diff mbox series

[v3,net-next,12/14] af_unix: Detect dead SCC.

Message ID 20240223214003.17369-13-kuniyu@amazon.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series af_unix: Rework GC. | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 942 this patch: 942
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 5 of 5 maintainers
netdev/build_clang success Errors and warnings before: 958 this patch: 958
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 959 this patch: 959
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 67 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-02-27--03-00 (tests: 1456)

Commit Message

Kuniyuki Iwashima Feb. 23, 2024, 9:40 p.m. UTC
When iterating SCC, we call unix_vertex_dead() for each vertex
to check if the vertex is close()d and has no bridge to another
SCC.

If both conditions are true for every vertex in SCC, we can
execute garbage collection for all skb in the SCC.

The actual garbage collection is done in the following patch,
replacing the old implementation.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 net/unix/garbage.c | 37 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

Comments

Paolo Abeni Feb. 27, 2024, 11:25 a.m. UTC | #1
On Fri, 2024-02-23 at 13:40 -0800, Kuniyuki Iwashima wrote:
> When iterating SCC, we call unix_vertex_dead() for each vertex
> to check if the vertex is close()d and has no bridge to another
> SCC.
> 
> If both conditions are true for every vertex in SCC, we can
> execute garbage collection for all skb in the SCC.
> 
> The actual garbage collection is done in the following patch,
> replacing the old implementation.
> 
> Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
> ---
>  net/unix/garbage.c | 37 ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 36 insertions(+), 1 deletion(-)
> 
> diff --git a/net/unix/garbage.c b/net/unix/garbage.c
> index 0eb1610c96d7..060e81be3614 100644
> --- a/net/unix/garbage.c
> +++ b/net/unix/garbage.c
> @@ -288,6 +288,32 @@ void unix_destroy_fpl(struct scm_fp_list *fpl)
>  	unix_free_vertices(fpl);
>  }
>  
> +static bool unix_vertex_dead(struct unix_vertex *vertex)
> +{
> +	struct unix_edge *edge;
> +	struct unix_sock *u;
> +	long total_ref;
> +
> +	list_for_each_entry(edge, &vertex->edges, vertex_entry) {
> +		struct unix_vertex *next_vertex = unix_edge_successor(edge);
> +
> +		if (!next_vertex)
> +			return false;
> +
> +		if (next_vertex->scc_index != vertex->scc_index)
> +			return false;
> +	}
> +
> +	edge = list_first_entry(&vertex->edges, typeof(*edge), vertex_entry);
> +	u = edge->predecessor;
> +	total_ref = file_count(u->sk.sk_socket->file);
> +
> +	if (total_ref != vertex->out_degree)
> +		return false;
> +
> +	return true;
> +}
> +
>  static bool unix_scc_cyclic(struct list_head *scc)
>  {
>  	struct unix_vertex *vertex;
> @@ -350,6 +376,7 @@ static void __unix_walk_scc(struct unix_vertex *vertex)
>  
>  	if (vertex->index == vertex->scc_index) {
>  		struct list_head scc;
> +		bool dead = true;

Very minor nit: the above variable 'sounds' alike referring to the
current vertex, while instead it tracks a global status, what about
'all_dead' or 'gc_all'?

