diff options
Diffstat (limited to 'debian')
| -rw-r--r-- | debian/patches/libpager-threading-rework.patch | 1983 | ||||
| -rw-r--r-- | debian/patches/series | 1 |
2 files changed, 0 insertions, 1984 deletions
diff --git a/debian/patches/libpager-threading-rework.patch b/debian/patches/libpager-threading-rework.patch deleted file mode 100644 index 2b8c1ac6..00000000 --- a/debian/patches/libpager-threading-rework.patch +++ /dev/null @@ -1,1983 +0,0 @@ -commit be7319c2857598f36545cf31addfb8e35f56834d -Author: Justus Winter <4winter@informatik.uni-hamburg.de> -Date: Thu Apr 17 15:44:12 2014 +0200 - - libpager: rework the request handling to use less threads - - Previously, libpager used multiple threads to receive messages from - the pager bucket. It used sequence barriers to execute the requests - to order requests to each object. - - The sequence barriers are implemented in seqnos.c. A server function - uses _pager_wait_for_seqno to wait for its sequence number and - _pager_release_seqno to release it, or it uses _pager_update_seqno to - do both operations in one step. - - These sequence barriers divide each server function in three parts: A, - B, and C. A_i happens "before" the sequence barrier i, B_i happens - "in order", C_i happens "after" the sequence barrier. This partial - order < has the following properties: - - * This order is *per object*. Requests to different objects are not - ordered. - - * A_i < B_i, B_i < C_i (due to the structure of the code) - - * B_i < B_{i+1} (this is due to the sequence barriers) - - * Note that only the B parts are ordered by the sequence numbers, we - are free to execute C_i and C_{i+1} in any possible order. The same - argument applies to the A parts. - - If the server functions would never to block, a single threaded could - do the job. Unfortunately, we sometimes call user-supplied functions - like pager_write_pager, which may block for some time doing IO. - Worse, ext2fs used to trigger a page fault during pager_write_pager, - creating yet another request to the disk pager (and thus, libpager). - - Surveying the code revealed that most of the server functions only - validate arguments in their A phase, do some non-blocking work in - their B phase and then send the reply in their C phase. Three - functions, however, do some potentially blocking and otherwise bad - behaving stuff in their C phase. The three interesting functions are - _pager_seqnos_memory_object_data_request, - _pager_seqnos_memory_object_data_return, and quest. Most notably, the - first calls pager_read_page and the second pager_write_page. - - The sequence barriers are implemented using a very simple ticket - algorithm. Every request, even the invalid ones, is processed by a - thread, and waits until the ticket count reaches its seqno, does some - work in-order, then increments the ticket and awakes all threads that - have piled up up to this moment. All of them except one will then - discover that it's not their turn yet and go to sleep again. - - Creating one thread per request has proven to be problematic as - memory_object requests often arrive in large batches. - - This patch does four things: - - * Use a single thread to receive messages from the port bucket. All - incoming request are put into a queue. - - * Use a fixed-number of threads (though even one is actually enough) - to execute the A and B parts of the server functions. If multiple - threads are used, a work-delegation mechanism ensures that the per - object order < is observed. See the comments in demuxer.c for a - more detailed description and why having a small number of threads - (I propose 3) is advantageous. - - * The code from the C parts is moved out of the server function X into - X_deferred. An "interesting" function now puts a deferred function - calls into a queue instead of executing that part directly. - - * A variable number of threads (though this number is kept close to - one) is executing deferred functions from the queue of deferred - functions. As memory_object requests often arrive in large batches, - the key insight here is to rate-limit the creation of threads. See - the comments in deferreds.c for details on the implementation and - why a lower number of threads results in a better performance. - - For reference, I used the following command to create workloads that - highlight the problem this patch is addressing: - - % settrans t .../ext2fs --sync=30 /dev/sd2s1 - ... - % /usr/bin/time zsh -c 