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Commit f2e011da authored by Lee Shombert's avatar Lee Shombert
Browse files

Binder cache for getPackagesForUid(). 

Bug: 140788621

This changes adds a binder cache for the getPackagesForUid() binder call.

Test: A special build that puts the PropertyInvalidatedCache in
verification mode was loaded on the device.  Then one iteration of
MPTS was executed.  No cache inconsistencies were found and no SELinux
violations (associated with the binder cache) were found.  The number
of cache misses was approximately 15% of the total binder calls.
84.5% of all binder calls went through the cache.  The bulk of the
calls that bypassed the cache were singletons: one call per process.
These calls would not be helped by a cache anyway.

Besides the MPTS run, tested by switching between users.

Change-Id: I9a5fb3b7bced031d568aa50b4f3cc495433fcbe7
parent 0d30c924

core/java/android/app/ApplicationPackageManager.java

+82 −5
Original line number Diff line number Diff line
@@ -110,6 +110,7 @@ import libcore.util.EmptyArray; 


import java.lang.ref.WeakReference;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collections;

import java.util.Iterator;

import java.util.List;
@@ -942,14 +943,90 @@ public class ApplicationPackageManager extends PackageManager { 
        }

    }



    /**

     * Wrap the cached value in a class that does deep compares on string

     * arrays.  The comparison is needed only for the verification mode of

     * PropertyInvalidatedCache; this mode is only enabled for debugging.

     * The return result is an array of strings but the order in the array

     * is not important.  To properly compare two arrays, the arrays are

     * sorted before the comparison.

     */

    private static class GetPackagesForUidResult {

        private final String [] mValue;

        GetPackagesForUidResult(String []s) {

            mValue = s;

        }

        public String[] value() {

            return mValue;

        }

        @Override

    public String[] getPackagesForUid(int uid) {

        public String toString() {

            return Arrays.toString(mValue);

        }

        @Override

        public int hashCode() {

            return Arrays.hashCode(mValue);

        }

        /**

         * Arrays.sort() throws an NPE if passed a null pointer, so nulls

         * are handled first.

         */

        @Override

        public boolean equals(Object o) {

            if (o instanceof GetPackagesForUidResult) {

                String [] r = ((GetPackagesForUidResult) o).mValue;

                String [] l = mValue;

                if ((r == null) != (l == null)) {

                    return false;

                } else if (r == null) {

                    return true;

                }

                // Both arrays are non-null.  Sort before comparing.

                Arrays.sort(r);

                Arrays.sort(l);

                return Arrays.equals(l, r);

            } else {

                return false;

            }

        }

    }



    private static final String CACHE_KEY_PACKAGES_FOR_UID_PROPERTY =

            "cache_key.get_packages_for_uid";

    private static final PropertyInvalidatedCache<Integer, GetPackagesForUidResult>

            mGetPackagesForUidCache =

            new PropertyInvalidatedCache<Integer, GetPackagesForUidResult>(

                32, CACHE_KEY_PACKAGES_FOR_UID_PROPERTY) {

                @Override

                protected GetPackagesForUidResult recompute(Integer uid) {

                    try {

            return mPM.getPackagesForUid(uid);

                        return new GetPackagesForUidResult(

                            ActivityThread.currentActivityThread().

                            getPackageManager().getPackagesForUid(uid));

                    } catch (RemoteException e) {

                        throw e.rethrowFromSystemServer();

                    }

                }

                @Override

                public String queryToString(Integer uid) {

                    return String.format("uid=%d", uid.intValue());

                }

            };



    @Override

    public String[] getPackagesForUid(int uid) {

        return mGetPackagesForUidCache.query(uid).value();

    }



    /** @hide */

    public static void disableGetPackagesForUidCache() {

        mGetPackagesForUidCache.disableLocal();

    }



    /** @hide */

    public static void invalidateGetPackagesForUidCache() {

        PropertyInvalidatedCache.invalidateCache(CACHE_KEY_PACKAGES_FOR_UID_PROPERTY);

    }



    @Override

    public String getNameForUid(int uid) {

services/core/java/com/android/server/pm/PackageManagerService.java

+10 −1
Original line number Diff line number Diff line
@@ -2654,6 +2654,9 @@ public class PackageManagerService extends IPackageManager.Stub 
    public PackageManagerService(Injector injector, boolean onlyCore, boolean factoryTest) {

        PackageManager.disableApplicationInfoCache();

        PackageManager.disablePackageInfoCache();

        ApplicationPackageManager.invalidateGetPackagesForUidCache();

        ApplicationPackageManager.disableGetPackagesForUidCache();

        ApplicationPackageManager.invalidateHasSystemFeatureCache();















        // Avoid invalidation-thrashing by preventing cache invalidations from causing property















        // writes if the cache isn't enabled yet.  We re-enable writes later when we're










@@ -2747,7 +2750,6 @@ public class PackageManagerService extends IPackageManager.Stub













        t.traceBegin("get system config");















        SystemConfig systemConfig = SystemConfig.getInstance();















        mAvailableFeatures = systemConfig.getAvailableFeatures();













        ApplicationPackageManager.invalidateHasSystemFeatureCache();















        t.traceEnd();





























        mProtectedPackages = new ProtectedPackages(mContext);










@@ -5947,6 +5949,11 @@ public class PackageManagerService extends IPackageManager.Stub













     * </ol>















     * The second is an artifact of the current data structures and should be fixed. See















     * b/111075456 for one such instance.













     * This binder API is cached.  If the algorithm in this method changes,













     * or if the underlying objecs (as returned by getSettingLPr()) change













     * then the logic that invalidates the cache must be revisited.  See













     * calls to invalidateGetPackagesForUidCache() to locate the points at













     * which the cache is invalidated.















     */















    @Override















    public String[] getPackagesForUid(int uid) {










@@ -16216,6 +16223,7 @@ public class PackageManagerService extends IPackageManager.Stub













                updateInstantAppInstallerLocked(packageName);















            }















        }













        ApplicationPackageManager.invalidateGetPackagesForUidCache();















    }





























    /**










@@ -17834,6 +17842,7 @@ public class PackageManagerService extends IPackageManager.Stub













                    updateInstantAppInstallerLocked(packageName);















                }















            }













            ApplicationPackageManager.invalidateGetPackagesForUidCache();















        }





























        if (res) {