Thanks,

Paolo
Kuniyuki Iwashima Feb. 28, 2024, 3:14 a.m. UTC | #2
From: Paolo Abeni <pabeni@redhat.com>
Date: Tue, 27 Feb 2024 12:25:56 +0100
> On Fri, 2024-02-23 at 13:40 -0800, Kuniyuki Iwashima wrote:
> > When iterating SCC, we call unix_vertex_dead() for each vertex
> > to check if the vertex is close()d and has no bridge to another
> > SCC.
> > 
> > If both conditions are true for every vertex in SCC, we can
> > execute garbage collection for all skb in the SCC.
> > 
> > The actual garbage collection is done in the following patch,
> > replacing the old implementation.
> > 
> > Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
> > ---
> >  net/unix/garbage.c | 37 ++++++++++++++++++++++++++++++++++++-
> >  1 file changed, 36 insertions(+), 1 deletion(-)
> > 
> > diff --git a/net/unix/garbage.c b/net/unix/garbage.c
> > index 0eb1610c96d7..060e81be3614 100644
> > --- a/net/unix/garbage.c
> > +++ b/net/unix/garbage.c
> > @@ -288,6 +288,32 @@ void unix_destroy_fpl(struct scm_fp_list *fpl)
> >  	unix_free_vertices(fpl);
> >  }
> >  
> > +static bool unix_vertex_dead(struct unix_vertex *vertex)
> > +{
> > +	struct unix_edge *edge;
> > +	struct unix_sock *u;
> > +	long total_ref;
> > +
> > +	list_for_each_entry(edge, &vertex->edges, vertex_entry) {
> > +		struct unix_vertex *next_vertex = unix_edge_successor(edge);
> > +
> > +		if (!next_vertex)
> > +			return false;
> > +
> > +		if (next_vertex->scc_index != vertex->scc_index)
> > +			return false;
> > +	}
> > +
> > +	edge = list_first_entry(&vertex->edges, typeof(*edge), vertex_entry);
> > +	u = edge->predecessor;
> > +	total_ref = file_count(u->sk.sk_socket->file);
> > +
> > +	if (total_ref != vertex->out_degree)
> > +		return false;
> > +
> > +	return true;
> > +}
> > +
> >  static bool unix_scc_cyclic(struct list_head *scc)
> >  {
> >  	struct unix_vertex *vertex;
> > @@ -350,6 +376,7 @@ static void __unix_walk_scc(struct unix_vertex *vertex)
> >  
> >  	if (vertex->index == vertex->scc_index) {
> >  		struct list_head scc;
> > +		bool dead = true;
> 
> Very minor nit: the above variable 'sounds' alike referring to the
> current vertex, while instead it tracks a global status, what about
> 'all_dead' or 'gc_all'?

Exactly. I'll use scc_dead or gc_scc to be consistent
with unix_vertex_dead().

Thanks!
diff mbox series

Patch

diff --git a/net/unix/garbage.c b/net/unix/garbage.c
index 0eb1610c96d7..060e81be3614 100644
--- a/net/unix/garbage.c
+++ b/net/unix/garbage.c
@@ -288,6 +288,32 @@  void unix_destroy_fpl(struct scm_fp_list *fpl)
 	unix_free_vertices(fpl);
 }
 
+static bool unix_vertex_dead(struct unix_vertex *vertex)
+{
+	struct unix_edge *edge;
+	struct unix_sock *u;
+	long total_ref;
+
+	list_for_each_entry(edge, &vertex->edges, vertex_entry) {
+		struct unix_vertex *next_vertex = unix_edge_successor(edge);
+
+		if (!next_vertex)
+			return false;
+
+		if (next_vertex->scc_index != vertex->scc_index)
+			return false;
+	}
+
+	edge = list_first_entry(&vertex->edges, typeof(*edge), vertex_entry);
+	u = edge->predecessor;
+	total_ref = file_count(u->sk.sk_socket->file);
+
+	if (total_ref != vertex->out_degree)
+		return false;
+
+	return true;
+}
+
 static bool unix_scc_cyclic(struct list_head *scc)
 {
 	struct unix_vertex *vertex;
@@ -350,6 +376,7 @@  static void __unix_walk_scc(struct unix_vertex *vertex)
 
 	if (vertex->index == vertex->scc_index) {
 		struct list_head scc;
+		bool dead = true;
 
 		__list_cut_position(&scc, &vertex_stack, &vertex->scc_entry);
 
@@ -357,6 +384,9 @@  static void __unix_walk_scc(struct unix_vertex *vertex)
 			list_move_tail(&vertex->entry, &unix_visited_vertices);
 
 			vertex->index = unix_vertex_grouped_index;
+
+			if (dead)
+				dead = unix_vertex_dead(vertex);
 		}
 
 		if (!unix_graph_maybe_cyclic)
@@ -392,13 +422,18 @@  static void unix_walk_scc_fast(void)
 	while (!list_empty(&unix_unvisited_vertices)) {
 		struct unix_vertex *vertex;
 		struct list_head scc;
+		bool dead = true;
 
 		vertex = list_first_entry(&unix_unvisited_vertices, typeof(*vertex), entry);
 		list_add(&scc, &vertex->scc_entry);
 
-		list_for_each_entry_reverse(vertex, &scc, scc_entry)
+		list_for_each_entry_reverse(vertex, &scc, scc_entry) {
 			list_move_tail(&vertex->entry, &unix_visited_vertices);
 
+			if (dead)
+				dead = unix_vertex_dead(vertex);
+		}
+
 		list_del(&scc);
 	}