[PATCH 0/3] align maple tree write paths

[PATCH 0/3] align maple tree write paths

[Sidhartha Kumar]

This series modifies the store paths in mas_store_gfp() and mas_erase() to
use the newly refined preallocation calculation before their calls to 
mas_wr_store_entry(). This will avoid having to do worst case calculations.

Patch 1 abstracts the calculation outside of mas_preallocate() so it can
be used externally.

Patch 2 modifies the write path in mas_store_gfp() to use preallocations
and patch 3 does this in mas_erase().

The motivation for this series is part of the Maple Tree work list[1].


========== TESTING ==============
Testing was done with the maple tree test suite.
maple_tree: 570172962 of 570172962 tests passed

rebased on mm-unstable 10/09/23

[1]: https://lore.kernel.org/linux-mm/20230912172845.o54szwf33hc6p7ee@revolver/T/

Sidhartha Kumar (3):
  maple_tree: introduce mas_prealloc_calc()
  maple_tree: use preallocations in mas_store_gfp()
  maple_tree: use preallocations in mas_erase()

 lib/maple_tree.c | 128 ++++++++++++++++++++++++++++++++---------------
 1 file changed, 88 insertions(+), 40 deletions(-)

-- 
2.41.0

[PATCH 1/3] maple_tree: introduce mas_prealloc_calc()

[Sidhartha Kumar]

Abstract the calculation used to determine the number of nodes needed for
a store operation into a separate function: mas_prealloc_calc().

Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
---
 lib/maple_tree.c | 85 ++++++++++++++++++++++++++++--------------------
 1 file changed, 50 insertions(+), 35 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 0e00a84e8e8f..e239197a57fc 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -5418,6 +5418,54 @@ void *mas_store(struct ma_state *mas, void *entry)
 }
 EXPORT_SYMBOL_GPL(mas_store);
 
+/**
+ * mas_prealloc_calc() - Calculate number of nodes needed for a
+ * store operation.
+ * @wr_mas: The maple write state
+ *
+ * Return: Number of nodes required for preallocation.
+ */
+int mas_prealloc_calc(struct ma_wr_state *wr_mas)
+{
+	struct ma_state *mas = wr_mas->mas;
+	unsigned char node_size;
+
+	if (unlikely(!mas->index && mas->last == ULONG_MAX))
+		return 1;
+
+	/* Root expand */
+	if (unlikely(mas_is_none(mas) || mas_is_ptr(mas)))
+		return 1;
+
+	if (unlikely(!mas_wr_walk(wr_mas))) {
+		/* Spanning store, use worst case for now */
+		return 1 + mas_mt_height(mas) * 3;
+	}
+
+	/* At this point, we are at the leaf node that needs to be altered. */
+	/* Exact fit, no nodes needed. */
+	if (wr_mas->r_min == mas->index && wr_mas->r_max == mas->last)
+		return 0;
+
+	mas_wr_end_piv(wr_mas);
+	node_size = mas_wr_new_end(wr_mas);
+	if (node_size >= mt_slots[wr_mas->type]) {
+		/* Split, worst case for now. */
+		return 1 + mas_mt_height(mas) * 2;
+	}
+
+	/* New root needs a singe node */
+	if (unlikely(mte_is_root(mas->node)))
+		return 1;
+
+	/* Potential spanning rebalance collapsing a node, use worst-case */
+	if (node_size  - 1 <= mt_min_slots[wr_mas->type])
+		return mas_mt_height(mas) * 2 - 1;
+
+	/* node store, slot store needs one node */
+	return 1;
+}
+
 /**
  * mas_store_gfp() - Store a value into the tree.
  * @mas: The maple state
@@ -5474,49 +5522,16 @@ EXPORT_SYMBOL_GPL(mas_store_prealloc);
 int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp)
 {
 	MA_WR_STATE(wr_mas, mas, entry);
-	unsigned char node_size;
 	int request = 1;
 	int ret;
 
-
-	if (unlikely(!mas->index && mas->last == ULONG_MAX))
-		goto ask_now;
-
 	mas_wr_store_setup(&wr_mas);
 	wr_mas.content = mas_start(mas);
-	/* Root expand */
-	if (unlikely(mas_is_none(mas) || mas_is_ptr(mas)))
-		goto ask_now;
 
-	if (unlikely(!mas_wr_walk(&wr_mas))) {
-		/* Spanning store, use worst case for now */
-		request = 1 + mas_mt_height(mas) * 3;
-		goto ask_now;
-	}
-
-	/* At this point, we are at the leaf node that needs to be altered. */
-	/* Exact fit, no nodes needed. */
-	if (wr_mas.r_min == mas->index && wr_mas.r_max == mas->last)
+	request = mas_prealloc_calc(&wr_mas);
+	if (!request)
 		return 0;
 
-	mas_wr_end_piv(&wr_mas);
-	node_size = mas_wr_new_end(&wr_mas);
-	if (node_size >= mt_slots[wr_mas.type]) {
-		/* Split, worst case for now. */
-		request = 1 + mas_mt_height(mas) * 2;
-		goto ask_now;
-	}
-
-	/* New root needs a singe node */
-	if (unlikely(mte_is_root(mas->node)))
-		goto ask_now;
-
-	/* Potential spanning rebalance collapsing a node, use worst-case */
-	if (node_size  - 1 <= mt_min_slots[wr_mas.type])
-		request = mas_mt_height(mas) * 2 - 1;
-
-	/* node store, slot store needs one node */
-ask_now:
 	mas_node_count_gfp(mas, request, gfp);
 	mas->mas_flags |= MA_STATE_PREALLOC;
 	if (likely(!mas_is_err(mas)))
-- 
2.41.0

Re: [PATCH 1/3] maple_tree: introduce mas_prealloc_calc()

[kernel test robot]

