernel/io/ltp-aiodio/aio-stress.c
+++ b/testcases/kernel/io/ltp-aiodio/aio-stress.c
@@ -1019,8 +1019,11 @@ int setup_shared_mem(int num_threads, int num_files, int depth,
 	if (verify)
 		total_ram += padded_reclen;
 
+	/* for aligning buffer after the allocation */
+	total_ram += page_size_mask;
+
 	if (use_shm == USE_MALLOC) {
-		p = malloc(total_ram + page_size_mask);
+		p = malloc(total_ram);
 	} else if (use_shm == USE_SHM) {
 		shm_id = shmget(IPC_PRIVATE, total_ram, IPC_CREAT | 0700);
 		if (shm_id < 0) {
-- 
1.9.3


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