[Devel] [PATCH RHEL7 COMMIT] net/sctp: Replace in/out stream arrays with flex_array
Konstantin Khorenko
khorenko at virtuozzo.com
Fri Aug 17 14:34:34 MSK 2018
The commit is pushed to "branch-rh7-3.10.0-862.11.6.vz7.71.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-862.11.6.vz7.71.2
------>
commit 87f39da76b8b3d05363c2789c9286c4c9375a1a0
Author: Oleg Babin <obabin at virtuozzo.com>
Date: Mon Apr 9 20:40:37 2018 +0300
net/sctp: Replace in/out stream arrays with flex_array
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);
}
More information about the Devel
mailing list