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test_xarray: add tests for advanced multi-index use

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Patch series "test_xarray: advanced API multi-index tests", v2.

This is a respin of the test_xarray multi-index tests [0] which use and
demonstrate the advanced API which is used by the page cache.  This should
let folks more easily follow how we use multi-index to support for example
a min order later in the page cache.  It also lets us grow the selftests
to mimic more of what we do in the page cache.


This patch (of 2):

The multi index selftests are great but they don't replicate how we deal
with the page cache exactly, which makes it a bit hard to follow as the
page cache uses the advanced API.

Add tests which use the advanced API, mimicking what we do in the page
cache, while at it, extend the example to do what is needed for min order
support.

[mcgrof@kernel.org: fix soft lockup for advanced-api tests]
  Link: https://lkml.kernel.org/r/20240216194329.840555-1-mcgrof@kernel.org
[akpm@linux-foundation.org: s/i/loops/, make non-static]
[akpm@linux-foundation.org: restore static storage for loop counter]
Link: https://lkml.kernel.org/r/20240131225125.1370598-1-mcgrof@kernel.org
Link: https://lkml.kernel.org/r/20240131225125.1370598-2-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Tested-by: Daniel Gomez <da.gomez@samsung.com>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Luis Chamberlain 2024-01-31 14:51:24 -08:00 committed by Andrew Morton
parent d818c98a52
commit a60cc288a1
1 changed files with 176 additions and 0 deletions
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176
lib/test_xarray.c
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@ -674,6 +674,181 @@ static noinline void check_multi_store(struct xarray *xa)
#endif
}
#ifdef CONFIG_XARRAY_MULTI
/* mimics page cache __filemap_add_folio() */
static noinline void check_xa_multi_store_adv_add(struct xarray *xa,
unsigned long index,
unsigned int order,
void *p)
{
XA_STATE(xas, xa, index);
unsigned int nrpages = 1UL << order;
/* users are responsible for index alignemnt to the order when adding */
XA_BUG_ON(xa, index & (nrpages - 1));
xas_set_order(&xas, index, order);
do {
xas_lock_irq(&xas);
xas_store(&xas, p);
XA_BUG_ON(xa, xas_error(&xas));
XA_BUG_ON(xa, xa_load(xa, index) != p);
xas_unlock_irq(&xas);
} while (xas_nomem(&xas, GFP_KERNEL));
XA_BUG_ON(xa, xas_error(&xas));
}
/* mimics page_cache_delete() */
static noinline void check_xa_multi_store_adv_del_entry(struct xarray *xa,
unsigned long index,
unsigned int order)
{
XA_STATE(xas, xa, index);
xas_set_order(&xas, index, order);
xas_store(&xas, NULL);
xas_init_marks(&xas);
}
static noinline void check_xa_multi_store_adv_delete(struct xarray *xa,
unsigned long index,
unsigned int order)
{
xa_lock_irq(xa);
check_xa_multi_store_adv_del_entry(xa, index, order);
xa_unlock_irq(xa);
}
/* mimics page cache filemap_get_entry() */
static noinline void *test_get_entry(struct xarray *xa, unsigned long index)
{
XA_STATE(xas, xa, index);
void *p;
static unsigned int loops = 0;
rcu_read_lock();
repeat:
xas_reset(&xas);
p = xas_load(&xas);
if (xas_retry(&xas, p))
goto repeat;
rcu_read_unlock();
/*
* This is not part of the page cache, this selftest is pretty
* aggressive and does not want to trust the xarray API but rather