Hi Sidhartha,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]
[also build test WARNING on linus/master v6.6-rc5 next-20231009]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Sidhartha-Kumar/maple_tree-introduce-mas_prealloc_calc/20231010-041859
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20231009201639.920512-2-sidhartha.kumar%40oracle.com
patch subject: [PATCH 1/3] maple_tree: introduce mas_prealloc_calc()
config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20231010/202310100603.qsn3ruBx-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231010/202310100603.qsn3ruBx-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202310100603.qsn3ruBx-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> lib/maple_tree.c:5428:5: warning: no previous prototype for 'mas_prealloc_calc' [-Wmissing-prototypes]
    5428 | int mas_prealloc_calc(struct ma_wr_state *wr_mas)
         |     ^~~~~~~~~~~~~~~~~


vim +/mas_prealloc_calc +5428 lib/maple_tree.c

  5420	
  5421	/**
  5422	 * mas_prealloc_calc() - Calculate number of nodes needed for a
  5423	 * store operation.
  5424	 * @wr_mas: The maple write state
  5425	 *
  5426	 * Return: Number of nodes required for preallocation.
  5427	 */
> 5428	int mas_prealloc_calc(struct ma_wr_state *wr_mas)
  5429	{
  5430		struct ma_state *mas = wr_mas->mas;
  5431		unsigned char node_size;
  5432	
  5433		if (unlikely(!mas->index && mas->last == ULONG_MAX))
  5434			return 1;
  5435	
  5436		/* Root expand */
  5437		if (unlikely(mas_is_none(mas) || mas_is_ptr(mas)))
  5438			return 1;
  5439	
  5440		if (unlikely(!mas_wr_walk(wr_mas))) {
  5441			/* Spanning store, use worst case for now */
  5442			return 1 + mas_mt_height(mas) * 3;
  5443		}
  5444	
  5445		/* At this point, we are at the leaf node that needs to be altered. */
  5446		/* Exact fit, no nodes needed. */
  5447		if (wr_mas->r_min == mas->index && wr_mas->r_max == mas->last)
  5448			return 0;
  5449	
  5450		mas_wr_end_piv(wr_mas);
  5451		node_size = mas_wr_new_end(wr_mas);
  5452		if (node_size >= mt_slots[wr_mas->type]) {
  5453			/* Split, worst case for now. */
  5454			return 1 + mas_mt_height(mas) * 2;
  5455		}
  5456	
  5457		/* New root needs a singe node */
  5458		if (unlikely(mte_is_root(mas->node)))
  5459			return 1;
  5460	
  5461		/* Potential spanning rebalance collapsing a node, use worst-case */
  5462		if (node_size  - 1 <= mt_min_slots[wr_mas->type])
  5463			return mas_mt_height(mas) * 2 - 1;
  5464	
  5465		/* node store, slot store needs one node */
  5466		return 1;
  5467	}
  5468	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 1/3] maple_tree: introduce mas_prealloc_calc()

[Sidhartha Kumar]

On 10/9/23 3:25 PM, kernel test robot wrote:
> Hi Sidhartha,
> 
> kernel test robot noticed the following build warnings:
> 
> [auto build test WARNING on akpm-mm/mm-everything]
> [also build test WARNING on linus/master v6.6-rc5 next-20231009]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Sidhartha-Kumar/maple_tree-introduce-mas_prealloc_calc/20231010-041859
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
> patch link:    https://lore.kernel.org/r/20231009201639.920512-2-sidhartha.kumar%40oracle.com
> patch subject: [PATCH 1/3] maple_tree: introduce mas_prealloc_calc()
> config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20231010/202310100603.qsn3ruBx-lkp@intel.com/config)
> compiler: m68k-linux-gcc (GCC) 13.2.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231010/202310100603.qsn3ruBx-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202310100603.qsn3ruBx-lkp@intel.com/
> 
> All warnings (new ones prefixed by >>):
> 
>>> lib/maple_tree.c:5428:5: warning: no previous prototype for 'mas_prealloc_calc' [-Wmissing-prototypes]
>      5428 | int mas_prealloc_calc(struct ma_wr_state *wr_mas)
>           |     ^~~~~~~~~~~~~~~~~
> 
> 
> vim +/mas_prealloc_calc +5428 lib/maple_tree.c
> 
>    5420	
>    5421	/**
>    5422	 * mas_prealloc_calc() - Calculate number of nodes needed for a
>    5423	 * store operation.
>    5424	 * @wr_mas: The maple write state
>    5425	 *
>    5426	 * Return: Number of nodes required for preallocation.
>    5427	 */
>> 5428	int mas_prealloc_calc(struct ma_wr_state *wr_mas)

Adding static inline should fix this compilation error.

>    5429	{
>    5430		struct ma_state *mas = wr_mas->mas;
>    5431		unsigned char node_size;
>    5432	
>    5433		if (unlikely(!mas->index && mas->last == ULONG_MAX))
>    5434			return 1;
>    5435	
>    5436		/* Root expand */
>    5437		if (unlikely(mas_is_none(mas) || mas_is_ptr(mas)))
>    5438			return 1;
>    5439	
>    5440		if (unlikely(!mas_wr_walk(wr_mas))) {
>    5441			/* Spanning store, use worst case for now */
>    5442			return 1 + mas_mt_height(mas) * 3;
>    5443		}
>    5444	
>    5445		/* At this point, we are at the leaf node that needs to be altered. */
>    5446		/* Exact fit, no nodes needed. */
>    5447		if (wr_mas->r_min == mas->index && wr_mas->r_max == mas->last)
>    5448			return 0;
>    5449	
>    5450		mas_wr_end_piv(wr_mas);
>    5451		node_size = mas_wr_new_end(wr_mas);
>    5452		if (node_size >= mt_slots[wr_mas->type]) {
>    5453			/* Split, worst case for now. */
>    5454			return 1 + mas_mt_height(mas) * 2;
>    5455		}
>    5456	
>    5457		/* New root needs a singe node */
>    5458		if (unlikely(mte_is_root(mas->node)))
>    5459			return 1;
>    5460	
>    5461		/* Potential spanning rebalance collapsing a node, use worst-case */
>    5462		if (node_size  - 1 <= mt_min_slots[wr_mas->type])
>    5463			return mas_mt_height(mas) * 2 - 1;
>    5464	
>    5465		/* node store, slot store needs one node */
>    5466		return 1;
>    5467	}
>    5468	
> 

