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author | Olof Johansson <olof@lixom.net> | 2019-12-05 13:16:58 -0800 |
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committer | Olof Johansson <olof@lixom.net> | 2019-12-05 13:18:54 -0800 |
commit | 942e6f8a8314e5550e254519dfba4ccd5170421d (patch) | |
tree | 75ec655b440fbc1c454247af38b5596dd8c78de9 /tools/perf/util/fncache.c | |
parent | ARM: pxa: Fix resource properties (diff) | |
parent | Merge tag 'armsoc-defconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc (diff) | |
download | linux-dev-942e6f8a8314e5550e254519dfba4ccd5170421d.tar.xz linux-dev-942e6f8a8314e5550e254519dfba4ccd5170421d.zip |
Merge mainline/master into arm/fixes
This brings in the mainline tree right after armsoc contents was merged
this release cycle, so that we can re-run savedefconfig, etc.
Signed-off-by: Olof Johansson <olof@lixom.net>
Diffstat (limited to 'tools/perf/util/fncache.c')
-rw-r--r-- | tools/perf/util/fncache.c | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/tools/perf/util/fncache.c b/tools/perf/util/fncache.c new file mode 100644 index 000000000000..6225cbc52310 --- /dev/null +++ b/tools/perf/util/fncache.c @@ -0,0 +1,63 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Manage a cache of file names' existence */ +#include <stdlib.h> +#include <unistd.h> +#include <string.h> +#include <linux/list.h> +#include "fncache.h" + +struct fncache { + struct hlist_node nd; + bool res; + char name[]; +}; + +#define FNHSIZE 61 + +static struct hlist_head fncache_hash[FNHSIZE]; + +unsigned shash(const unsigned char *s) +{ + unsigned h = 0; + while (*s) + h = 65599 * h + *s++; + return h ^ (h >> 16); +} + +static bool lookup_fncache(const char *name, bool *res) +{ + int h = shash((const unsigned char *)name) % FNHSIZE; + struct fncache *n; + + hlist_for_each_entry(n, &fncache_hash[h], nd) { + if (!strcmp(n->name, name)) { + *res = n->res; + return true; + } + } + return false; +} + +static void update_fncache(const char *name, bool res) +{ + struct fncache *n = malloc(sizeof(struct fncache) + strlen(name) + 1); + int h = shash((const unsigned char *)name) % FNHSIZE; + + if (!n) + return; + strcpy(n->name, name); + n->res = res; + hlist_add_head(&n->nd, &fncache_hash[h]); +} + +/* No LRU, only use when bounded in some other way. */ +bool file_available(const char *name) +{ + bool res; + + if (lookup_fncache(name, &res)) + return res; + res = access(name, R_OK) == 0; + update_fncache(name, res); + return res; +} |