From a60cc288a1a2604bd86d3df129f269887018c3cb Mon Sep 17 00:00:00 2001 From: Luis Chamberlain Date: Wed, 31 Jan 2024 14:51:24 -0800 Subject: test_xarray: add tests for advanced multi-index use 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 Tested-by: Daniel Gomez Cc: Darrick J. Wong Cc: Dave Chinner Cc: Hannes Reinecke Cc: Matthew Wilcox Cc: Pankaj Raghav Signed-off-by: Andrew Morton --- lib/test_xarray.c | 176 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 176 insertions(+) (limited to 'lib/test_xarray.c') diff --git a/lib/test_xarray.c b/lib/test_xarray.c index e77d4856442c..1050e9113d2a 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -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); -- cgit v1.2.3 From e777ae44e33e48ad01bfdc978076b03c1f091b4f Mon Sep 17 00:00:00 2001 From: Daniel Gomez Date: Wed, 31 Jan 2024 14:51:25 -0800 Subject: XArray: add cmpxchg order test XArray multi-index entries do not keep track of the order stored once the entry is being marked as used with cmpxchg (conditionally replaced with NULL). Add a test to check the order is actually lost. The test also verifies the order and entries for all the tied indexes before and after the NULL replacement with xa_cmpxchg. Add another entry at 1 << order that keeps the node around and the order information for the NULL-entry after xa_cmpxchg. Link: https://lkml.kernel.org/r/20240131225125.1370598-3-mcgrof@kernel.org Signed-off-by: Daniel Gomez Signed-off-by: Luis Chamberlain Cc: Darrick J. Wong Cc: Dave Chinner Cc: Hannes Reinecke Cc: Matthew Wilcox Cc: Pankaj Raghav Signed-off-by: Andrew Morton --- lib/test_xarray.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) (limited to 'lib/test_xarray.c') diff --git a/lib/test_xarray.c b/lib/test_xarray.c index 1050e9113d2a..ebe2af2e072d 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -423,6 +423,59 @@ static noinline void check_cmpxchg(struct xarray *xa) XA_BUG_ON(xa, !xa_empty(xa)); } +static noinline void check_cmpxchg_order(struct xarray *xa) +{ +#ifdef CONFIG_XARRAY_MULTI + void *FIVE = xa_mk_value(5); + unsigned int i, order = 3; + + XA_BUG_ON(xa, xa_store_order(xa, 0, order, FIVE, GFP_KERNEL)); + + /* Check entry FIVE has the order saved */ + XA_BUG_ON(xa, xa_get_order(xa, xa_to_value(FIVE)) != order); + + /* Check all the tied indexes have the same entry and order */ + for (i = 0; i < (1 << order); i++) { + XA_BUG_ON(xa, xa_load(xa, i) != FIVE); + XA_BUG_ON(xa, xa_get_order(xa, i) != order); + } + + /* Ensure that nothing is stored at index '1 << order' */ + XA_BUG_ON(xa, xa_load(xa, 1 << order) != NULL); + + /* + * Additionally, keep the node information and the order at + * '1 << order' + */ + XA_BUG_ON(xa, xa_store_order(xa, 1 << order, order, FIVE, GFP_KERNEL)); + for (i = (1 << order); i < (1 << order) + (1 << order) - 1; i++) { + XA_BUG_ON(xa, xa_load(xa, i) != FIVE); + XA_BUG_ON(xa, xa_get_order(xa, i) != order); + } + + /* Conditionally replace FIVE entry at index '0' with NULL */ + XA_BUG_ON(xa, xa_cmpxchg(xa, 0, FIVE, NULL, GFP_KERNEL) != FIVE); + + /* Verify the order is lost at FIVE (and old) entries */ + XA_BUG_ON(xa, xa_get_order(xa, xa_to_value(FIVE)) != 0); + + /* Verify the order and entries are lost in all the tied indexes */ + for (i = 0; i < (1 << order); i++) { + XA_BUG_ON(xa, xa_load(xa, i) != NULL); + XA_BUG_ON(xa, xa_get_order(xa, i) != 0); + } + + /* Verify node and order are kept at '1 << order' */ + for (i = (1 << order); i < (1 << order) + (1 << order) - 1; i++) { + XA_BUG_ON(xa, xa_load(xa, i) != FIVE); + XA_BUG_ON(xa, xa_get_order(xa, i) != order); + } + + xa_store_order(xa, 0, BITS_PER_LONG - 1, NULL, GFP_KERNEL); + XA_BUG_ON(xa, !xa_empty(xa)); +#endif +} + static noinline void check_reserve(struct xarray *xa) { void *entry; @@ -1976,6 +2029,7 @@ static int xarray_checks(void) check_xas_erase(&array); check_insert(&array); check_cmpxchg(&array); + check_cmpxchg_order(&array); check_reserve(&array); check_reserve(&xa0); check_multi_store(&array); -- cgit v1.2.3