Re: [PATCH 1/3] maple_tree: introduce mas_prealloc_calc()

[kernel test robot]

Hi Sidhartha,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]
[also build test WARNING on linus/master v6.6-rc5 next-20231010]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Sidhartha-Kumar/maple_tree-introduce-mas_prealloc_calc/20231010-041859
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20231009201639.920512-2-sidhartha.kumar%40oracle.com
patch subject: [PATCH 1/3] maple_tree: introduce mas_prealloc_calc()
config: um-allnoconfig (https://download.01.org/0day-ci/archive/20231010/202310101854.kMSUyzOr-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231010/202310101854.kMSUyzOr-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202310101854.kMSUyzOr-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> lib/maple_tree.c:5428:5: warning: no previous prototype for function 'mas_prealloc_calc' [-Wmissing-prototypes]
    5428 | int mas_prealloc_calc(struct ma_wr_state *wr_mas)
         |     ^
   lib/maple_tree.c:5428:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
    5428 | int mas_prealloc_calc(struct ma_wr_state *wr_mas)
         | ^
         | static 
   lib/maple_tree.c:348:21: warning: unused function 'mte_set_full' [-Wunused-function]
     348 | static inline void *mte_set_full(const struct maple_enode *node)
         |                     ^
   lib/maple_tree.c:353:21: warning: unused function 'mte_clear_full' [-Wunused-function]
     353 | static inline void *mte_clear_full(const struct maple_enode *node)
         |                     ^
   lib/maple_tree.c:358:20: warning: unused function 'mte_has_null' [-Wunused-function]
     358 | static inline bool mte_has_null(const struct maple_enode *node)
         |                    ^
   lib/maple_tree.c:689:29: warning: unused function 'mas_pivot' [-Wunused-function]
     689 | static inline unsigned long mas_pivot(struct ma_state *mas, unsigned char piv)
         |                             ^
   lib/maple_tree.c:4201:20: warning: stack frame size (1032) exceeds limit (1024) in 'mas_wr_modify' [-Wframe-larger-than]
    4201 | static inline void mas_wr_modify(struct ma_wr_state *wr_mas)
         |                    ^
   6 warnings generated.


vim +/mas_prealloc_calc +5428 lib/maple_tree.c

  5420	
  5421	/**
  5422	 * mas_prealloc_calc() - Calculate number of nodes needed for a
  5423	 * store operation.
  5424	 * @wr_mas: The maple write state
  5425	 *
  5426	 * Return: Number of nodes required for preallocation.
  5427	 */
> 5428	int mas_prealloc_calc(struct ma_wr_state *wr_mas)
  5429	{
  5430		struct ma_state *mas = wr_mas->mas;
  5431		unsigned char node_size;
  5432	
  5433		if (unlikely(!mas->index && mas->last == ULONG_MAX))
  5434			return 1;
  5435	
  5436		/* Root expand */
  5437		if (unlikely(mas_is_none(mas) || mas_is_ptr(mas)))
  5438			return 1;
  5439	
  5440		if (unlikely(!mas_wr_walk(wr_mas))) {
  5441			/* Spanning store, use worst case for now */
  5442			return 1 + mas_mt_height(mas) * 3;
  5443		}
  5444	
  5445		/* At this point, we are at the leaf node that needs to be altered. */
  5446		/* Exact fit, no nodes needed. */
  5447		if (wr_mas->r_min == mas->index && wr_mas->r_max == mas->last)
  5448			return 0;
  5449	
  5450		mas_wr_end_piv(wr_mas);
  5451		node_size = mas_wr_new_end(wr_mas);
  5452		if (node_size >= mt_slots[wr_mas->type]) {
  5453			/* Split, worst case for now. */
  5454			return 1 + mas_mt_height(mas) * 2;
  5455		}
  5456	
  5457		/* New root needs a singe node */
  5458		if (unlikely(mte_is_root(mas->node)))
  5459			return 1;
  5460	
  5461		/* Potential spanning rebalance collapsing a node, use worst-case */
  5462		if (node_size  - 1 <= mt_min_slots[wr_mas->type])
  5463			return mas_mt_height(mas) * 2 - 1;
  5464	
  5465		/* node store, slot store needs one node */
  5466		return 1;
  5467	}
  5468	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 1/3] maple_tree: introduce mas_prealloc_calc()

[kernel test robot]

Hi Sidhartha,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]
[also build test WARNING on linus/master v6.6-rc6 next-20231017]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Sidhartha-Kumar/maple_tree-introduce-mas_prealloc_calc/20231010-041859
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20231009201639.920512-2-sidhartha.kumar%40oracle.com
patch subject: [PATCH 1/3] maple_tree: introduce mas_prealloc_calc()
config: i386-randconfig-061-20231018 (https://download.01.org/0day-ci/archive/20231018/202310181030.sYP91twn-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231018/202310181030.sYP91twn-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202310181030.sYP91twn-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> lib/maple_tree.c:5428:5: sparse: sparse: symbol 'mas_prealloc_calc' was not declared. Should it be static?

