Re: [LTP] [PATCH] [PATCH] [PATCH v5] Hugetlb: Migrating libhugetlbfs test truncate_reserve_wraparound.c

[Andrea Cervesato via ltp <ltp@lists.linux.it>]

Hi!

Here a deeper analysis on the patch:

> Changes in v5:
> - removed unused parameters from sigbus_handler call
> - Added check for after_mmap_rsvd == initial_rsvd + 1
> - Used TST_EXP_EQ_LU for comparsion

This should stay away from the commit message. And commit message should have
a meaningful explaination of the test or what was done by the patch.

> 
> Signed-off-by: Pavithra <pavrampu@linux.ibm.com>
> ---
>  runtest/hugetlb                               |   1 +
>  testcases/kernel/mem/.gitignore               |   1 +
>  .../kernel/mem/hugetlb/hugemmap/hugemmap35.c  | 125 ++++++++++++++++++
>  3 files changed, 127 insertions(+)
>  create mode 100644 testcases/kernel/mem/hugetlb/hugemmap/hugemmap35.c
> 
> diff --git a/runtest/hugetlb b/runtest/hugetlb
> index 0896d3c94..8ee0e6f82 100644
> --- a/runtest/hugetlb
> +++ b/runtest/hugetlb
> @@ -36,6 +36,7 @@ hugemmap30 hugemmap30
>  hugemmap31 hugemmap31
>  hugemmap32 hugemmap32
>  hugemmap34 hugemmap34
> +hugemmap35 hugemmap35
>  hugemmap05_1 hugemmap05 -m
>  hugemmap05_2 hugemmap05 -s
>  hugemmap05_3 hugemmap05 -s -m
> diff --git a/testcases/kernel/mem/.gitignore b/testcases/kernel/mem/.gitignore
> index b4455de51..0e59035df 100644
> --- a/testcases/kernel/mem/.gitignore
> +++ b/testcases/kernel/mem/.gitignore
> @@ -36,6 +36,7 @@
>  /hugetlb/hugemmap/hugemmap31
>  /hugetlb/hugemmap/hugemmap32
>  /hugetlb/hugemmap/hugemmap34
> +/hugetlb/hugemmap/hugemmap35
>  /hugetlb/hugeshmat/hugeshmat01
>  /hugetlb/hugeshmat/hugeshmat02
>  /hugetlb/hugeshmat/hugeshmat03
> diff --git a/testcases/kernel/mem/hugetlb/hugemmap/hugemmap35.c b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap35.c
> new file mode 100644
> index 000000000..dc678661e
> --- /dev/null
> +++ b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap35.c
> @@ -0,0 +1,125 @@
> +// SPDX-License-Identifier: LGPL-2.1-or-later
> +/*
> + * Copyright (C) 2005-2006 David Gibson & Adam Litke, IBM Corporation.
> + */
> +
> +/*\
> + * [Description]

This is deprecated. Pleae use /*\

> + *
> + * Origin: https://github.com/libhugetlbfs/libhugetlbfs/blob/master/tests/truncate_reserve_wraparound.c
> + *
> + * At one stage, improper handling of tests against i_size could mess
> + * up accounting of reserved hugepages on certain truncate
> + * operations.

Can we write the description a bit better? At the moment is a bit generic.

> + *
> + */
> +
> +#include <signal.h>
> +#include <setjmp.h>
> +#include "hugetlb.h"
> +
> +#define MNTPOINT "hugetlbfs/"
> +
> +static long hpage_size;
> +static int fd = -1;
> +
> +static sigjmp_buf sig_escape;
> +
> +static void sigbus_handler(int signum LTP_ATTRIBUTE_UNUSED)
> +{
> +	siglongjmp(sig_escape, 17);
> +}
> +
> +static void run_test(void)
> +{
> +
> +	static int sigbus_count;

Is it needed to be static? We just need `int sigbus_count = 0`.

> +	unsigned long initial_rsvd, after_map_rsvd, after_touch_rsvd;
> +	unsigned long after_trunc_rsvd, after_unmap_rsvd, after_sigbus_rsvd;
> +	volatile unsigned int *q;
> +	void *p;
> +
> +	sigbus_count = 0;

And this goes away.

> +
> +	initial_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD);
> +	tst_res(TINFO, "Reserve count before map: %lu", initial_rsvd);
> +
> +	p = SAFE_MMAP(NULL, hpage_size, PROT_READ|PROT_WRITE, MAP_SHARED,
> +			fd, 0);
> +	q = p;
> +
> +	after_map_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD);
> +
> +	TST_EXP_EQ_LU(initial_rsvd + 1, after_map_rsvd);
> +	if (!TST_PASS)
> +		goto windup;
> +
> +	*q = 0;
> +	after_touch_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD);
> +
> +	TST_EXP_EQ_LU(initial_rsvd, after_touch_rsvd);
> +	if (!TST_PASS)
> +		goto windup;
> +
> +	SAFE_FTRUNCATE(fd, 0);
> +	after_trunc_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD);
> +
> +	TST_EXP_EQ_LU(initial_rsvd, after_trunc_rsvd);
> +	if (!TST_PASS)
> +		goto windup;
> +
> +	if (sigsetjmp(sig_escape, 1) == 0)
> +		*q; /* Fault, triggering a SIGBUS */
> +	else
> +		sigbus_count++;
> +
> +	if (sigbus_count != 1) {
> +		tst_res(TFAIL, "Didn't SIGBUS after truncate");
> +		goto windup;
> +	}
> +
> +	after_sigbus_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD);
> +
> +	TST_EXP_EQ_LU(initial_rsvd, after_sigbus_rsvd);
> +	if (!TST_PASS)
> +		goto windup;
> +
> +windup:
> +	SAFE_MUNMAP(p, hpage_size);
> +	after_unmap_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD);
> +	tst_res(TINFO, "Reserve count after munmap: %lu", after_unmap_rsvd);

This variable is printed but never checked inside the test.

> +
> +}
> +
> +static void setup(void)
> +{
> +	hpage_size = tst_get_hugepage_size();

Need space here.

> +	fd = tst_creat_unlinked(MNTPOINT, 0, 0600);
> +
> +	struct sigaction sa = {
> +		.sa_handler = sigbus_handler,
> +		.sa_flags = 0,
> +	};
> +
> +	SAFE_SIGACTION(SIGBUS, &sa, NULL);
> +}
> +
> +static void cleanup(void)
> +{
> +	if (fd >= 0)
> +		SAFE_CLOSE(fd);

Pleae use fd != -1 here.


Regards,
--
Andrea Cervesato
SUSE QE Automation Engineer Linux
andrea.cervesato@suse.com

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