Clean up check_pf allocation pattern. addresses
Commit Message
On Mon, Mar 24, 2014 at 07:14:08PM +0100, Andreas Schwab wrote:
> Ondřej Bílka <neleai@seznam.cz> writes:
>
> > As far as I recall there was a similar patch that did not get in.
> >
> > After I reviewed that I noticed that you could drop alloca altogether.
> >
> > Its only used to construct a single linked list and then copy it to
> > malloced array. Faster way would be to malloc array directly, realloc as
> > necessary.
>
> Sorry, I missed it when I searched for __check_pf. Could you rebase
> your patch? This issue is orthogonal to the alloca issue.
>
Yes, here it is.
I dropped a malloc/free of buf because it only once allocates one page and
check if this is small enough does not make lot of sense.
Second part consist from replacing a creating linked list and copying it to
result by directly creating a result.
* sysdeps/unix/sysv/linux/check_pf.c (make_pf): Simplify
allocation strategy.
Comments
Ondřej Bílka <neleai@seznam.cz> writes:
> diff --git a/sysdeps/unix/sysv/linux/check_pf.c b/sysdeps/unix/sysv/linux/check_pf.c
> index e6a12ed..40b1af2 100644
> --- a/sysdeps/unix/sysv/linux/check_pf.c
> +++ b/sysdeps/unix/sysv/linux/check_pf.c
> @@ -106,6 +106,12 @@ cache_valid_p (void)
> static struct cached_data *
> make_request (int fd, pid_t pid)
> {
> +
Extra empty line.
> @@ -241,40 +230,36 @@ make_request (int fd, pid_t pid)
> }
> }
>
> - struct in6ailist *newp;
> - if (__libc_use_alloca (alloca_used + sizeof (*newp)))
> + if (result_len == 0 || result_len == result_cap)
> {
> - newp = alloca_account (sizeof (*newp), alloca_used);
> - newp->use_malloc = false;
> + result_cap = 2 * result_cap;
> + result = realloc (result, sizeof (*result)
> + + result_cap * sizeof (struct in6addrinfo));
Wrong indent.
> + info->flags = (((ifam->ifa_flags
> & (IFA_F_DEPRECATED
Wrong indent.
Andreas.
@@ -106,6 +106,12 @@ cache_valid_p (void)
static struct cached_data *
make_request (int fd, pid_t pid)
{
+
+ struct cached_data *result = NULL;
+
+ size_t result_len = 0;
+ size_t result_cap = 32;
+
struct req
{
struct nlmsghdr nlh;
@@ -137,20 +143,9 @@ make_request (int fd, pid_t pid)
#else
const size_t buf_size = __getpagesize ();
#endif
- bool use_malloc = false;
char *buf;
- size_t alloca_used = 0;
- if (__libc_use_alloca (buf_size))
- buf = alloca_account (buf_size, alloca_used);
- else
- {
- buf = malloc (buf_size);
- if (buf != NULL)
- use_malloc = true;
- else
- goto out_fail;
- }
+ buf = alloca (buf_size);
struct iovec iov = { buf, buf_size };
@@ -160,13 +155,7 @@ make_request (int fd, pid_t pid)
goto out_fail;
bool done = false;
- struct in6ailist
- {
- struct in6addrinfo info;
- struct in6ailist *next;
- bool use_malloc;
- } *in6ailist = NULL;
- size_t in6ailistlen = 0;
+
bool seen_ipv4 = false;
bool seen_ipv6 = false;
@@ -182,10 +171,10 @@ make_request (int fd, pid_t pid)
ssize_t read_len = TEMP_FAILURE_RETRY (__recvmsg (fd, &msg, 0));
if (read_len < 0)
- goto out_fail2;
+ goto out_fail;
if (msg.msg_flags & MSG_TRUNC)
- goto out_fail2;
+ goto out_fail;
struct nlmsghdr *nlmh;
for (nlmh = (struct nlmsghdr *) buf;
@@ -241,40 +230,36 @@ make_request (int fd, pid_t pid)
}
}
- struct in6ailist *newp;
- if (__libc_use_alloca (alloca_used + sizeof (*newp)))
+ if (result_len == 0 || result_len == result_cap)
{
- newp = alloca_account (sizeof (*newp), alloca_used);
- newp->use_malloc = false;
+ result_cap = 2 * result_cap;
+ result = realloc (result, sizeof (*result)
+ + result_cap * sizeof (struct in6addrinfo));
}
- else
- {
- newp = malloc (sizeof (*newp));
- if (newp == NULL)
- goto out_fail2;
- newp->use_malloc = true;
- }
- newp->info.flags = (((ifam->ifa_flags
+
+ if (!result)
+ goto out_fail;
+
+ struct in6addrinfo *info = &result->in6ai[result_len++];
+
+ info->flags = (((ifam->ifa_flags
& (IFA_F_DEPRECATED
| IFA_F_OPTIMISTIC))
? in6ai_deprecated : 0)
| ((ifam->ifa_flags
& IFA_F_HOMEADDRESS)
? in6ai_homeaddress : 0));
- newp->info.prefixlen = ifam->ifa_prefixlen;
- newp->info.index = ifam->ifa_index;
+ info->prefixlen = ifam->ifa_prefixlen;
+ info->index = ifam->ifa_index;
if (ifam->ifa_family == AF_INET)
{
- newp->info.addr[0] = 0;
- newp->info.addr[1] = 0;
- newp->info.addr[2] = htonl (0xffff);
- newp->info.addr[3] = *(const in_addr_t *) address;
+ info->addr[0] = 0;
+ info->addr[1] = 0;
+ info->addr[2] = htonl (0xffff);
+ info->addr[3] = *(const in_addr_t *) address;
}
else
- memcpy (newp->info.addr, address, sizeof (newp->info.addr));
- newp->next = in6ailist;
- in6ailist = newp;
- ++in6ailistlen;
+ memcpy (info->addr, address, sizeof (info->addr));
}
else if (nlmh->nlmsg_type == NLMSG_DONE)
/* We found the end, leave the loop. */
@@ -283,53 +268,29 @@ make_request (int fd, pid_t pid)
}
while (! done);
- struct cached_data *result;
- if (seen_ipv6 && in6ailist != NULL)
+ if (seen_ipv6 && result != NULL)
{
- result = malloc (sizeof (*result)
- + in6ailistlen * sizeof (struct in6addrinfo));
- if (result == NULL)
- goto out_fail2;
-
result->timestamp = get_nl_timestamp ();
result->usecnt = 2;
result->seen_ipv4 = seen_ipv4;
result->seen_ipv6 = true;
- result->in6ailen = in6ailistlen;
-
- do
- {
- result->in6ai[--in6ailistlen] = in6ailist->info;
- struct in6ailist *next = in6ailist->next;
- if (in6ailist->use_malloc)
- free (in6ailist);
- in6ailist = next;
- }
- while (in6ailist != NULL);
+ result->in6ailen = result_len;
}
else
{
+ free (result);
+
atomic_add (&noai6ai_cached.usecnt, 2);
noai6ai_cached.seen_ipv4 = seen_ipv4;
noai6ai_cached.seen_ipv6 = seen_ipv6;
result = &noai6ai_cached;
}
- if (use_malloc)
- free (buf);
return result;
- out_fail2:
- while (in6ailist != NULL)
- {
- struct in6ailist *next = in6ailist->next;
- if (in6ailist->use_malloc)
- free (in6ailist);
- in6ailist = next;
- }
out_fail:
- if (use_malloc)
- free (buf);
+
+ free (result);
return NULL;
}