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

[PATCH 2/3] maple_tree: use preallocations in mas_store_gfp()

[Sidhartha Kumar]

Preallocate maple nodes before call to mas_wr_store_entry(). If a new
node is not needed, go directly to mas_wr_store_entry(), otherwise
allocate the needed nodes and set the MA_STATE_PREALLOC flag.

Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
---
 lib/maple_tree.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index e239197a57fc..25ae66e585f4 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -5478,17 +5478,33 @@ int mas_prealloc_calc(struct ma_wr_state *wr_mas)
 int mas_store_gfp(struct ma_state *mas, void *entry, gfp_t gfp)
 {
 	MA_WR_STATE(wr_mas, mas, entry);
+	int request;
 
 	mas_wr_store_setup(&wr_mas);
-	trace_ma_write(__func__, mas, 0, entry);
-retry:
+	wr_mas.content = mas_start(mas);
+
+	request = mas_prealloc_calc(&wr_mas);
+	if (!request)
+		goto store_entry;
+
+	mas_node_count_gfp(mas, request, gfp);
+	if (unlikely(mas_is_err(mas))) {
+		mas_set_alloc_req(mas, 0);
+		mas_destroy(mas);
+		mas_reset(mas);
+		return xa_err(mas->node);
+	}
+	mas->mas_flags |= MA_STATE_PREALLOC;
+
+store_entry:
 	mas_wr_store_entry(&wr_mas);
 	if (unlikely(mas_nomem(mas, gfp)))
-		goto retry;
+		goto store_entry;
 
 	if (unlikely(mas_is_err(mas)))
 		return xa_err(mas->node);
 
+	trace_ma_write(__func__, mas, 0, entry);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(mas_store_gfp);
-- 
2.41.0

Re: [PATCH 2/3] maple_tree: use preallocations in mas_store_gfp()

[Peng Zhang]

Hi,

在 2023/10/10 04:16, Sidhartha Kumar 写道:
> Preallocate maple nodes before call to mas_wr_store_entry(). If a new
> node is not needed, go directly to mas_wr_store_entry(), otherwise
> allocate the needed nodes and set the MA_STATE_PREALLOC flag.
> 
> Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
> ---
>   lib/maple_tree.c | 22 +++++++++++++++++++---
>   1 file changed, 19 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
> index e239197a57fc..25ae66e585f4 100644
> --- a/lib/maple_tree.c
> +++ b/lib/maple_tree.c
> @@ -5478,17 +5478,33 @@ int mas_prealloc_calc(struct ma_wr_state *wr_mas)
>   int mas_store_gfp(struct ma_state *mas, void *entry, gfp_t gfp)
>   {
>   	MA_WR_STATE(wr_mas, mas, entry);
> +	int request;
>   
>   	mas_wr_store_setup(&wr_mas);
> -	trace_ma_write(__func__, mas, 0, entry);
> -retry:
> +	wr_mas.content = mas_start(mas);
> +
> +	request = mas_prealloc_calc(&wr_mas);
mas_wr_store_entry() does something similar to mas_prealloc_calc().
Now, making it do it twice would incur additional overhead.
We encountered this issue while optimizing preallocation, but it
hasn't been resolved yet. Previously, this problem only occurred
when using mas_preallocate(). Now, this change would bring this
impact to all write operations on maple tree. What do you think
about it?

Thanks,
Peng
> +	if (!request)
> +		goto store_entry;
> +
> +	mas_node_count_gfp(mas, request, gfp);
> +	if (unlikely(mas_is_err(mas))) {
> +		mas_set_alloc_req(mas, 0);
> +		mas_destroy(mas);
> +		mas_reset(mas);
> +		return xa_err(mas->node);
> +	}
> +	mas->mas_flags |= MA_STATE_PREALLOC;
> +
> +store_entry:
>   	mas_wr_store_entry(&wr_mas);
>   	if (unlikely(mas_nomem(mas, gfp)))
> -		goto retry;
> +		goto store_entry;
>   
>   	if (unlikely(mas_is_err(mas)))
>   		return xa_err(mas->node);
>   
> +	trace_ma_write(__func__, mas, 0, entry);
>   	return 0;
>   }
>   EXPORT_SYMBOL_GPL(mas_store_gfp);

Re: [PATCH 2/3] maple_tree: use preallocations in mas_store_gfp()

[Sidhartha Kumar]

On 10/9/23 8:03 PM, Peng Zhang wrote:
> Hi,
> 
> 在 2023/10/10 04:16, Sidhartha Kumar 写道:
>> Preallocate maple nodes before call to mas_wr_store_entry(). If a new
>> node is not needed, go directly to mas_wr_store_entry(), otherwise
>> allocate the needed nodes and set the MA_STATE_PREALLOC flag.
>>
>> Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
>> ---
>>   lib/maple_tree.c | 22 +++++++++++++++++++---
>>   1 file changed, 19 insertions(+), 3 deletions(-)
>>
>> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
>> index e239197a57fc..25ae66e585f4 100644
>> --- a/lib/maple_tree.c
>> +++ b/lib/maple_tree.c
>> @@ -5478,17 +5478,33 @@ int mas_prealloc_calc(struct ma_wr_state *wr_mas)
>>   int mas_store_gfp(struct ma_state *mas, void *entry, gfp_t gfp)
>>   {
>>       MA_WR_STATE(wr_mas, mas, entry);
>> +    int request;
>>       mas_wr_store_setup(&wr_mas);
>> -    trace_ma_write(__func__, mas, 0, entry);
>> -retry:
>> +    wr_mas.content = mas_start(mas);
>> +
>> +    request = mas_prealloc_calc(&wr_mas);
> mas_wr_store_entry() does something similar to mas_prealloc_calc().
> Now, making it do it twice would incur additional overhead.
> We encountered this issue while optimizing preallocation, but it
> hasn't been resolved yet. Previously, this problem only occurred
> when using mas_preallocate(). Now, this change would bring this
> impact to all write operations on maple tree. What do you think
> about it?
> 

After talking to Liam, I will have to implement the store type enum 
feature on the Maple Tree Work list so that mas_prealloc_calc() can 
start a partial walk and write that information to the enum. 
mas_wr_store_entry() can then read that enum to continue the walk that 
was already started rather than having to redo the whole walk. This 
could also be used in mas_preallocate(). Do you have any suggestions for 
the implementation of this enum?

