mirror of
https://github.com/mozilla/gecko-dev.git
synced 2025-02-26 04:09:50 +00:00
df91a347b4
This introduces a low memory watcher that dispatches an offthread read of /proc/meminfo every 5000/1000ms depending on memory levels, then determines which information to act on. It works like this: - Get a percentage of `MemAvailable` versus `MemTotal`. - If memory drops below 5% availability, we are in a memory pressure scenario - If `MemAvailable` is not large enough to accommodate a content process, we are in a memory pressure scenario - If we are in a memory pressure scenario, notify the observers from the main thread. The value I decided to use to represent a content process was based on observation and should be adjusted if it is not representative of what we consider a "typical" content process. Differential Revision: https://phabricator.services.mozilla.com/D117972
57 lines
1.8 KiB
C++
57 lines
1.8 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
|
|
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
|
|
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
#ifndef mozilla_AvailableMemoryWatcherUtils_h
|
|
#define mozilla_AvailableMemoryWatcherUtils_h
|
|
|
|
#include "mozilla/Attributes.h"
|
|
#include "nsISupportsUtils.h" // For nsresult
|
|
|
|
namespace mozilla {
|
|
|
|
struct MemoryInfo {
|
|
unsigned long memTotal;
|
|
unsigned long memAvailable;
|
|
};
|
|
// Check /proc/meminfo for low memory. Largely C method for reading
|
|
// /proc/meminfo.
|
|
MOZ_MAYBE_UNUSED
|
|
static nsresult ReadMemoryFile(const char* meminfoPath, MemoryInfo& aResult) {
|
|
FILE* fd;
|
|
if ((fd = fopen(meminfoPath, "r")) == nullptr) {
|
|
// Meminfo somehow unreachable
|
|
return NS_ERROR_FAILURE;
|
|
}
|
|
|
|
char buff[128];
|
|
|
|
/* The first few lines of meminfo look something like this:
|
|
* MemTotal: 65663448 kB
|
|
* MemFree: 57368112 kB
|
|
* MemAvailable: 61852700 kB
|
|
* We mostly care about the available versus the total. We calculate our
|
|
* memory thresholds using this, and when memory drops below 5% we consider
|
|
* this to be a memory pressure event. In practice these lines aren't
|
|
* necessarily in order, but we can simply search for MemTotal
|
|
* and MemAvailable.
|
|
*/
|
|
char namebuffer[20];
|
|
while ((fgets(buff, sizeof(buff), fd)) != nullptr) {
|
|
if (strstr(buff, "MemTotal:")) {
|
|
sscanf(buff, "%s %lu ", namebuffer, &aResult.memTotal);
|
|
}
|
|
if (strstr(buff, "MemAvailable:")) {
|
|
sscanf(buff, "%s %lu ", namebuffer, &aResult.memAvailable);
|
|
}
|
|
}
|
|
fclose(fd);
|
|
return NS_OK;
|
|
}
|
|
|
|
} // namespace mozilla
|
|
|
|
#endif // ifndef mozilla_AvailableMemoryWatcherUtils_h
|