| Message ID | 20231213205058.386589-1-sidhartha.kumar@oracle.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [V2] maple_tree: do not preallocate nodes for slot stores | expand |
On 12/13/23 12:50 PM, Sidhartha Kumar wrote: > mas_preallocate() defaults to requesting 1 node for preallocation and then > ,depending on the type of store, will update the request variable. There > isn't a check for a slot store type, so slot stores are preallocating the > default 1 node. Slot stores do not require any additional nodes, so add a > check for the slot store case that will bypass node_count_gfp(). Update > the tests to reflect that slot stores do not require allocations. > > User visible effects of this bug include increased memory usage from the > unneeded node that was allocated. > > Fixes: 0b8bb544b1a7 ("maple_tree: update mas_preallocate() testing") > Cc: <stable@vger.kernel.org> # 6.6+ > Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> > --- > v1->v2: > fix coding style per Matthew and Andrew > use wr_mas->node_end to fix build error > When this is merged to mm-unstable could the following fixlet be applied to be compatible with Liam's series[1]: [1]: https://lore.kernel.org/all/20231101171629.3612299-5-Liam.Howlett@oracle.com/T/#mc0e5000f6de822182bf7579c230030c5ec4ec1a7 diff --git a/lib/maple_tree.c b/lib/maple_tree.c index 1130803b9d3f7..c9a970ea20dd5 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -5477,7 +5477,7 @@ int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp) node_size = mas_wr_new_end(&wr_mas); /* Slot store, does not require additional nodes */ - if (node_size == wr_mas.node_end) { + if (node_size == mas->end) { /* reuse node */ if (!mt_in_rcu(mas->tree)) return 0; > > lib/maple_tree.c | 11 +++++++++++ > tools/testing/radix-tree/maple.c | 2 +- > 2 files changed, 12 insertions(+), 1 deletion(-) > > diff --git a/lib/maple_tree.c b/lib/maple_tree.c > index bb24d84a4922f..684689457d77f 100644 > --- a/lib/maple_tree.c > +++ b/lib/maple_tree.c > @@ -5501,6 +5501,17 @@ int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp) > > mas_wr_end_piv(&wr_mas); > node_size = mas_wr_new_end(&wr_mas); > + > + /* Slot store, does not require additional nodes */ > + if (node_size == wr_mas.node_end) { > + /* reuse node */ > + if (!mt_in_rcu(mas->tree)) > + return 0; > + /* shifting boundary */ > + if (wr_mas.offset_end - mas->offset == 1) > + return 0; > + } > + > if (node_size >= mt_slots[wr_mas.type]) { > /* Split, worst case for now. */ > request = 1 + mas_mt_height(mas) * 2; > diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c > index e5da1cad70baf..76a8990bb14e8 100644 > --- a/tools/testing/radix-tree/maple.c > +++ b/tools/testing/radix-tree/maple.c > @@ -35538,7 +35538,7 @@ static noinline void __init check_prealloc(struct maple_tree *mt) > MT_BUG_ON(mt, mas_preallocate(&mas, ptr, GFP_KERNEL) != 0); > allocated = mas_allocated(&mas); > height = mas_mt_height(&mas); > - MT_BUG_ON(mt, allocated != 1); > + MT_BUG_ON(mt, allocated != 0); > mas_store_prealloc(&mas, ptr); > MT_BUG_ON(mt, mas_allocated(&mas) != 0); >
On Wed, 13 Dec 2023 13:03:29 -0800 Sidhartha Kumar <sidhartha.kumar@oracle.com> wrote: > On 12/13/23 12:50 PM, Sidhartha Kumar wrote: > > mas_preallocate() defaults to requesting 1 node for preallocation and then > > ,depending on the type of store, will update the request variable. There > > isn't a check for a slot store type, so slot stores are preallocating the > > default 1 node. Slot stores do not require any additional nodes, so add a > > check for the slot store case that will bypass node_count_gfp(). Update > > the tests to reflect that slot stores do not require allocations. > > > > User visible effects of this bug include increased memory usage from the > > unneeded node that was allocated. > > > > Fixes: 0b8bb544b1a7 ("maple_tree: update mas_preallocate() testing") > > Cc: <stable@vger.kernel.org> # 6.6+ > > Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> > > --- > > v1->v2: > > fix coding style per Matthew and Andrew > > use wr_mas->node_end to fix build error > > > > When this is merged to mm-unstable could the following fixlet be applied to be > compatible with Liam's series[1]: > Yup, already on it. Liam's series is now in mm-stable so for now I'll leave a bisection hole. Maybe I'll fold it later if an mm-stable rebase/rebuild is needed, From: Andrew Morton <akpm@linux-foundation.org> Subject: lib/maple_tree.c: fix build error due to hotfix alteration Date: Wed Dec 13 12:59:49 PM PST 2023 Commit 0de56e38b307 ("maple_tree: use maple state end for write operations") was broken by a later patch "maple_tree: do not preallocate nodes for slot stores". But the later patch was scheduled ahead of 0de56e38b307, for 6.7-rc. This fixlet undoes the damage. Fixes: 0de56e38b307 ("maple_tree: use maple state end for write operations") Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> --- lib/maple_tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/lib/maple_tree.c~lib-maple_treec-fix-build-error-due-to-hotfix-alteration +++ a/lib/maple_tree.c @@ -5477,7 +5477,7 @@ int mas_preallocate(struct ma_state *mas node_size = mas_wr_new_end(&wr_mas); /* Slot store, does not require additional nodes */ - if (node_size == wr_mas.node_end) { + if (node_size == mas->end) { /* reuse node */ if (!mt_in_rcu(mas->tree)) return 0;
diff --git a/lib/maple_tree.c b/lib/maple_tree.c index bb24d84a4922f..684689457d77f 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -5501,6 +5501,17 @@ int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp) mas_wr_end_piv(&wr_mas); node_size = mas_wr_new_end(&wr_mas); + + /* Slot store, does not require additional nodes */ + if (node_size == wr_mas.node_end) { + /* reuse node */ + if (!mt_in_rcu(mas->tree)) + return 0; + /* shifting boundary */ + if (wr_mas.offset_end - mas->offset == 1) + return 0; + } + if (node_size >= mt_slots[wr_mas.type]) { /* Split, worst case for now. */ request = 1 + mas_mt_height(mas) * 2; diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c index e5da1cad70baf..76a8990bb14e8 100644 --- a/tools/testing/radix-tree/maple.c +++ b/tools/testing/radix-tree/maple.c @@ -35538,7 +35538,7 @@ static noinline void __init check_prealloc(struct maple_tree *mt) MT_BUG_ON(mt, mas_preallocate(&mas, ptr, GFP_KERNEL) != 0); allocated = mas_allocated(&mas); height = mas_mt_height(&mas); - MT_BUG_ON(mt, allocated != 1); + MT_BUG_ON(mt, allocated != 0); mas_store_prealloc(&mas, ptr); MT_BUG_ON(mt, mas_allocated(&mas) != 0);
mas_preallocate() defaults to requesting 1 node for preallocation and then ,depending on the type of store, will update the request variable. There isn't a check for a slot store type, so slot stores are preallocating the default 1 node. Slot stores do not require any additional nodes, so add a check for the slot store case that will bypass node_count_gfp(). Update the tests to reflect that slot stores do not require allocations. User visible effects of this bug include increased memory usage from the unneeded node that was allocated. Fixes: 0b8bb544b1a7 ("maple_tree: update mas_preallocate() testing") Cc: <stable@vger.kernel.org> # 6.6+ Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> --- v1->v2: fix coding style per Matthew and Andrew use wr_mas->node_end to fix build error lib/maple_tree.c | 11 +++++++++++ tools/testing/radix-tree/maple.c | 2 +- 2 files changed, 12 insertions(+), 1 deletion(-)