[LTP] [PATCH] [PATCH v4] Hugetlb: Migrating libhugetlbfs test truncate_reserve_wraparound.c

[Cyril Hrubis]

Hi!
> +/*\
> + *[Descripiton]
> + *
> + * 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.
> + *
> + */
> +
> +#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, siginfo_t *si LTP_ATTRIBUTE_UNUSED, void *uc LTP_ATTRIBUTE_UNUSED)

Why do we bother with passing SA_SIGINFO to the sigaction() when we
ingnore the parameters later?

> +{
> +	siglongjmp(sig_escape, 17);
> +}
> +
> +static void run_test(void)
> +{
> +
> +	static int sigbus_count;
> +	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;
> +
> +	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_res(TINFO, "Reserve count after map: %lu", after_map_rsvd);

Shouldn't we check that after_mmap_rsvd == initial_rsvd + 1 ?

Also we do have nice macros for assertions so we can do:

        TST_EXP_EQ_LU(initial_rsvd + 1, after_mmap_rsvd);
	if (!TST_PASS)
		goto windup;

And we can use these macros in the rest of the comparsions as well. And
with that we do not need to print the useless
tst_res(TPASS, "Test passed"); message

> +	*q = 0;
> +	after_touch_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD);
> +	tst_res(TINFO, "Reserve count after touch: %lu", after_touch_rsvd);
> +
> +	if (after_touch_rsvd != initial_rsvd) {
> +		tst_res(TFAIL, "Reserved after touch %lu instead of %lu", after_touch_rsvd, initial_rsvd);
> +		goto windup;
> +	}
> +
> +	SAFE_FTRUNCATE(fd, 0);
> +	after_trunc_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD);
> +	tst_res(TINFO, "Reserve count after truncate: %lu", after_trunc_rsvd);
> +
> +	if (after_trunc_rsvd != initial_rsvd) {
> +		tst_res(TFAIL, "Reserved after truncate %lu instead of %lu", after_trunc_rsvd, initial_rsvd);
> +		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_res(TINFO, "Reserve count after sigbus: %lu", after_sigbus_rsvd);
> +
> +	if (after_sigbus_rsvd != initial_rsvd) {
> +		tst_res(TFAIL, "Reserved after SIGBUS %lu instead of %lu", after_sigbus_rsvd, initial_rsvd);
> +		goto windup;
> +	}
> +
> +	tst_res(TPASS, "Test passed!");
> +
> +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);
> +
> +}
> +
> +static void setup(void)
> +{
> +	hpage_size = tst_get_hugepage_size();
> +	fd = tst_creat_unlinked(MNTPOINT, 0, 0600);
> +
> +	struct sigaction sa = {
> +		.sa_sigaction = sigbus_handler,
> +		.sa_flags = SA_SIGINFO,
> +	};
> +
> +	SAFE_SIGACTION(SIGBUS, &sa, NULL);
> +}
> +
> +static void cleanup(void)
> +{
> +	if (fd >= 0)
> +		SAFE_CLOSE(fd);
> +}
> +
> +static struct tst_test test = {
> +	.tags = (struct tst_tag[]) {
> +		{"linux-git", "ebed4bfc8da8"},
> +		{}
> +	},
> +	.needs_root = 1,
> +	.mntpoint = MNTPOINT,
> +	.needs_hugetlbfs = 1,
> +	.hugepages = {4, TST_NEEDS},
> +	.setup = setup,
> +	.cleanup = cleanup,
> +	.test_all = run_test,
> +};
> -- 
> 2.43.5
> 

-- 
Cyril Hrubis
chrubis@suse.cz