Thanks,
Sid

> Thanks,
> Peng
>> +    if (!request)
>> +        goto store_entry;
>> +
>> +    mas_node_count_gfp(mas, request, gfp);
>> +    if (unlikely(mas_is_err(mas))) {
>> +        mas_set_alloc_req(mas, 0);
>> +        mas_destroy(mas);
>> +        mas_reset(mas);
>> +        return xa_err(mas->node);
>> +    }
>> +    mas->mas_flags |= MA_STATE_PREALLOC;
>> +
>> +store_entry:
>>       mas_wr_store_entry(&wr_mas);
>>       if (unlikely(mas_nomem(mas, gfp)))
>> -        goto retry;
>> +        goto store_entry;
>>       if (unlikely(mas_is_err(mas)))
>>           return xa_err(mas->node);
>> +    trace_ma_write(__func__, mas, 0, entry);
>>       return 0;
>>   }
>>   EXPORT_SYMBOL_GPL(mas_store_gfp);
> 

Re: [PATCH 2/3] maple_tree: use preallocations in mas_store_gfp()

[Peng Zhang]

在 2023/10/11 08:17, Sidhartha Kumar 写道:
> On 10/9/23 8:03 PM, Peng Zhang wrote:
>> Hi,
>>
>> 在 2023/10/10 04:16, Sidhartha Kumar 写道:
>>> Preallocate maple nodes before call to mas_wr_store_entry(). If a new
>>> node is not needed, go directly to mas_wr_store_entry(), otherwise
>>> allocate the needed nodes and set the MA_STATE_PREALLOC flag.
>>>
>>> Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
>>> ---
>>>   lib/maple_tree.c | 22 +++++++++++++++++++---
>>>   1 file changed, 19 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
>>> index e239197a57fc..25ae66e585f4 100644
>>> --- a/lib/maple_tree.c
>>> +++ b/lib/maple_tree.c
>>> @@ -5478,17 +5478,33 @@ int mas_prealloc_calc(struct ma_wr_state *wr_mas)
>>>   int mas_store_gfp(struct ma_state *mas, void *entry, gfp_t gfp)
>>>   {
>>>       MA_WR_STATE(wr_mas, mas, entry);
>>> +    int request;
>>>       mas_wr_store_setup(&wr_mas);
>>> -    trace_ma_write(__func__, mas, 0, entry);
>>> -retry:
>>> +    wr_mas.content = mas_start(mas);
>>> +
>>> +    request = mas_prealloc_calc(&wr_mas);
>> mas_wr_store_entry() does something similar to mas_prealloc_calc().
>> Now, making it do it twice would incur additional overhead.
>> We encountered this issue while optimizing preallocation, but it
>> hasn't been resolved yet. Previously, this problem only occurred
>> when using mas_preallocate(). Now, this change would bring this
>> impact to all write operations on maple tree. What do you think
>> about it?
>>
> 
> After talking to Liam, I will have to implement the store type enum feature on the Maple Tree Work list so that mas_prealloc_calc() can start a partial walk and write that information to the enum. mas_wr_store_entry() can then read that enum to continue the walk that was already started rather than having to redo the whole walk. This could also be used in mas_preallocate(). Do you have any suggestions for the implementation of this enum?
There is another scenario where this enum can be useful,
as seen in the implementation of mas_replace_entry() in [1].
It is a faster alternative to mas_store(), but it is not safe.
If we can determine through the enum while writing the maple
tree that a faster write operation can be performed, it would
be beneficial. Some performance improvements can also be
observed in [1].

[1] https://lore.kernel.org/lkml/49f0181a-55a4-41aa-8596-877560c8b802@bytedance.com/
> 
> Thanks,
> Sid
> 
>> Thanks,
>> Peng
>>> +    if (!request)
>>> +        goto store_entry;
>>> +
>>> +    mas_node_count_gfp(mas, request, gfp);
>>> +    if (unlikely(mas_is_err(mas))) {
>>> +        mas_set_alloc_req(mas, 0);
>>> +        mas_destroy(mas);
>>> +        mas_reset(mas);
>>> +        return xa_err(mas->node);
>>> +    }
>>> +    mas->mas_flags |= MA_STATE_PREALLOC;
>>> +
>>> +store_entry:
>>>       mas_wr_store_entry(&wr_mas);
>>>       if (unlikely(mas_nomem(mas, gfp)))
>>> -        goto retry;
>>> +        goto store_entry;
>>>       if (unlikely(mas_is_err(mas)))
>>>           return xa_err(mas->node);
>>> +    trace_ma_write(__func__, mas, 0, entry);
>>>       return 0;
>>>   }
>>>   EXPORT_SYMBOL_GPL(mas_store_gfp);
>>
> 
> 

Re: [PATCH 2/3] maple_tree: use preallocations in mas_store_gfp()

[Liam R. Howlett]

* Sidhartha Kumar <sidhartha.kumar@oracle.com> [231009 16:16]:
> Preallocate maple nodes before call to mas_wr_store_entry(). If a new
> node is not needed, go directly to mas_wr_store_entry(), otherwise
> allocate the needed nodes and set the MA_STATE_PREALLOC flag.


The way I'd like to see this working is to preallocate nodes prior to
writing, but also to end in a state where we can call the store
operation to continue the operation.  Both of these parts need to be
together in a patch set if they cannot be in the same patch.

