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authorJoel Fernandes2018-07-17 15:00:17 -0500
committerJoel Fernandes2018-07-17 19:02:44 -0500
commit56cd651e7ae16173f9c24fd49cd76e8c61f0756c (patch)
treec3cd72df12cf9435fd0da938e712e58054d3896b /libcutils/ashmem-dev.cpp
parenta73ea65c5aa40fbd3faf05ece4de4c7acc7a8564 (diff)
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libcutils: ashmem: Avoid doing fd checks for ashmem calls
Callers already verify that they are calling ashmem API on a valid fd by calling ashmem_valid first. Lets make the fstat syscall only if the ioctl returns -ENOTTY. This means in the regular case, only 1 syscall is needed (ioctl) vs the current 2 (fstat+ioctl). Some data to show improvements in reduction of vfs_getattr calls in the kernel by 10x when doing a camera. Test: Boot and camera CTS Bug: 111418894 Change-Id: I992620bbe44355e54ba19eeac81da586c5e5a6e0 Signed-off-by: Joel Fernandes <joelaf@google.com>
Diffstat (limited to 'libcutils/ashmem-dev.cpp')
-rw-r--r--libcutils/ashmem-dev.cpp36
1 files changed, 11 insertions, 25 deletions
diff --git a/libcutils/ashmem-dev.cpp b/libcutils/ashmem-dev.cpp
index 15ace0e64..0cc4fc084 100644
--- a/libcutils/ashmem-dev.cpp
+++ b/libcutils/ashmem-dev.cpp
@@ -90,7 +90,7 @@ static int __ashmem_is_ashmem(int fd, int fatal)
90 dev_t rdev; 90 dev_t rdev;
91 struct stat st; 91 struct stat st;
92 92
93 if (TEMP_FAILURE_RETRY(fstat(fd, &st)) < 0) { 93 if (fstat(fd, &st) < 0) {
94 return -1; 94 return -1;
95 } 95 }
96 96
@@ -135,6 +135,12 @@ static int __ashmem_is_ashmem(int fd, int fatal)
135 return -1; 135 return -1;
136} 136}
137 137
138static int __ashmem_check_failure(int fd, int result)
139{
140 if (result == -1 && errno == ENOTTY) __ashmem_is_ashmem(fd, 1);
141 return result;
142}
143
138int ashmem_valid(int fd) 144int ashmem_valid(int fd)
139{ 145{
140 return __ashmem_is_ashmem(fd, 0) >= 0; 146 return __ashmem_is_ashmem(fd, 0) >= 0;
@@ -182,12 +188,7 @@ error:
182 188
183int ashmem_set_prot_region(int fd, int prot) 189int ashmem_set_prot_region(int fd, int prot)
184{ 190{
185 int ret = __ashmem_is_ashmem(fd, 1); 191 return __ashmem_check_failure(fd, TEMP_FAILURE_RETRY(ioctl(fd, ASHMEM_SET_PROT_MASK, prot)));
186 if (ret < 0) {
187 return ret;
188 }
189
190 return TEMP_FAILURE_RETRY(ioctl(fd, ASHMEM_SET_PROT_MASK, prot));
191} 192}
192 193
193int ashmem_pin_region(int fd, size_t offset, size_t len) 194int ashmem_pin_region(int fd, size_t offset, size_t len)
@@ -195,12 +196,7 @@ int ashmem_pin_region(int fd, size_t offset, size_t len)
195 // TODO: should LP64 reject too-large offset/len? 196 // TODO: should LP64 reject too-large offset/len?
196 ashmem_pin pin = { static_cast<uint32_t>(offset), static_cast<uint32_t>(len) }; 197 ashmem_pin pin = { static_cast<uint32_t>(offset), static_cast<uint32_t>(len) };
197 198
198 int ret = __ashmem_is_ashmem(fd, 1); 199 return __ashmem_check_failure(fd, TEMP_FAILURE_RETRY(ioctl(fd, ASHMEM_PIN, &pin)));
199 if (ret < 0) {
200 return ret;
201 }
202
203 return TEMP_FAILURE_RETRY(ioctl(fd, ASHMEM_PIN, &pin));
204} 200}
205 201
206int ashmem_unpin_region(int fd, size_t offset, size_t len) 202int ashmem_unpin_region(int fd, size_t offset, size_t len)
@@ -208,20 +204,10 @@ int ashmem_unpin_region(int fd, size_t offset, size_t len)
208 // TODO: should LP64 reject too-large offset/len? 204 // TODO: should LP64 reject too-large offset/len?
209 ashmem_pin pin = { static_cast<uint32_t>(offset), static_cast<uint32_t>(len) }; 205 ashmem_pin pin = { static_cast<uint32_t>(offset), static_cast<uint32_t>(len) };
210 206
211 int ret = __ashmem_is_ashmem(fd, 1); 207 return __ashmem_check_failure(fd, TEMP_FAILURE_RETRY(ioctl(fd, ASHMEM_UNPIN, &pin)));
212 if (ret < 0) {
213 return ret;
214 }
215
216 return TEMP_FAILURE_RETRY(ioctl(fd, ASHMEM_UNPIN, &pin));
217} 208}
218 209
219int ashmem_get_size_region(int fd) 210int ashmem_get_size_region(int fd)
220{ 211{
221 int ret = __ashmem_is_ashmem(fd, 1); 212 return __ashmem_check_failure(fd, TEMP_FAILURE_RETRY(ioctl(fd, ASHMEM_GET_SIZE, NULL)));
222 if (ret < 0) {
223 return ret;
224 }
225
226 return TEMP_FAILURE_RETRY(ioctl(fd, ASHMEM_GET_SIZE, NULL));
227} 213}