[Devel] [PATCH vz7 v3] net/sctp: Replace in/out stream arrays with flex_array
Konstantin Khorenko
khorenko at virtuozzo.com
Fri Aug 17 14:32:02 MSK 2018
From: Oleg Babin <obabin at virtuozzo.com>
SCTP protocol allocates TCB on receiving INIT and COOKIE ECHO chunks
which specify input and output stream count. As the total count of
those streams can be up to (2^16 - 1) of each type, it is possible
to occupy a fifth order of memory for only one type of streams. As
allocation can happen in a softirq contex with GFP_ATOMIC flag set
and we actually do not need the memory to be physically contiguous,
for performance reasons we use flex_array which allocates memory on
a per-page basis.
v2: Use flex_array instead of allocating pages manually.
v3: Initialize stream->len on stream allocation.
Mainstream code is different, so patches do differ significantly.
0d493b4d0be3 ("net/sctp: Replace in/out stream arrays with flex_array")
05364ca03cfd ("net/sctp: Make wrappers for accessing in/out streams")
https://jira.sw.ru/browse/PSBM-82552
Signed-off-by: Oleg Babin <obabin at virtuozzo.com>
Acked-by: Konstantin Khorenko <khorenko at virtuozzo.com>
Tested:
run netperf (1 stream) and sctp_test (65535 streams)
on an empty node and on node with memory highly fragmented.
---
include/net/sctp/structs.h | 26 ++++++++----
net/sctp/ssnmap.c | 100 ++++++++++++++++++++++-----------------------
2 files changed, 66 insertions(+), 60 deletions(-)
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 6bcd9d18b751..432affdacd7a 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -64,6 +64,7 @@
#include <linux/atomic.h> /* This gets us atomic counters. */
#include <linux/skbuff.h> /* We need sk_buff_head. */
#include <linux/workqueue.h> /* We need tq_struct. */
+#include <linux/flex_array.h> /* We need flex_array. */
#include <linux/sctp.h> /* We need sctp* header structs. */
#include <net/sctp/auth.h> /* We need auth specific structs */
#include <net/ip.h> /* For inet_skb_parm */
@@ -396,10 +397,17 @@ typedef struct sctp_sender_hb_info {
*
* This is the structure we use to track both our outbound and inbound
* SSN, or Stream Sequence Numbers.
+ *
+ * As the total count of input or output streams can be up to (2^16 - 1)
+ * of each type, it is possible to occupy a fifth order of memory for
+ * only one type of streams. As allocation can happen in a softirq
+ * contex with GFP_ATOMIC flag set and we actually do not need the memory
+ * to be physically contiguous, for performance reasons we use flex_array
+ * which allocates memory on a per-page basis.
*/
struct sctp_stream {
- __u16 *ssn;
+ struct flex_array *ssn;
unsigned int len;
};
@@ -408,30 +416,32 @@ struct sctp_ssnmap {
struct sctp_stream out;
};
-struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out,
- gfp_t gfp);
+struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out, gfp_t gfp);
void sctp_ssnmap_free(struct sctp_ssnmap *map);
void sctp_ssnmap_clear(struct sctp_ssnmap *map);
/* What is the current SSN number for this stream? */
static inline __u16 sctp_ssn_peek(struct sctp_stream *stream, __u16 id)
{
- return stream->ssn[id];
+ __u16 *ssnp = flex_array_get(stream->ssn, id);
+ return *ssnp;
}
/* Return the next SSN number for this stream. */
static inline __u16 sctp_ssn_next(struct sctp_stream *stream, __u16 id)
{
- return stream->ssn[id]++;
+ __u16 *ssnp = flex_array_get(stream->ssn, id);
+ return (*ssnp)++;
}
/* Skip over this ssn and all below. */
-static inline void sctp_ssn_skip(struct sctp_stream *stream, __u16 id,
+static inline void sctp_ssn_skip(struct sctp_stream *stream, __u16 id,
__u16 ssn)
{
- stream->ssn[id] = ssn+1;
+ __u16 *ssnp = flex_array_get(stream->ssn, id);
+ *ssnp = ssn + 1;
}
-
+
/*
* Pointers to address related SCTP functions.
