[PATCH libdrm 1/6] amdgpu: stop using the hash table for fd_tab

[Christian König]

We have so few devices that just walking a linked list is probably
faster.

Signed-off-by: Christian König <christian.koe...@amd.com>
---
 amdgpu/amdgpu_device.c   | 49 ++++++++++++++++--------------------------------
 amdgpu/amdgpu_internal.h |  1 +
 2 files changed, 17 insertions(+), 33 deletions(-)

diff --git a/amdgpu/amdgpu_device.c b/amdgpu/amdgpu_device.c
index d7aec6a4..38fd186d 100644
--- a/amdgpu/amdgpu_device.c
+++ b/amdgpu/amdgpu_device.c
@@ -43,10 +43,9 @@
 #include "util_math.h"
 
 #define PTR_TO_UINT(x) ((unsigned)((intptr_t)(x)))
-#define UINT_TO_PTR(x) ((void *)((intptr_t)(x)))
 
 static pthread_mutex_t fd_mutex = PTHREAD_MUTEX_INITIALIZER;
-static struct util_hash_table *fd_tab;
+static amdgpu_device_handle fd_list;
 
 static unsigned handle_hash(void *key)
 {
@@ -58,28 +57,8 @@ static int handle_compare(void *key1, void *key2)
        return PTR_TO_UINT(key1) != PTR_TO_UINT(key2);
 }
 
-static unsigned fd_hash(void *key)
+static int fd_compare(int fd1, int fd2)
 {
-       int fd = PTR_TO_UINT(key);
-       char *name = drmGetPrimaryDeviceNameFromFd(fd);
-       unsigned result = 0;
-       char *c;
-
-       if (name == NULL)
-               return 0;
-
-       for (c = name; *c; ++c)
-               result += *c;
-
-       free(name);
-
-       return result;
-}
-
-static int fd_compare(void *key1, void *key2)
-{
-       int fd1 = PTR_TO_UINT(key1);
-       int fd2 = PTR_TO_UINT(key2);
        char *name1 = drmGetPrimaryDeviceNameFromFd(fd1);
        char *name2 = drmGetPrimaryDeviceNameFromFd(fd2);
        int result;
@@ -127,16 +106,17 @@ static int amdgpu_get_auth(int fd, int *auth)
 
 static void amdgpu_device_free_internal(amdgpu_device_handle dev)
 {
+       amdgpu_device_handle *node = &fd_list;
+
        pthread_mutex_lock(&fd_mutex);
-       util_hash_table_remove(fd_tab, UINT_TO_PTR(dev->fd));
-       if (util_hash_table_count(fd_tab) == 0) {
-               util_hash_table_destroy(fd_tab);
-               fd_tab = NULL;
-       }
+       while (*node != dev && (*node)->next)
+               node = &(*node)->next;
+       *node = (*node)->next;
+       pthread_mutex_unlock(&fd_mutex);
+
        close(dev->fd);
        if ((dev->flink_fd >= 0) && (dev->fd != dev->flink_fd))
                close(dev->flink_fd);
-       pthread_mutex_unlock(&fd_mutex);
 
        amdgpu_vamgr_deinit(&dev->vamgr_32);
        amdgpu_vamgr_deinit(&dev->vamgr);
@@ -187,8 +167,6 @@ int amdgpu_device_initialize(int fd,
        *device_handle = NULL;
 
        pthread_mutex_lock(&fd_mutex);
-       if (!fd_tab)
-               fd_tab = util_hash_table_create(fd_hash, fd_compare);
        r = amdgpu_get_auth(fd, &flag_auth);
        if (r) {
                fprintf(stderr, "%s: amdgpu_get_auth (1) failed (%i)\n",
@@ -196,7 +174,11 @@ int amdgpu_device_initialize(int fd,
                pthread_mutex_unlock(&fd_mutex);
                return r;
        }
-       dev = util_hash_table_get(fd_tab, UINT_TO_PTR(fd));
+
+       for (dev = fd_list; dev; dev = dev->next)
+               if (fd_compare(dev->fd, fd) == 0)
+                       break;
+
        if (dev) {
                r = amdgpu_get_auth(dev->fd, &flag_authexist);
                if (r) {
@@ -297,7 +279,8 @@ int amdgpu_device_initialize(int fd,
        *major_version = dev->major_version;
        *minor_version = dev->minor_version;
        *device_handle = dev;
-       util_hash_table_set(fd_tab, UINT_TO_PTR(dev->fd), dev);
+       dev->next = fd_list;
+       fd_list = dev;
        pthread_mutex_unlock(&fd_mutex);
 
        return 0;
diff --git a/amdgpu/amdgpu_internal.h b/amdgpu/amdgpu_internal.h
index 99b8ce0b..83012cab 100644
--- a/amdgpu/amdgpu_internal.h
+++ b/amdgpu/amdgpu_internal.h
@@ -65,6 +65,7 @@ struct amdgpu_va {
 
 struct amdgpu_device {
        atomic_t refcount;
+       struct amdgpu_device *next;
        int fd;
        int flink_fd;
        unsigned major_version;
-- 
2.14.1

_______________________________________________
amd-gfx mailing list
amd-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx