diff options
Diffstat (limited to 'debian/patches/0024-libports-use-protected-payloads-to-optimize-the-obje.patch')
| -rw-r--r-- | debian/patches/0024-libports-use-protected-payloads-to-optimize-the-obje.patch | 372 |
1 files changed, 0 insertions, 372 deletions
diff --git a/debian/patches/0024-libports-use-protected-payloads-to-optimize-the-obje.patch b/debian/patches/0024-libports-use-protected-payloads-to-optimize-the-obje.patch deleted file mode 100644 index 8d011c67..00000000 --- a/debian/patches/0024-libports-use-protected-payloads-to-optimize-the-obje.patch +++ /dev/null @@ -1,372 +0,0 @@ -From 0d11603df6f4c27570fd060870da666deca92af8 Mon Sep 17 00:00:00 2001 -From: Justus Winter <4winter@informatik.uni-hamburg.de> -Date: Sat, 23 Nov 2013 16:12:55 +0100 -Subject: [PATCH hurd 24/30] libports: use protected payloads to optimize the - object lookup - -* libports/create-internal.c (_ports_create_port_internal): Set the - protected payload to the objects address. -* libports/import-port.c (ports_import_port): Likewise. -* libports/reallocate-from-external.c (ports_reallocate_from_external): - Likewise. -* libports/reallocate-port.c (ports_reallocate_port): Likewise. -* libports/transfer-right.c (ports_transfer_right): Likewise. -* libports/manage-multithread.c (ports_manage_port_operations_multithread): - Use the protected payload as the objects address if provided. -* libports/manage-one-thread.c (ports_manage_port_operations_one_thread): - Likewise. ---- - libports/complete-deallocate.c | 7 +- - libports/create-internal.c | 5 +- - libports/destroy-right.c | 150 +++++++++++++++++++++++++++++++++++- - libports/import-port.c | 5 +- - libports/manage-multithread.c | 22 +++++- - libports/manage-one-thread.c | 22 +++++- - libports/reallocate-from-external.c | 3 + - libports/reallocate-port.c | 3 + - libports/transfer-right.c | 2 + - 9 files changed, 210 insertions(+), 9 deletions(-) - -diff --git a/libports/complete-deallocate.c b/libports/complete-deallocate.c -index 0d852f5..1a6eb54 100644 ---- a/libports/complete-deallocate.c -+++ b/libports/complete-deallocate.c -@@ -45,8 +45,11 @@ _ports_complete_deallocate (struct port_info *pi) - hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry); - pthread_rwlock_unlock (&_ports_htable_lock); - -- mach_port_mod_refs (mach_task_self (), pi->port_right, -- MACH_PORT_RIGHT_RECEIVE, -1); -+ /* If the right has been destroyed using ports_destroy_right, -+ port_right is set to MACH_PORT_DEAD. */ -+ if (MACH_PORT_VALID (pi->port_right)) -+ mach_port_mod_refs (mach_task_self (), pi->port_right, -+ MACH_PORT_RIGHT_RECEIVE, -1); - pi->port_right = MACH_PORT_NULL; - } - -diff --git a/libports/create-internal.c b/libports/create-internal.c -index 2d85931..2a1f504 100644 ---- a/libports/create-internal.c -+++ b/libports/create-internal.c -@@ -99,7 +99,10 @@ _ports_create_port_internal (struct port_class *class, - bucket->count++; - class->count++; - pthread_mutex_unlock (&_ports_lock); -- -+ -+ /* This is an optimization. It may fail. */ -+ mach_port_set_protected_payload (mach_task_self (), port, pi); -+ - if (install) - { - err = mach_port_move_member (mach_task_self (), pi->port_right, -diff --git a/libports/destroy-right.c b/libports/destroy-right.c -index 448b379..1e32379 100644 ---- a/libports/destroy-right.c -+++ b/libports/destroy-right.c -@@ -1,5 +1,5 @@ - /* -- Copyright (C) 1995, 1996, 1999 Free Software Foundation, Inc. -+ Copyright (C) 1995, 1996, 1999, 2014 Free Software Foundation, Inc. - Written by Michael I. Bushnell. - - This file is part of the GNU Hurd. -@@ -22,14 +22,26 @@ - #include <hurd/ihash.h> - #include <assert.h> - -+#include <pthread.h> -+#include <error.h> -+#include <time.h> -+ -+/* To prevent protected payloads from becoming stale, we defer the -+ derefercing of port_info objects. */ -+static error_t defer_dereferencing (struct port_info *pi); -+ - error_t - ports_destroy_right (void *portstruct) - { - struct port_info *pi = portstruct; - error_t err; - -+ pthread_mutex_lock (&_ports_lock); - if (pi->port_right != MACH_PORT_NULL) - { -+ mach_port_clear_protected_payload (mach_task_self (), -+ pi->port_right); -+ - pthread_rwlock_wrlock (&_ports_htable_lock); - hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry); - hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry); -@@ -42,10 +54,142 @@ ports_destroy_right (void *portstruct) - - if (pi->flags & PORT_HAS_SENDRIGHTS) - { -- pi->flags &= ~PORT_HAS_SENDRIGHTS; -- ports_port_deref (pi); -+ /* There are outstanding send rights, so we might get a -+ no-senders notification. Attached to the notification -+ is a reference to the port_info object. Of course we -+ destroyed the receive right these were send to above, but -+ the message could already have been send and dequeued. -+ -+ Previously, those messages would have carried an stale -+ name, which would have caused a hash table lookup -+ failure. However, stale payloads results in port_info -+ use-after-free. Therefore, we cannot release the -+ reference here, but defer that instead. */ -+ defer_dereferencing (pi); -+ } -+ else -+ hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry); -+ -+ pi->port_right = MACH_PORT_DEAD; -+ } -+ pthread_mutex_unlock (&_ports_lock); -+ -+ return 0; -+} -+ -+/* Simple lock-less generational garbage collection. */ -+ -+/* We maintain three lists of objects. Producers add objects to the -+ current generation G using defer_dereferencing. G-1 holds old -+ objects, G-2 holds garbage. */ -+static struct deferred_dereference -+{ -+ struct deferred_dereference *next; -+ struct port_info *pi; /* We hold a reference for these objects. */ -+} *generations[3]; /* Must be accessed using atomic -+ operations. */ -+ -+/* The current generation. Must be accessed using atomic operations. */ -+static int generation; -+ -+/* The garbage collection thread. Does not return. */ -+static void * -+gc_loop (void *arg) -+{ -+ while (1) -+ { -+ int old, garbage; -+ struct deferred_dereference *d; -+ -+ sleep (5); -+ -+ /* We are the only one updating generation, so this is safe. */ -+ old = generation; -+ -+ /* Update generation. */ -+ __atomic_store_n (&generation, (old + 1) % 3, __ATOMIC_RELAXED); -+ -+ /* This is the garbage generation. As all writers are long -+ gone, we do not need to bother with atomic operations. */ -+ garbage = (old + 2) % 3; -+ d = generations[garbage]; -+ generations[garbage] = NULL; -+ while (d != NULL) -+ { -+ struct deferred_dereference *next = d->next; -+ int references; -+ -+ pthread_mutex_lock (&_ports_lock); -+ references = d->pi->refcnt; -+ pthread_mutex_unlock (&_ports_lock); -+ -+ assert (references <= 2 || !"reference to destroyed right leaked"); -+ -+ if (references == 2) -+ { -+ /* Get rid of the hash table reference. */ -+ pthread_mutex_lock (&_ports_lock); -+ hurd_ihash_locp_remove (&d->pi->bucket->htable, d->pi->hentry); -+ pthread_mutex_unlock (&_ports_lock); -+ ports_port_deref (d->pi); -+ } -+ -+ /* Get rid of our reference. */ -+ ports_port_deref (d->pi); -+ -+ free (d); -+ d = next; - } - } - -+ assert (! "reached"); -+ return NULL; -+} -+ -+/* Start the gc thread. */ -+static void -+start_gc (void) -+{ -+ error_t err; -+ pthread_attr_t attr; -+ pthread_t thread; -+ -+ pthread_attr_init (&attr); -+#define STACK_SIZE (64 * 1024) -+ pthread_attr_setstacksize (&attr, STACK_SIZE); -+#undef STACK_SIZE -+ -+ err = pthread_create (&thread, &attr, gc_loop, NULL); -+ assert_perror (err); -+ err = pthread_detach (thread); -+ assert_perror (err); -+} -+ -+/* Defer the derefercing of port_info objects. */ -+static error_t -+defer_dereferencing (struct port_info *pi) -+{ -+ static pthread_once_t once = PTHREAD_ONCE_INIT; -+ int g; -+ struct deferred_dereference *d = malloc (sizeof *d); -+ if (d == NULL) -+ return ENOMEM; -+ -+ pthread_once (&once, start_gc); -+ -+ /* XXX we hold _ports_lock, so we cannot do -+ ports_port_ref (pi); */ -+ pi->refcnt += 1; -+ d->pi = pi; -+ -+ /* Append to the current generation. */ -+ g = __atomic_load_n (&generation, __ATOMIC_RELAXED); -+ -+ retry: -+ d->next = __atomic_load_n (&generations[g], __ATOMIC_RELAXED); -+ if (! __atomic_compare_exchange_n (&generations[g], &d->next, d, -+ 0, __ATOMIC_RELAXED, __ATOMIC_RELAXED)) -+ goto retry; -+ - return 0; - } -diff --git a/libports/import-port.c