* test it, and for order 20 (4 GiB block size) we can loop over
* over a million entries which can cause a soft lockup. Page cache
* APIs won't be stupid, proper page cache APIs loop over the proper
* order so when using a larger order we skip shared entries.
*/
if (++loops % XA_CHECK_SCHED == 0)
schedule();
return p;
}
static unsigned long some_val = 0xdeadbeef;
static unsigned long some_val_2 = 0xdeaddead;
/* mimics the page cache usage */
static noinline void check_xa_multi_store_adv(struct xarray *xa,
unsigned long pos,
unsigned int order)
{
unsigned int nrpages = 1UL << order;
unsigned long index, base, next_index, next_next_index;
unsigned int i;
index = pos >> PAGE_SHIFT;
base = round_down(index, nrpages);
next_index = round_down(base + nrpages, nrpages);
next_next_index = round_down(next_index + nrpages, nrpages);
check_xa_multi_store_adv_add(xa, base, order, &some_val);
for (i = 0; i < nrpages; i++)
XA_BUG_ON(xa, test_get_entry(xa, base + i) != &some_val);
XA_BUG_ON(xa, test_get_entry(xa, next_index) != NULL);
/* Use order 0 for the next item */
check_xa_multi_store_adv_add(xa, next_index, 0, &some_val_2);
XA_BUG_ON(xa, test_get_entry(xa, next_index) != &some_val_2);
/* Remove the next item */
check_xa_multi_store_adv_delete(xa, next_index, 0);
/* Now use order for a new pointer */
check_xa_multi_store_adv_add(xa, next_index, order, &some_val_2);
for (i = 0; i < nrpages; i++)
XA_BUG_ON(xa, test_get_entry(xa, next_index + i) != &some_val_2);
check_xa_multi_store_adv_delete(xa, next_index, order);
check_xa_multi_store_adv_delete(xa, base, order);
XA_BUG_ON(xa, !xa_empty(xa));
/* starting fresh again */
/* let's test some holes now */
/* hole at base and next_next */
check_xa_multi_store_adv_add(xa, next_index, order, &some_val_2);
for (i = 0; i < nrpages; i++)
XA_BUG_ON(xa, test_get_entry(xa, base + i) != NULL);
for (i = 0; i < nrpages; i++)
XA_BUG_ON(xa, test_get_entry(xa, next_index + i) != &some_val_2);
for (i = 0; i < nrpages; i++)
XA_BUG_ON(xa, test_get_entry(xa, next_next_index + i) != NULL);
check_xa_multi_store_adv_delete(xa, next_index, order);
XA_BUG_ON(xa, !xa_empty(xa));
/* hole at base and next */
check_xa_multi_store_adv_add(xa, next_next_index, order, &some_val_2);
for (i = 0; i < nrpages; i++)
XA_BUG_ON(xa, test_get_entry(xa, base + i) != NULL);
for (i = 0; i < nrpages; i++)
XA_BUG_ON(xa, test_get_entry(xa, next_index + i) != NULL);
for (i = 0; i < nrpages; i++)
XA_BUG_ON(xa, test_get_entry(xa, next_next_index + i) != &some_val_2);
check_xa_multi_store_adv_delete(xa, next_next_index, order);
XA_BUG_ON(xa, !xa_empty(xa));
}
#endif
static noinline void check_multi_store_advanced(struct xarray *xa)
{
#ifdef CONFIG_XARRAY_MULTI
unsigned int max_order = IS_ENABLED(CONFIG_XARRAY_MULTI) ? 20 : 1;
unsigned long end = ULONG_MAX/2;
unsigned long pos, i;
/*
* About 117 million tests below.
*/
for (pos = 7; pos < end; pos = (pos * pos) + 564) {
for (i = 0; i < max_order; i++) {
check_xa_multi_store_adv(xa, pos, i);
check_xa_multi_store_adv(xa, pos + 157, i);
}
}
#endif
}
static noinline void check_xa_alloc_1(struct xarray *xa, unsigned int base)
{
int i;
@ -1804,6 +1979,7 @@ static int xarray_checks(void)
check_reserve(&array);
check_reserve(&xa0);
check_multi_store(&array);
check_multi_store_advanced(&array);
check_get_order(&array);
check_xa_alloc();
check_find(&array);