* (i.e. things that depend on the address family.)
diff --git a/net/sctp/ssnmap.c b/net/sctp/ssnmap.c
index da8603523808..2a6f38bed1db 100644
--- a/net/sctp/ssnmap.c
+++ b/net/sctp/ssnmap.c
@@ -41,37 +41,58 @@
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>
-static struct sctp_ssnmap *sctp_ssnmap_init(struct sctp_ssnmap *map, __u16 in,
- __u16 out);
+/* Allocate memory pages for one type of stream (in or out). */
+static int sctp_stream_alloc(struct sctp_stream *stream, __u16 len, gfp_t gfp)
+{
+ int err = -ENOMEM;
+
+ stream->ssn = flex_array_alloc(sizeof(__u16), len, gfp);
+ if (stream->ssn) {
+ err = flex_array_prealloc(stream->ssn, 0, len, gfp);
+ if (err) {
+ flex_array_free(stream->ssn);
+ stream->ssn = NULL;
+ }
+ stream->len = len;
+ }
+
+ return err;
+}
-/* Storage size needed for map includes 2 headers and then the
- * specific needs of in or out streams.
- */
-static inline size_t sctp_ssnmap_size(__u16 in, __u16 out)
+/* Free memory pages for one type of stream (in or out). */
+static void sctp_stream_free(struct sctp_stream *stream)
{
- return sizeof(struct sctp_ssnmap) + (in + out) * sizeof(__u16);
+ if (stream->ssn)
+ flex_array_free(stream->ssn);
}
+/* Clear all SSNs for one type of stream (in or out). */
+static void sctp_stream_clear(struct sctp_stream *stream)
+{
+ unsigned int i;
+
+ for (i = 0; i < stream->len; i++)
+ flex_array_clear(stream->ssn, i);
+}
/* Create a new sctp_ssnmap.
- * Allocate room to store at least 'len' contiguous TSNs.
+ * Allocate room to store at least 'in' + 'out' SSNs.
*/
-struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out,
- gfp_t gfp)
+struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out, gfp_t gfp)
{
struct sctp_ssnmap *retval;
- int size;
-
- size = sctp_ssnmap_size(in, out);
- if (size <= KMALLOC_MAX_SIZE)
- retval = kmalloc(size, gfp);
- else
- retval = (struct sctp_ssnmap *)
- __get_free_pages(gfp, get_order(size));
+ int err;
+
+ retval = (struct sctp_ssnmap *)kzalloc(sizeof(struct sctp_ssnmap), gfp);
if (!retval)
goto fail;
- if (!sctp_ssnmap_init(retval, in, out))
+ err = sctp_stream_alloc(&retval->in, in, gfp);
+ if (err)
+ goto fail_map;
+
+ err = sctp_stream_alloc(&retval->out, out, gfp);
+ if (err)
goto fail_map;
SCTP_DBG_OBJCNT_INC(ssnmap);
@@ -79,54 +100,29 @@ struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out,
return retval;
fail_map:
- if (size <= KMALLOC_MAX_SIZE)
- kfree(retval);
- else
- free_pages((unsigned long)retval, get_order(size));
+ sctp_stream_free(&retval->in);
+ sctp_stream_free(&retval->out);
+ kfree(retval);
fail:
return NULL;
}
-
-/* Initialize a block of memory as a ssnmap. */
-static struct sctp_ssnmap *sctp_ssnmap_init(struct sctp_ssnmap *map, __u16 in,
- __u16 out)
-{
- memset(map, 0x00, sctp_ssnmap_size(in, out));
-
- /* Start 'in' stream just after the map header. */
- map->in.ssn = (__u16 *)&map[1];
- map->in.len = in;
-
- /* Start 'out' stream just after 'in'. */
- map->out.ssn = &map->in.ssn[in];
- map->out.len = out;
-
- return map;
-}
-
/* Clear out the ssnmap streams. */
void sctp_ssnmap_clear(struct sctp_ssnmap *map)
{
- size_t size;
-
- size = (map->in.len + map->out.len) * sizeof(__u16);
- memset(map->in.ssn, 0x00, size);
+ sctp_stream_clear(&map->in);
+ sctp_stream_clear(&map->out);
}
/* Dispose of a ssnmap. */
void sctp_ssnmap_free(struct sctp_ssnmap *map)
{
- int size;
-
if (unlikely(!map))
return;
- size = sctp_ssnmap_size(map->in.len, map->out.len);
- if (size <= KMALLOC_MAX_SIZE)
- kfree(map);
- else
- free_pages((unsigned long)map, get_order(size));
+ sctp_stream_free(&map->in);
+ sctp_stream_free(&map->out);
+ kfree(map);
SCTP_DBG_OBJCNT_DEC(ssnmap);
}
--
2.15.1
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