The "memramp() shrinking" scenario no longer applies, so let's remove
that now-unnecessary handling.
Signed-off-by: David Hildenbrand <david@redhat.com>
---
arch/x86/mm/pat/memtype_interval.c | 44 ++++--------------------------
1 file changed, 6 insertions(+), 38 deletions(-)
diff --git a/arch/x86/mm/pat/memtype_interval.c b/arch/x86/mm/pat/memtype_interval.c
index 645613d59942a..9d03f0dbc4715 100644
--- a/arch/x86/mm/pat/memtype_interval.c
+++ b/arch/x86/mm/pat/memtype_interval.c
@@ -49,26 +49,15 @@ INTERVAL_TREE_DEFINE(struct memtype, rb, u64, subtree_max_end,
static struct rb_root_cached memtype_rbroot = RB_ROOT_CACHED;
-enum {
- MEMTYPE_EXACT_MATCH = 0,
- MEMTYPE_END_MATCH = 1
-};
-
-static struct memtype *memtype_match(u64 start, u64 end, int match_type)
+static struct memtype *memtype_match(u64 start, u64 end)
{
struct memtype *entry_match;
entry_match = interval_iter_first(&memtype_rbroot, start, end-1);
while (entry_match != NULL && entry_match->start < end) {
- if ((match_type == MEMTYPE_EXACT_MATCH) &&
- (entry_match->start == start) && (entry_match->end == end))
- return entry_match;
-
- if ((match_type == MEMTYPE_END_MATCH) &&
- (entry_match->start < start) && (entry_match->end == end))
+ if (entry_match->start == start && entry_match->end == end)
return entry_match;
-
entry_match = interval_iter_next(entry_match, start, end-1);
}
@@ -132,32 +121,11 @@ struct memtype *memtype_erase(u64 start, u64 end)
{
struct memtype *entry_old;
- /*
- * Since the memtype_rbroot tree allows overlapping ranges,
- * memtype_erase() checks with EXACT_MATCH first, i.e. free
- * a whole node for the munmap case. If no such entry is found,
- * it then checks with END_MATCH, i.e. shrink the size of a node
- * from the end for the mremap case.
- */
- entry_old = memtype_match(start, end, MEMTYPE_EXACT_MATCH);
- if (!entry_old) {
- entry_old = memtype_match(start, end, MEMTYPE_END_MATCH);
- if (!entry_old)
- return ERR_PTR(-EINVAL);
- }
-
- if (entry_old->start == start) {
- /* munmap: erase this node */
- interval_remove(entry_old, &memtype_rbroot);
- } else {
- /* mremap: update the end value of this node */
- interval_remove(entry_old, &memtype_rbroot);
- entry_old->end = start;
- interval_insert(entry_old, &memtype_rbroot);
-
- return NULL;
- }
+ entry_old = memtype_match(start, end);
+ if (!entry_old)
+ return ERR_PTR(-EINVAL);
+ interval_remove(entry_old, &memtype_rbroot);
return entry_old;
}
--
2.49.0On Fri, Apr 25, 2025 at 10:17:13AM +0200, David Hildenbrand wrote:
> The "memramp() shrinking" scenario no longer applies, so let's remove
> that now-unnecessary handling.
I wonder if we could remove even more of the code here given the
simplifications here? But not a big deal.
>
> Signed-off-by: David Hildenbrand <david@redhat.com>
More lovely removal...
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> ---
> arch/x86/mm/pat/memtype_interval.c | 44 ++++--------------------------
> 1 file changed, 6 insertions(+), 38 deletions(-)
>
> diff --git a/arch/x86/mm/pat/memtype_interval.c b/arch/x86/mm/pat/memtype_interval.c
> index 645613d59942a..9d03f0dbc4715 100644
> --- a/arch/x86/mm/pat/memtype_interval.c
> +++ b/arch/x86/mm/pat/memtype_interval.c
> @@ -49,26 +49,15 @@ INTERVAL_TREE_DEFINE(struct memtype, rb, u64, subtree_max_end,
>
> static struct rb_root_cached memtype_rbroot = RB_ROOT_CACHED;
>
> -enum {
> - MEMTYPE_EXACT_MATCH = 0,
> - MEMTYPE_END_MATCH = 1
> -};
> -
> -static struct memtype *memtype_match(u64 start, u64 end, int match_type)
> +static struct memtype *memtype_match(u64 start, u64 end)
> {
> struct memtype *entry_match;
>
> entry_match = interval_iter_first(&memtype_rbroot, start, end-1);
>
> while (entry_match != NULL && entry_match->start < end) {
> - if ((match_type == MEMTYPE_EXACT_MATCH) &&
> - (entry_match->start == start) && (entry_match->end == end))
> - return entry_match;
> -
> - if ((match_type == MEMTYPE_END_MATCH) &&
> - (entry_match->start < start) && (entry_match->end == end))
> + if (entry_match->start == start && entry_match->end == end)
> return entry_match;
> -
> entry_match = interval_iter_next(entry_match, start, end-1);
> }
>
> @@ -132,32 +121,11 @@ struct memtype *memtype_erase(u64 start, u64 end)
> {
> struct memtype *entry_old;
>
> - /*
> - * Since the memtype_rbroot tree allows overlapping ranges,
> - * memtype_erase() checks with EXACT_MATCH first, i.e. free
> - * a whole node for the munmap case. If no such entry is found,
> - * it then checks with END_MATCH, i.e. shrink the size of a node
> - * from the end for the mremap case.
> - */
> - entry_old = memtype_match(start, end, MEMTYPE_EXACT_MATCH);
> - if (!entry_old) {
> - entry_old = memtype_match(start, end, MEMTYPE_END_MATCH);
> - if (!entry_old)
> - return ERR_PTR(-EINVAL);
> - }
> -
> - if (entry_old->start == start) {
> - /* munmap: erase this node */
> - interval_remove(entry_old, &memtype_rbroot);
> - } else {
> - /* mremap: update the end value of this node */
> - interval_remove(entry_old, &memtype_rbroot);
> - entry_old->end = start;
> - interval_insert(entry_old, &memtype_rbroot);
> -
> - return NULL;
> - }
> + entry_old = memtype_match(start, end);
> + if (!entry_old)
> + return ERR_PTR(-EINVAL);
>
> + interval_remove(entry_old, &memtype_rbroot);
> return entry_old;
> }
>
> --
> 2.49.0
>
On 28.04.25 22:23, Lorenzo Stoakes wrote:
> On Fri, Apr 25, 2025 at 10:17:13AM +0200, David Hildenbrand wrote:
>> The "memramp() shrinking" scenario no longer applies, so let's remove
>> that now-unnecessary handling.
>
> I wonder if we could remove even more of the code here given the
> simplifications here? But not a big deal.
It might make sense to inline memtype_match().
diff --git a/arch/x86/mm/pat/memtype_interval.c b/arch/x86/mm/pat/memtype_interval.c
index 9d03f0dbc4715..e5844ed1311ed 100644
--- a/arch/x86/mm/pat/memtype_interval.c
+++ b/arch/x86/mm/pat/memtype_interval.c
@@ -49,21 +49,6 @@ INTERVAL_TREE_DEFINE(struct memtype, rb, u64, subtree_max_end,
static struct rb_root_cached memtype_rbroot = RB_ROOT_CACHED;
-static struct memtype *memtype_match(u64 start, u64 end)
-{
- struct memtype *entry_match;
-
- entry_match = interval_iter_first(&memtype_rbroot, start, end-1);
-
- while (entry_match != NULL && entry_match->start < end) {
- if (entry_match->start == start && entry_match->end == end)
- return entry_match;
- entry_match = interval_iter_next(entry_match, start, end-1);
- }
-
- return NULL; /* Returns NULL if there is no match */
-}
-
static int memtype_check_conflict(u64 start, u64 end,
enum page_cache_mode reqtype,
enum page_cache_mode *newtype)
@@ -119,14 +104,16 @@ int memtype_check_insert(struct memtype *entry_new, enum page_cache_mode *ret_ty
struct memtype *memtype_erase(u64 start, u64 end)
{
- struct memtype *entry_old;
-
- entry_old = memtype_match(start, end);
- if (!entry_old)
- return ERR_PTR(-EINVAL);
-
- interval_remove(entry_old, &memtype_rbroot);
- return entry_old;
+ struct memtype *entry = interval_iter_first(&memtype_rbroot, start, end - 1);
+
+ while (entry && entry->start < end) {
+ if (entry->start == start && entry->end == end) {
+ interval_remove(entry, &memtype_rbroot);
+ return entry;
+ }
+ entry = interval_iter_next(entry, start, end - 1);
+ }
+ return ERR_PTR(-EINVAL);
}
struct memtype *memtype_lookup(u64 addr)
Thanks for all the review!
