From e2ae9cf39f8806d2d8f5eb0a22ba511804a804ec Mon Sep 17 00:00:00 2001 From: Wei Yang Date: Fri, 12 Jul 2024 03:51:38 +0000 Subject: tools/testing: abstract two init.h into common include directory Currently we have two test suits define its own init.h. This is a little redundant. Let's create a init.h in common include directory and merge these two into it. Signed-off-by: Wei Yang CC: Mike Rapoport CC: Liam R. Howlett Link: https://lore.kernel.org/r/20240712035138.24674-3-richard.weiyang@gmail.com Signed-off-by: Mike Rapoport (Microsoft) --- tools/testing/radix-tree/maple.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/testing/radix-tree/maple.c') diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c index cd1cf05503b4..3437292babff 100644 --- a/tools/testing/radix-tree/maple.c +++ b/tools/testing/radix-tree/maple.c @@ -14,7 +14,7 @@ #include "test.h" #include #include -#include "linux/init.h" +#include #define module_init(x) #define module_exit(x) -- cgit From 617f8e4d76b81361884db852005f519012ddd244 Mon Sep 17 00:00:00 2001 From: Sidhartha Kumar Date: Mon, 12 Aug 2024 15:05:43 -0400 Subject: maple_tree: add test to replicate low memory race conditions Add new callback fields to the userspace implementation of struct kmem_cache. This allows for executing callback functions in order to further test low memory scenarios where node allocation is retried. This callback can help test race conditions by calling a function when a low memory event is tested. Link: https://lkml.kernel.org/r/20240812190543.71967-2-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar Reviewed-by: Liam R. Howlett Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- tools/testing/radix-tree/maple.c | 63 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) (limited to 'tools/testing/radix-tree/maple.c') diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c index cd1cf05503b4..ef5b83cf94ea 100644 --- a/tools/testing/radix-tree/maple.c +++ b/tools/testing/radix-tree/maple.c @@ -36224,6 +36224,65 @@ static noinline void __init check_mtree_dup(struct maple_tree *mt) extern void test_kmem_cache_bulk(void); +/* callback function used for check_nomem_writer_race() */ +static void writer2(void *maple_tree) +{ + struct maple_tree *mt = (struct maple_tree *)maple_tree; + MA_STATE(mas, mt, 6, 10); + + mtree_lock(mas.tree); + mas_store(&mas, xa_mk_value(0xC)); + mas_destroy(&mas); + mtree_unlock(mas.tree); +} + +/* + * check_nomem_writer_race() - test a possible race in the mas_nomem() path + * @mt: The tree to build. + * + * There is a possible race condition in low memory conditions when mas_nomem() + * gives up its lock. A second writer can chagne the entry that the primary + * writer executing the mas_nomem() path is modifying. This test recreates this + * scenario to ensure we are handling it correctly. + */ +static void check_nomem_writer_race(struct maple_tree *mt) +{ + MA_STATE(mas, mt, 0, 5); + + mt_set_non_kernel(0); + /* setup root with 2 values with NULL in between */ + mtree_store_range(mt, 0, 5, xa_mk_value(0xA), GFP_KERNEL); + mtree_store_range(mt, 6, 10, NULL, GFP_KERNEL); + mtree_store_range(mt, 11, 15, xa_mk_value(0xB), GFP_KERNEL); + + /* setup writer 2 that will trigger the race condition */ + mt_set_private(mt); + mt_set_callback(writer2); + + mtree_lock(mt); + /* erase 0-5 */ + mas_erase(&mas); + + /* index 6-10 should retain the value from writer 2 */ + check_load(mt, 6, xa_mk_value(0xC)); + mtree_unlock(mt); + + /* test for the same race but with mas_store_gfp() */ + mtree_store_range(mt, 0, 5, xa_mk_value(0xA), GFP_KERNEL); + mtree_store_range(mt, 6, 10, NULL, GFP_KERNEL); + + mas_set_range(&mas, 0, 5); + mtree_lock(mt); + mas_store_gfp(&mas, NULL, GFP_KERNEL); + + /* ensure write made by writer 2 is retained */ + check_load(mt, 6, xa_mk_value(0xC)); + + mt_set_private(NULL); + mt_set_callback(NULL); + mtree_unlock(mt); +} + void farmer_tests(void) { struct maple_node *node; @@ -36257,6 +36316,10 @@ void farmer_tests(void) check_dfs_preorder(&tree); mtree_destroy(&tree); + mt_init_flags(&tree, MT_FLAGS_ALLOC_RANGE | MT_FLAGS_USE_RCU); + check_nomem_writer_race(&tree); + mtree_destroy(&tree); + mt_init_flags(&tree, MT_FLAGS_ALLOC_RANGE); check_prealloc(&tree); mtree_destroy(&tree); -- cgit From 5d659bbb52a24f91cc6c0cf546ffcc0faa7e8f1a Mon Sep 17 00:00:00 2001 From: Sidhartha Kumar Date: Wed, 14 Aug 2024 12:19:31 -0400 Subject: maple_tree: introduce mas_wr_store_type() Introduce mas_wr_store_type() which will set the correct store type based on a walk of the tree. In mas_wr_node_store() the <= min_slots condition is changed to < as if new_end is = to mt_min_slots then there is not enough room. mas_prealloc_calc() is also introduced to abstract the calculation used to determine the number of nodes needed for a store operation. In this change a call to mas_reset() is removed in the error case of mas_prealloc(). This is only needed in the MA_STATE_REBALANCE case of mas_destroy(). We can move the call to mas_reset() directly to mas_destroy(). Also, add a test case to validate the order that we check the store type in is correct. This test models a vma expanding and then shrinking which is part of the boot process. Link: https://lkml.kernel.org/r/20240814161944.55347-5-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar Cc: Liam R. Howlett Cc: Matthew Wilcox (Oracle) Cc: Suren Baghdasaryan Signed-off-by: Andrew Morton --- tools/testing/radix-tree/maple.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) (limited to 'tools/testing/radix-tree/maple.c') diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c index ef5b83cf94ea..ad42a36231fb 100644 --- a/tools/testing/radix-tree/maple.c +++ b/tools/testing/radix-tree/maple.c @@ -36283,6 +36283,38 @@ static void check_nomem_writer_race(struct maple_tree *mt) mtree_unlock(mt); } + /* test to simulate expanding a vma from [0x7fffffffe000, 0x7ffffffff000) + * to [0x7ffde4ca1000, 0x7ffffffff000) and then shrinking the vma to + * [0x7ffde4ca1000, 0x7ffde4ca2000) + */ +static inline int check_vma_modification(struct maple_tree *mt) +{ + MA_STATE(mas, mt, 0, 0); + + mtree_lock(mt); + /* vma with old start and old end */ + __mas_set_range(&mas, 0x7fffffffe000, 0x7ffffffff000 - 1); + mas_preallocate(&mas, xa_mk_value(1), GFP_KERNEL); + mas_store_prealloc(&mas, xa_mk_value(1)); + + /* next write occurs partly in previous range [0, 0x7fffffffe000)*/ + mas_prev_range(&mas, 0); + /* expand vma to {0x7ffde4ca1000, 0x7ffffffff000) */ + __mas_set_range(&mas, 0x7ffde4ca1000, 0x7ffffffff000 - 1); + mas_preallocate(&mas, xa_mk_value(1), GFP_KERNEL); + mas_store_prealloc(&mas, xa_mk_value(1)); + + /* shrink vma to [0x7ffde4ca1000, 7ffde4ca2000) */ + __mas_set_range(&mas, 0x7ffde4ca2000, 0x7ffffffff000 - 1); + mas_preallocate(&mas, NULL, GFP_KERNEL); + mas_store_prealloc(&mas, NULL); + mt_dump(mt, mt_dump_hex); + + mas_destroy(&mas); + mtree_unlock(mt); + return 0; +} + void farmer_tests(void) { struct maple_node *node; @@ -36290,6 +36322,10 @@ void farmer_tests(void) mt_dump(&tree, mt_dump_dec); + mt_init_flags(&tree, MT_FLAGS_ALLOC_RANGE | MT_FLAGS_LOCK_EXTERN | MT_FLAGS_USE_RCU); + check_vma_modification(&tree); + mtree_destroy(&tree); + tree.ma_root = xa_mk_value(0); mt_dump(&tree, mt_dump_dec); -- cgit From 3cd9e92e009de9a036cbf9ec27bad33367fca6f3 Mon Sep 17 00:00:00 2001 From: Sidhartha Kumar Date: Wed, 14 Aug 2024 12:19:32 -0400 Subject: maple_tree: remove mas_destroy() from mas_nomem() Separate call to mas_destroy() from mas_nomem() so we can check for no memory errors without destroying the current maple state in mas_store_gfp(). We then add calls to mas_destroy() to callers of mas_nomem(). Link: https://lkml.kernel.org/r/20240814161944.55347-6-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar Reviewed-by: Liam R. Howlett Cc: Matthew Wilcox (Oracle) Cc: Suren Baghdasaryan Signed-off-by: Andrew Morton --- tools/testing/radix-tree/maple.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'tools/testing/radix-tree/maple.c') diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c index ad42a36231fb..c5b00aca9def 100644 --- a/tools/testing/radix-tree/maple.c +++ b/tools/testing/radix-tree/maple.c @@ -120,7 +120,7 @@ static noinline void __init check_new_node(struct maple_tree *mt) MT_BUG_ON(mt, mas.alloc->slot[0] == NULL); mas_push_node(&mas, mn); mas_reset(&mas); - mas_nomem(&mas, GFP_KERNEL); /* free */ + mas_destroy(&mas); mtree_unlock(mt); @@ -144,7 +144,7 @@ static noinline void __init check_new_node(struct maple_tree *mt) mn->parent = ma_parent_ptr(mn); ma_free_rcu(mn); mas.status = ma_start; - mas_nomem(&mas, GFP_KERNEL); + mas_destroy(&mas); /* Allocate 3 nodes, will fail. */ mas_node_count(&mas, 3); /* Drop the lock and allocate 3 nodes. */ @@ -161,7 +161,7 @@ static noinline void __init check_new_node(struct maple_tree *mt) MT_BUG_ON(mt, mas_allocated(&mas) != 3); /* Free. */ mas_reset(&mas); - mas_nomem(&mas, GFP_KERNEL); + mas_destroy(&mas); /* Set allocation request to 1. */ mas_set_alloc_req(&mas, 1); @@ -277,6 +277,7 @@ static noinline void __init check_new_node(struct maple_tree *mt) } mas_reset(&mas); MT_BUG_ON(mt, mas_nomem(&mas, GFP_KERNEL)); + mas_destroy(&mas); } @@ -299,7 +300,7 @@ static noinline void __init check_new_node(struct maple_tree *mt) } MT_BUG_ON(mt, mas_allocated(&mas) != total); mas_reset(&mas); - mas_nomem(&mas, GFP_KERNEL); /* Free. */ + mas_destroy(&mas); /* Free. */ MT_BUG_ON(mt, mas_allocated(&mas) != 0); for (i = 1; i < 128; i++) { @@ -35847,6 +35848,7 @@ static noinline void __init check_nomem(struct maple_tree *mt) mas_store(&ms, &ms); /* insert 1 -> &ms */ mas_nomem(&ms, GFP_KERNEL); /* Node allocated in here. */ mtree_unlock(mt); + mas_destroy(&ms); mtree_destroy(mt); } -- cgit