b/libports/import-port.c -index c337c85..f24f3e0 100644 ---- a/libports/import-port.c -+++ b/libports/import-port.c -@@ -93,7 +93,10 @@ ports_import_port (struct port_class *class, struct port_bucket *bucket, - bucket->count++; - class->count++; - pthread_mutex_unlock (&_ports_lock); -- -+ -+ /* This is an optimization. It may fail. */ -+ mach_port_set_protected_payload (mach_task_self (), port, pi); -+ - mach_port_move_member (mach_task_self (), port, bucket->portset); - - if (stat.mps_srights) -diff --git a/libports/manage-multithread.c b/libports/manage-multithread.c -index 2067cba..90b3044 100644 ---- a/libports/manage-multithread.c -+++ b/libports/manage-multithread.c -@@ -162,7 +162,27 @@ ports_manage_port_operations_multithread (struct port_bucket *bucket, - outp->RetCodeType = RetCodeType; - outp->RetCode = MIG_BAD_ID; - -- pi = ports_lookup_port (bucket, inp->msgh_local_port, 0); -+ if (MACH_MSGH_BITS_LOCAL (inp->msgh_bits) == -+ MACH_MSG_TYPE_PROTECTED_PAYLOAD) -+ { -+ pi = (struct port_info *) inp->msgh_protected_payload; -+ if (pi && pi->bucket == bucket) -+ ports_port_ref (pi); -+ else -+ pi = NULL; -+ } -+ else -+ { -+ pi = ports_lookup_port (bucket, inp->msgh_local_port, 0); -+ if (pi) -+ { -+ inp->msgh_bits = MACH_MSGH_BITS ( -+ MACH_MSGH_BITS_REMOTE (inp->msgh_bits), -+ MACH_MSG_TYPE_PROTECTED_PAYLOAD); -+ inp->msgh_protected_payload = (unsigned long) pi; -+ } -+ } -+ - if (pi) - { - error_t err = ports_begin_rpc (pi, inp->msgh_id, &link); -diff --git a/libports/manage-one-thread.c b/libports/manage-one-thread.c -index cbd2df7..58c0f36 100644 ---- a/libports/manage-one-thread.c -+++ b/libports/manage-one-thread.c -@@ -57,7 +57,27 @@ ports_manage_port_operations_one_thread (struct port_bucket *bucket, - outp->RetCodeType = RetCodeType; - outp->RetCode = MIG_BAD_ID; - -- pi = ports_lookup_port (bucket, inp->msgh_local_port, 0); -+ if (MACH_MSGH_BITS_LOCAL (inp->msgh_bits) == -+ MACH_MSG_TYPE_PROTECTED_PAYLOAD) -+ { -+ pi = (struct port_info *) inp->msgh_protected_payload; -+ if (pi && pi->bucket == bucket) -+ ports_port_ref (pi); -+ else -+ pi = NULL; -+ } -+ else -+ { -+ pi = ports_lookup_port (bucket, inp->msgh_local_port, 0); -+ if (pi) -+ { -+ inp->msgh_bits = MACH_MSGH_BITS ( -+ MACH_MSGH_BITS_REMOTE (inp->msgh_bits), -+ MACH_MSG_TYPE_PROTECTED_PAYLOAD); -+ inp->msgh_protected_payload = (unsigned long) pi; -+ } -+ } -+ - if (pi) - { - err = ports_begin_rpc (pi, inp->msgh_id, &link); -diff --git a/libports/reallocate-from-external.c b/libports/reallocate-from-external.c -index 7205bd9..f83419c 100644 ---- a/libports/reallocate-from-external.c -+++ b/libports/reallocate-from-external.c -@@ -71,6 +71,9 @@ ports_reallocate_from_external (void *portstruct, mach_port_t receive) - pthread_mutex_unlock (&_ports_lock); - assert_perror (err); - -+ /* This is an optimization. It may fail. */ -+ mach_port_set_protected_payload (mach_task_self (), pi->port_right, pi); -+ - mach_port_move_member (mach_task_self (), receive, pi->bucket->portset); - - if (stat.mps_srights) -diff --git a/libports/reallocate-port.c b/libports/reallocate-port.c -index cc534eb..7ae345b 100644 ---- a/libports/reallocate-port.c -+++ b/libports/reallocate-port.c -@@ -59,6 +59,9 @@ ports_reallocate_port (void *portstruct) - pthread_mutex_unlock (&_ports_lock); - assert_perror (err); - -+ /* This is an optimization. It may fail. */ -+ mach_port_set_protected_payload (mach_task_self (), pi->port_right, pi); -+ - err = mach_port_move_member (mach_task_self (), pi->port_right, - pi->bucket->portset); - assert_perror (err); -diff --git a/libports/transfer-right.c b/libports/transfer-right.c -index 776a8d2..31e3b2f 100644 ---- a/libports/transfer-right.c -+++ b/libports/transfer-right.c -@@ -91,6 +91,8 @@ ports_transfer_right (void *tostruct, - err = hurd_ihash_add (&topi->bucket->htable, port, topi); - pthread_rwlock_unlock (&_ports_htable_lock); - assert_perror (err); -+ /* This is an optimization. It may fail. */ -+ mach_port_set_protected_payload (mach_task_self (), port, topi); - if (topi->bucket != frompi->bucket) - { - err = mach_port_move_member (mach_task_self (), port, --- -2.1.3 - |