Thanks,
Liam

> 
> Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
> ---
>  lib/maple_tree.c | 22 +++++++++++++++++++---
>  1 file changed, 19 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
> index e239197a57fc..25ae66e585f4 100644
> --- a/lib/maple_tree.c
> +++ b/lib/maple_tree.c
> @@ -5478,17 +5478,33 @@ int mas_prealloc_calc(struct ma_wr_state *wr_mas)
>  int mas_store_gfp(struct ma_state *mas, void *entry, gfp_t gfp)
>  {
>  	MA_WR_STATE(wr_mas, mas, entry);
> +	int request;
>  
>  	mas_wr_store_setup(&wr_mas);
> -	trace_ma_write(__func__, mas, 0, entry);
> -retry:
> +	wr_mas.content = mas_start(mas);
> +
> +	request = mas_prealloc_calc(&wr_mas);
> +	if (!request)
> +		goto store_entry;
> +
> +	mas_node_count_gfp(mas, request, gfp);
> +	if (unlikely(mas_is_err(mas))) {
> +		mas_set_alloc_req(mas, 0);
> +		mas_destroy(mas);
> +		mas_reset(mas);
> +		return xa_err(mas->node);
> +	}
> +	mas->mas_flags |= MA_STATE_PREALLOC;
> +
> +store_entry:
>  	mas_wr_store_entry(&wr_mas);
>  	if (unlikely(mas_nomem(mas, gfp)))
> -		goto retry;
> +		goto store_entry;
>  
>  	if (unlikely(mas_is_err(mas)))
>  		return xa_err(mas->node);
>  
> +	trace_ma_write(__func__, mas, 0, entry);
>  	return 0;
>  }
>  EXPORT_SYMBOL_GPL(mas_store_gfp);
> -- 
> 2.41.0
> 

Re: [PATCH 2/3] maple_tree: use preallocations in mas_store_gfp()

[kernel test robot]

Hello,

kernel test robot noticed "BUG:sleeping_function_called_from_invalid_context_at_include/linux/sched/mm.h" on:

commit: 9116baa49536116f013d691d2178c520959f46c2 ("[PATCH 2/3] maple_tree: use preallocations in mas_store_gfp()")
url: https://github.com/intel-lab-lkp/linux/commits/Sidhartha-Kumar/maple_tree-introduce-mas_prealloc_calc/20231010-041859
base: https://git.kernel.org/cgit/linux/kernel/git/akpm/mm.git mm-everything
patch link: https://lore.kernel.org/all/20231009201639.920512-3-sidhartha.kumar@oracle.com/
patch subject: [PATCH 2/3] maple_tree: use preallocations in mas_store_gfp()

in testcase: boot

compiler: gcc-11
test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G

(please refer to attached dmesg/kmsg for entire log/backtrace)


+------------------------------------------------------------------------------------+------------+------------+
|                                                                                    | 9cbebad6db | 9116baa495 |
+------------------------------------------------------------------------------------+------------+------------+
| BUG:sleeping_function_called_from_invalid_context_at_include/linux/sched/mm.h      | 0          | 7          |
| WARNING:suspicious_RCU_usage                                                       | 0          | 7          |
| include/linux/rcupdate.h:#Illegal_context_switch_in_RCU_read-side_critical_section | 0          | 7          |
+------------------------------------------------------------------------------------+------------+------------+


If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202310251706.6e6f6c4a-oliver.sang@intel.com


