Revision 9c29bcd189f4ab1644b7125713602532d0aefdb7 authored by Eric Dumazet on 21 September 2018, 22:27:48 UTC, committed by David S. Miller on 24 September 2018, 04:55:25 UTC
As diagnosed by Song Liu, ndo_poll_controller() can be very dangerous on loaded hosts, since the cpu calling ndo_poll_controller() might steal all NAPI contexts (for all RX/TX queues of the NIC). This capture can last for unlimited amount of time, since one cpu is generally not able to drain all the queues under load. mlx5 uses NAPI for TX completions, so we better let core networking stack call the napi->poll() to avoid the capture. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent a24b66c
expr.y
/* Simple expression parser */
%{
#include "util.h"
#include "util/debug.h"
#define IN_EXPR_Y 1
#include "expr.h"
#include "smt.h"
#include <string.h>
#define MAXIDLEN 256
%}
%pure-parser
%parse-param { double *final_val }
%parse-param { struct parse_ctx *ctx }
%parse-param { const char **pp }
%lex-param { const char **pp }
%union {
double num;
char id[MAXIDLEN+1];
}
%token <num> NUMBER
%token <id> ID
%token MIN MAX IF ELSE SMT_ON
%left MIN MAX IF
%left '|'
%left '^'
%left '&'
%left '-' '+'
%left '*' '/' '%'
%left NEG NOT
%type <num> expr if_expr
%{
static int expr__lex(YYSTYPE *res, const char **pp);
static void expr__error(double *final_val __maybe_unused,
struct parse_ctx *ctx __maybe_unused,
const char **pp __maybe_unused,
const char *s)
{
pr_debug("%s\n", s);
}
static int lookup_id(struct parse_ctx *ctx, char *id, double *val)
{
int i;
for (i = 0; i < ctx->num_ids; i++) {
if (!strcasecmp(ctx->ids[i].name, id)) {
*val = ctx->ids[i].val;
return 0;
}
}
return -1;
}
%}
%%
all_expr: if_expr { *final_val = $1; }
;
if_expr:
expr IF expr ELSE expr { $$ = $3 ? $1 : $5; }
| expr
;
expr: NUMBER
| ID { if (lookup_id(ctx, $1, &$$) < 0) {
pr_debug("%s not found\n", $1);
YYABORT;
}
}
| expr '|' expr { $$ = (long)$1 | (long)$3; }
| expr '&' expr { $$ = (long)$1 & (long)$3; }
| expr '^' expr { $$ = (long)$1 ^ (long)$3; }
| expr '+' expr { $$ = $1 + $3; }
| expr '-' expr { $$ = $1 - $3; }
| expr '*' expr { $$ = $1 * $3; }
| expr '/' expr { if ($3 == 0) YYABORT; $$ = $1 / $3; }
| expr '%' expr { if ((long)$3 == 0) YYABORT; $$ = (long)$1 % (long)$3; }
| '-' expr %prec NEG { $$ = -$2; }
| '(' if_expr ')' { $$ = $2; }
| MIN '(' expr ',' expr ')' { $$ = $3 < $5 ? $3 : $5; }
| MAX '(' expr ',' expr ')' { $$ = $3 > $5 ? $3 : $5; }
| SMT_ON { $$ = smt_on() > 0; }
;
%%
static int expr__symbol(YYSTYPE *res, const char *p, const char **pp)
{
char *dst = res->id;
const char *s = p;
if (*p == '#')
*dst++ = *p++;
while (isalnum(*p) || *p == '_' || *p == '.' || *p == ':' || *p == '@' || *p == '\\') {
if (p - s >= MAXIDLEN)
return -1;
/*
* Allow @ instead of / to be able to specify pmu/event/ without
* conflicts with normal division.
*/
if (*p == '@')
*dst++ = '/';
else if (*p == '\\')
*dst++ = *++p;
else
*dst++ = *p;
p++;
}
*dst = 0;
*pp = p;
dst = res->id;
switch (dst[0]) {
case 'm':
if (!strcmp(dst, "min"))
return MIN;
if (!strcmp(dst, "max"))
return MAX;
break;
case 'i':
if (!strcmp(dst, "if"))
return IF;
break;
case 'e':
if (!strcmp(dst, "else"))
return ELSE;
break;
case '#':
if (!strcasecmp(dst, "#smt_on"))
return SMT_ON;
break;
}
return ID;
}
static int expr__lex(YYSTYPE *res, const char **pp)
{
int tok;
const char *s;
const char *p = *pp;
while (isspace(*p))
p++;
s = p;
switch (*p++) {
case '#':
case 'a' ... 'z':
case 'A' ... 'Z':
return expr__symbol(res, p - 1, pp);
case '0' ... '9': case '.':
res->num = strtod(s, (char **)&p);
tok = NUMBER;
break;
default:
tok = *s;
break;
}
*pp = p;
return tok;
}
/* Caller must make sure id is allocated */
void expr__add_id(struct parse_ctx *ctx, const char *name, double val)
{
int idx;
assert(ctx->num_ids < MAX_PARSE_ID);
idx = ctx->num_ids++;
ctx->ids[idx].name = name;
ctx->ids[idx].val = val;
}
void expr__ctx_init(struct parse_ctx *ctx)
{
ctx->num_ids = 0;
}
static bool already_seen(const char *val, const char *one, const char **other,
int num_other)
{
int i;
if (one && !strcasecmp(one, val))
return true;
for (i = 0; i < num_other; i++)
if (!strcasecmp(other[i], val))
return true;
return false;
}
int expr__find_other(const char *p, const char *one, const char ***other,
int *num_otherp)
{
const char *orig = p;
int err = -1;
int num_other;
*other = malloc((EXPR_MAX_OTHER + 1) * sizeof(char *));
if (!*other)
return -1;
num_other = 0;
for (;;) {
YYSTYPE val;
int tok = expr__lex(&val, &p);
if (tok == 0) {
err = 0;
break;
}
if (tok == ID && !already_seen(val.id, one, *other, num_other)) {
if (num_other >= EXPR_MAX_OTHER - 1) {
pr_debug("Too many extra events in %s\n", orig);
break;
}
(*other)[num_other] = strdup(val.id);
if (!(*other)[num_other])
return -1;
num_other++;
}
}
(*other)[num_other] = NULL;
*num_otherp = num_other;
if (err) {
*num_otherp = 0;
free(*other);
*other = NULL;
}
return err;
}
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