Enable dynamic read logs buffer sizing for incfs

Default buffer size of 4 pages causes many missed log records
because of ring buffer overflows. This change adds a dynamic
sizing, up to 32 pages, that has shown to decrease dropped
records pretty much to nil

Fallback code automatically decreases the buffer size in case
of kernel memory fragmentation - some logs are still much
better than no logs at all

Bug: 203551890
Test: manual, adb install <Apk>; checked for fallback by
  increasing max size to 1024 pages
Change-Id: I0ea46c1ad2534b1dbb5faaead52afab88b66747b
This commit is contained in:
Yurii Zubrytskyi 2021-10-28 14:37:12 -07:00
parent 2c48d37a29
commit 1d7acfddf7

View file

@ -1039,16 +1039,30 @@ binder::Status VoldNativeService::setIncFsMountOptions(
};
auto cleanup =
std::unique_ptr<incfs::Control, decltype(cleanupFunc)>(&incfsControl, cleanupFunc);
if (auto error = incfs::setOptions(
incfsControl,
{.defaultReadTimeoutMs =
enableReadTimeouts ? INCFS_DEFAULT_READ_TIMEOUT_MS : kIncFsReadNoTimeoutMs,
.readLogBufferPages = enableReadLogs ? INCFS_DEFAULT_PAGE_READ_BUFFER_PAGES : 0,
.sysfsName = sysfsName.c_str()});
error < 0) {
return binder::Status::fromServiceSpecificError(error);
}
constexpr auto minReadLogBufferPages = INCFS_DEFAULT_PAGE_READ_BUFFER_PAGES;
constexpr auto maxReadLogBufferPages = 8 * INCFS_DEFAULT_PAGE_READ_BUFFER_PAGES;
auto options = incfs::MountOptions{
.defaultReadTimeoutMs =
enableReadTimeouts ? INCFS_DEFAULT_READ_TIMEOUT_MS : kIncFsReadNoTimeoutMs,
.readLogBufferPages = enableReadLogs ? maxReadLogBufferPages : 0,
.sysfsName = sysfsName.c_str()};
for (;;) {
const auto error = incfs::setOptions(incfsControl, options);
if (!error) {
return Ok();
}
if (!enableReadLogs || error != -ENOMEM) {
return binder::Status::fromServiceSpecificError(error);
}
// In case of memory allocation error retry with a smaller buffer.
options.readLogBufferPages /= 2;
if (options.readLogBufferPages < minReadLogBufferPages) {
return binder::Status::fromServiceSpecificError(error);
}
}
// unreachable, but makes the compiler happy
return Ok();
}