--
Cheers,
David / dhildenb
On Mon, May 05, 2025 at 02:10:53PM +0200, David Hildenbrand wrote:
> On 28.04.25 22:23, Lorenzo Stoakes wrote:
> > On Fri, Apr 25, 2025 at 10:17:13AM +0200, David Hildenbrand wrote:
> > > The "memramp() shrinking" scenario no longer applies, so let's remove
> > > that now-unnecessary handling.
> >
> > I wonder if we could remove even more of the code here given the
> > simplifications here? But not a big deal.
>
> It might make sense to inline memtype_match().
>
> diff --git a/arch/x86/mm/pat/memtype_interval.c b/arch/x86/mm/pat/memtype_interval.c
> index 9d03f0dbc4715..e5844ed1311ed 100644
> --- a/arch/x86/mm/pat/memtype_interval.c
> +++ b/arch/x86/mm/pat/memtype_interval.c
> @@ -49,21 +49,6 @@ INTERVAL_TREE_DEFINE(struct memtype, rb, u64, subtree_max_end,
> static struct rb_root_cached memtype_rbroot = RB_ROOT_CACHED;
> -static struct memtype *memtype_match(u64 start, u64 end)
> -{
> - struct memtype *entry_match;
> -
> - entry_match = interval_iter_first(&memtype_rbroot, start, end-1);
> -
> - while (entry_match != NULL && entry_match->start < end) {
> - if (entry_match->start == start && entry_match->end == end)
> - return entry_match;
> - entry_match = interval_iter_next(entry_match, start, end-1);
> - }
> -
> - return NULL; /* Returns NULL if there is no match */
> -}
> -
> static int memtype_check_conflict(u64 start, u64 end,
> enum page_cache_mode reqtype,
> enum page_cache_mode *newtype)
> @@ -119,14 +104,16 @@ int memtype_check_insert(struct memtype *entry_new, enum page_cache_mode *ret_ty
> struct memtype *memtype_erase(u64 start, u64 end)
> {
> - struct memtype *entry_old;
> -
> - entry_old = memtype_match(start, end);
> - if (!entry_old)
> - return ERR_PTR(-EINVAL);
> -
> - interval_remove(entry_old, &memtype_rbroot);
> - return entry_old;
> + struct memtype *entry = interval_iter_first(&memtype_rbroot, start, end - 1);
> +
> + while (entry && entry->start < end) {
> + if (entry->start == start && entry->end == end) {
> + interval_remove(entry, &memtype_rbroot);
> + return entry;
> + }
> + entry = interval_iter_next(entry, start, end - 1);
> + }
> + return ERR_PTR(-EINVAL);
> }
> struct memtype *memtype_lookup(u64 addr)
>
>
> Thanks for all the review!
You're welcome :)
I _think_ I'm all caught up on my side of this review, ping me if there's
anything more you need from me.
>
> --
> Cheers,
>
> David / dhildenb
>
Cheers, Lorenzo
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