[   12.322393][    T1] BUG: sleeping function called from invalid context at include/linux/sched/mm.h:306
[   12.324008][    T1] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper
[   12.325486][    T1] preempt_count: 1, expected: 0
[   12.326345][    T1] 1 lock held by swapper/1:
[ 12.327164][ T1] #0: c2b52570 (&mt->ma_lock){+.+.}-{2:2}, at: check_root_expand+0x46/0xac0 
[   12.328850][    T1] CPU: 0 PID: 1 Comm: swapper Tainted: G                T  6.6.0-rc4-00400-g9116baa49536 #1
[   12.329034][    T1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[   12.329034][    T1] Call Trace:
[ 12.329034][ T1] dump_stack_lvl (lib/dump_stack.c:107 (discriminator 1)) 
[ 12.329034][ T1] dump_stack (lib/dump_stack.c:114) 
[ 12.329034][ T1] __might_resched (kernel/sched/core.c:10188) 
[ 12.329034][ T1] __might_sleep (kernel/sched/core.c:10117 (discriminator 17)) 
[ 12.329034][ T1] kmem_cache_alloc (include/linux/sched/mm.h:306 mm/slab.h:705 mm/slub.c:3460 mm/slub.c:3486 mm/slub.c:3493 mm/slub.c:3502) 
[ 12.329034][ T1] ? mas_alloc_nodes (lib/maple_tree.c:160 lib/maple_tree.c:1265) 
[ 12.329034][ T1] mas_alloc_nodes (lib/maple_tree.c:160 lib/maple_tree.c:1265) 
[ 12.329034][ T1] mas_node_count_gfp (lib/maple_tree.c:1347) 
[ 12.329034][ T1] mas_store_gfp (lib/maple_tree.c:256 lib/maple_tree.c:5491) 
[ 12.329034][ T1] ? check_empty_area_fill+0x3d0/0x3d0 
[ 12.329034][ T1] check_root_expand+0x162/0xac0 
[ 12.329034][ T1] maple_tree_seed (lib/test_maple_tree.c:3577) 
[ 12.329034][ T1] ? check_gap_combining+0xdf8/0xdf8 
[ 12.329034][ T1] do_one_initcall (init/main.c:1232) 
[ 12.329034][ T1] do_initcalls (init/main.c:1293 init/main.c:1310) 
[ 12.329034][ T1] kernel_init_freeable (init/main.c:1551) 
[ 12.329034][ T1] ? rest_init (init/main.c:1429) 
[ 12.329034][ T1] kernel_init (init/main.c:1439) 
[ 12.329034][ T1] ret_from_fork (arch/x86/kernel/process.c:153) 
[ 12.329034][ T1] ? rest_init (init/main.c:1429) 
[ 12.329034][ T1] ret_from_fork_asm (arch/x86/entry/entry_32.S:741) 
[ 12.329034][ T1] entry_INT80_32 (arch/x86/entry/entry_32.S:944) 
[   12.353802][    T1]
[   12.354345][    T1] =============================
[   12.355188][    T1] WARNING: suspicious RCU usage
[   12.356056][    T1] 6.6.0-rc4-00400-g9116baa49536 #1 Tainted: G        W       T
[   12.357413][    T1] -----------------------------
[   12.358272][    T1] include/linux/rcupdate.h:375 Illegal context switch in RCU read-side critical section!
[   12.359905][    T1]
[   12.359905][    T1] other info that might help us debug this:
[   12.359905][    T1]
[   12.361711][    T1]
[   12.361711][    T1] rcu_scheduler_active = 2, debug_locks = 1
[   12.363058][    T1] 2 locks held by swapper/1:
[ 12.363877][ T1] #0: c2ad5938 (rcu_read_lock){....}-{1:2}, at: check_mas_store_gfp+0xa9/0x1b0 
[ 12.365646][ T1] #1: c3965e84 (&mt->ma_lock){+.+.}-{2:2}, at: check_mas_store_gfp+0x104/0x1b0 
[   12.367338][    T1]
[   12.367338][    T1] stack backtrace:
[   12.368430][    T1] CPU: 0 PID: 1 Comm: swapper Tainted: G        W       T  6.6.0-rc4-00400-g9116baa49536 #1
[   12.369129][    T1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[   12.369129][    T1] Call Trace:
[ 12.369129][ T1] dump_stack_lvl (lib/dump_stack.c:107 (discriminator 1)) 
[ 12.369129][ T1] dump_stack (lib/dump_stack.c:114) 
[ 12.369129][ T1] lockdep_rcu_suspicious (kernel/locking/lockdep.c:6713) 
[ 12.369129][ T1] __might_resched (include/linux/rcupdate.h:375 kernel/sched/core.c:10149) 
[ 12.369129][ T1] __might_sleep (kernel/sched/core.c:10117 (discriminator 17)) 
[ 12.369129][ T1] kmem_cache_alloc (include/linux/sched/mm.h:306 mm/slab.h:705 mm/slub.c:3460 mm/slub.c:3486 mm/slub.c:3493 mm/slub.c:3502) 
[ 12.369129][ T1] ? mas_alloc_nodes (lib/maple_tree.c:160 lib/maple_tree.c:1265) 
[ 12.369129][ T1] mas_alloc_nodes (lib/maple_tree.c:160 lib/maple_tree.c:1265) 
[ 12.369129][ T1] mas_node_count_gfp (lib/maple_tree.c:1347) 
[ 12.369129][ T1] mas_store_gfp (lib/maple_tree.c:256 lib/maple_tree.c:5491) 
[ 12.369129][ T1] check_mas_store_gfp+0x14b/0x1b0 
[ 12.369129][ T1] maple_tree_seed (lib/test_maple_tree.c:3646) 
[ 12.369129][ T1] ? check_gap_combining+0xdf8/0xdf8 
[ 12.369129][ T1] do_one_initcall (init/main.c:1232) 
[ 12.369129][ T1] do_initcalls (init/main.c:1293 init/main.c:1310) 
[ 12.369129][ T1] kernel_init_freeable (init/main.c:1551) 
[ 12.369129][ T1] ? rest_init (init/main.c:1429) 
[ 12.369129][ T1] kernel_init (init/main.c:1439) 
[ 12.369129][ T1] ret_from_fork (arch/x86/kernel/process.c:153) 
[ 12.369129][ T1] ? rest_init (init/main.c:1429) 
[ 12.369129][ T1] ret_from_fork_asm (arch/x86/entry/entry_32.S:741) 
[ 12.369129][ T1] entry_INT80_32 (arch/x86/entry/entry_32.S:944) 
[   15.220029][   T34] torture_spin_lock_write_delay: delay = 25 jiffies.
[   16.033920][   T35] torture_spin_lock_write_delay: delay = 25 jiffies.
[   17.655206][   T35] torture_spin_lock_write_delay: delay = 25 jiffies.
[   19.245918][   T35] torture_spin_lock_write_delay: delay = 25 jiffies.
[   36.522020][   T34] torture_spin_lock_write_delay: delay = 25 jiffies.
[   37.994914][   T34] torture_spin_lock_write_delay: delay = 25 jiffies.
[   38.766533][   T35] torture_spin_lock_write_delay: delay = 25 jiffies.
[   41.775652][   T34] torture_spin_lock_write_delay: delay = 25 jiffies.
[   43.236341][   T35] torture_spin_lock_write_delay: delay = 24 jiffies.
[   44.106914][   T34] torture_spin_lock_write_delay: delay = 25 jiffies.
[   46.776934][   T34] torture_spin_lock_write_delay: delay = 25 jiffies.
[   47.165604][   T35] torture_spin_lock_write_delay: delay = 25 jiffies.
[   49.209209][   T34] torture_spin_lock_write_delay: delay = 25 jiffies.
[   50.316931][   T35] torture_spin_lock_write_delay: delay = 25 jiffies.
[   51.511048][   T34] torture_spin_lock_write_delay: delay = 25 jiffies.
[   54.564928][   T35] torture_spin_lock_write_delay: delay = 25 jiffies.
[   59.372367][    T1] BUG: sleeping function called from invalid context at include/linux/sched/mm.h:306
[   59.374045][    T1] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper
[   59.375483][    T1] preempt_count: 1, expected: 0
[   59.376310][    T1] 1 lock held by swapper/1:
[ 59.377090][ T1] #0: c2b52570 (&mt->ma_lock){+.+.}-{2:2}, at: check_empty_area_fill+0xe5/0x3d0 
[   59.378744][    T1] CPU: 0 PID: 1 Comm: swapper Tainted: G        W       T  6.6.0-rc4-00400-g9116baa49536 #1
[   59.380409][    T1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[   59.381080][    T1] Call Trace:
[ 59.381080][ T1] dump_stack_lvl (lib/dump_stack.c:107 (discriminator 1)) 
[ 59.381080][ T1] dump_stack (lib/dump_stack.c:114) 
[ 59.381080][ T1] __might_resched (kernel/sched/core.c:10188) 
[ 59.381080][ T1] __might_sleep (kernel/sched/core.c:10117 (discriminator 17)) 
[ 59.381080][ T1] kmem_cache_alloc (include/linux/sched/mm.h:306 mm/slab.h:705 mm/slub.c:3460 mm/slub.c:3486 mm/slub.c:3493 mm/slub.c:3502) 
[ 59.381080][ T1] ? mas_alloc_nodes (lib/maple_tree.c:160 lib/maple_tree.c:1265) 
[ 59.381080][ T1] mas_alloc_nodes (lib/maple_tree.c:160 lib/maple_tree.c:1265) 
[ 59.381080][ T1] mas_node_count_gfp (lib/maple_tree.c:1347) 
[ 59.381080][ T1] mas_store_gfp (lib/maple_tree.c:256 lib/maple_tree.c:5491) 
[ 59.381080][ T1] check_empty_area_fill+0xab/0x3d0 
[ 59.381080][ T1] maple_tree_seed (lib/test_maple_tree.c:3837) 
[ 59.381080][ T1] ? check_gap_combining+0xdf8/0xdf8 
[ 59.381080][ T1] do_one_initcall (init/main.c:1232) 
[ 59.381080][ T1] do_initcalls (init/main.c:1293 init/main.c:1310) 
[ 59.381080][ T1] kernel_init_freeable (init/main.c:1551) 
[ 59.381080][ T1] ? rest_init (init/main.c:1429) 
[ 59.381080][ T1] kernel_init (init/main.c:1439) 
[ 59.381080][ T1] ret_from_fork (arch/x86/kernel/process.c:153) 
[ 59.381080][ T1] ? rest_init (init/main.c:1429) 
[ 59.381080][ T1] ret_from_fork_asm (arch/x86/entry/entry_32.S:741) 
[ 59.381080][ T1] entry_INT80_32 (arch/x86/entry/entry_32.S:944) 
[   59.571154][    T1] maple_tree: 3807933 of 3807933 tests passed
[   59.572831][    T1] test_memcat_p: test passed
[   59.590510][    T1] test_meminit: all 11 tests in test_pages passed
[   59.621976][    T1] test_meminit: all 40 tests in test_kvmalloc passed
[   60.207905][    T1] test_meminit: all 70 tests in test_kmemcache passed
[   60.217750][    T1] test_meminit: all 10 tests in test_rcu_persistent passed
[   60.219088][    T1] test_meminit: all 131 tests passed!
[   60.220126][    T1] ref_tracker: reference already released.
[   60.220912][    T1] ref_tracker: allocated in:



The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20231025/202310251706.6e6f6c4a-oliver.sang@intel.com



-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 2/3] maple_tree: use preallocations in mas_store_gfp()

[Liam R. Howlett]

... Dropping direct Cc's in attempt to avoid even more noise.

* kernel test robot <oliver.sang@intel.com> [231025 05:52]:
> 
> 
> Hello,
> 
> kernel test robot noticed "BUG:sleeping_function_called_from_invalid_context_at_include/linux/sched/mm.h" on:
...

This patch set is being revised and discussed on how to make it a more
complete solution.

In the mean time, is there any way to stop the bot from emailing
everyone and burning more power?

Thank you,
Liam

[PATCH 3/3] maple_tree: use preallocations in mas_erase()

[Sidhartha Kumar]

Preallocate the number of needed nodes before mas_wr_store_entry().

Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
---
 lib/maple_tree.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 25ae66e585f4..ef8d4b6b4456 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -6191,6 +6191,7 @@ void *mas_erase(struct ma_state *mas)
 {
 	void *entry;
 	MA_WR_STATE(wr_mas, mas, NULL);
+	int request;
 
 	if (mas_is_none(mas) || mas_is_paused(mas))
 		mas->node = MAS_START;
@@ -6200,14 +6201,30 @@ void *mas_erase(struct ma_state *mas)
 	if (!entry)
 		return NULL;
 
-write_retry:
 	/* Must reset to ensure spanning writes of last slot are detected */
 	mas_reset(mas);
 	mas_wr_store_setup(&wr_mas);
+	wr_mas.content = mas_start(mas);
+
+	request = mas_prealloc_calc(&wr_mas);
+	if (!request)
+		goto store_entry;
+
+	mas_node_count_gfp(mas, request, GFP_KERNEL);
+	if (unlikely(mas_is_err(mas))) {
+		mas_set_alloc_req(mas, 0);
+		mas_destroy(mas);
+		mas_reset(mas);
+		return NULL;
+	}
+	mas->mas_flags |= MA_STATE_PREALLOC;
+
+store_entry:
 	mas_wr_store_entry(&wr_mas);
 	if (mas_nomem(mas, GFP_KERNEL))
-		goto write_retry;
+		goto store_entry;
 
+	trace_ma_write(__func__, mas, 0, entry);
 	return entry;
 }
 EXPORT_SYMBOL_GPL(mas_erase);
-- 
2.41.0