'for ((i=0; i < 3500; i++)); do - dd if=/dev/zero of=t/src/$i bs=4k count=290 2>/dev/null - echo -n . - if ((i % 100 == 0)) ; then echo -n $i; fi - done' - - With this patch, the number of libpager threads tops at 12, and it is - just 6 most of the time. - - * libpager/deferreds.c: New file. - * libpager/deferreds.h: Likewise. - * libpager/pool.c: Likewise. - * libpager/pool.h: Likewise. - * libpager/queue.h: Likewise. - * libpager/demuxer.c: Manage a queue of requests received from the - port bucket. - (pager_demuxer): Just decode the server function and enqueue the - request. - (worker_func): New function that consumes and executes the requests - from the queue. - (service_paging_requests): New function. - (pager_start_workers): Likewise. - * libpager/data-request.c: Remove the seqno barriers. Move code from - the 'C' phase into a deferred function. - * libpager/data-return.c: Likewise. - * libpager/data-unlock.c: Likewise. - * libpager/chg-compl.c: Remove the seqno barriers. - * libpager/lock-completed.c: Likewise. - * libpager/no-senders.c: Likewise. - * libpager/notify-stubs.c: Likewise. - * libpager/object-init.c: Likewise. - * libpager/object-terminate.c: Likewise. - * libpager/seqnos.c: Remove file. - * libpager/stubs.c: Likewise. - * libpager/pager.h (pager_demuxer): Drop declaration. - (pager_start_workers): New declaration. - * libpager/priv.h: Remove the _pager_seqno declarations. - * libpager/Makefile (SRCS): Drop seqnos.c, add deferreds.c, pool.c. - * console/pager.c (user_pager_init): Call pager_start_workers. - * libdiskfs/disk-pager.c: Likewise. - * storeio/pager.c: Likewise. - -diff --git a/console/pager.c b/console/pager.c -index 87c36f0..a08e46d 100644 ---- a/console/pager.c -+++ b/console/pager.c -@@ -119,22 +119,6 @@ void - pager_dropweak (struct user_pager_info *upi) - { - } -- -- --/* A top-level function for the paging thread that just services paging -- requests. */ --static void * --service_paging_requests (void *arg) --{ -- struct port_bucket *pager_bucket = arg; -- for (;;) -- ports_manage_port_operations_multithread (pager_bucket, -- pager_demuxer, -- 1000 * 60 * 2, -- 1000 * 60 * 10, 0); -- return NULL; --} -- - - /* Initialize the pager for the display component. */ - void -@@ -148,15 +132,10 @@ user_pager_init (void) - if (! pager_bucket) - error (5, errno, "Cannot create pager bucket"); - -- /* Make a thread to service paging requests. */ -- err = pthread_create (&thread, NULL, service_paging_requests, pager_bucket); -- if (!err) -- pthread_detach (thread); -- else -- { -- errno = err; -- perror ("pthread_create"); -- } -+ /* Start libpagers worker thread. */ -+ err = pager_start_workers (pager_bucket); -+ if (err) -+ error (5, err, "Cannot start pager worker threads"); - } - - -diff --git a/libdiskfs/disk-pager.c b/libdiskfs/disk-pager.c -index 9a0d9d8..eb309b1 100644 ---- a/libdiskfs/disk-pager.c -+++ b/libdiskfs/disk-pager.c -@@ -33,39 +33,19 @@ static struct hurd_signal_preemptor preemptor = - handler: (sighandler_t) &fault_handler, - }; - --/* A top-level function for the paging thread that just services paging -- requests. */ --static void * --service_paging_requests (void *arg) --{ -- struct port_bucket *pager_bucket = arg; -- for (;;) -- ports_manage_port_operations_multithread (pager_bucket, -- pager_demuxer, -- 1000 * 60 * 2, -- 1000 * 60 * 10, 0); -- return NULL; --} -- - void - diskfs_start_disk_pager (struct user_pager_info *upi, - struct port_bucket *pager_bucket, - int may_cache, int notify_on_evict, - size_t size, void **image) - { -- pthread_t thread; - error_t err; - mach_port_t disk_pager_port; - -- /* Make a thread to service paging requests. */ -- err = pthread_create (&thread, NULL, service_paging_requests, pager_bucket); -- if (!err) -- pthread_detach (thread); -- else -- { -- errno = err; -- perror ("pthread_create"); -- } -+ /* Start libpagers worker thread. */ -+ err = pager_start_workers (pager_bucket); -+ if (err) -+ error (2, err, "creating pager worker threads failed"); - - /* Create the pager. */ - diskfs_disk_pager = pager_create (upi, pager_bucket, -diff --git a/libpager/Makefile b/libpager/Makefile -index b622295..6e7f43f 100644 ---- a/libpager/Makefile -+++ b/libpager/Makefile -@@ -22,9 +22,9 @@ SRCS = data-request.c data-return.c data-unlock.c pager-port.c \ - inhibit-term.c lock-completed.c lock-object.c mark-error.c \ - no-senders.c object-init.c object-terminate.c pagemap.c \ - pager-create.c pager-flush.c pager-shutdown.c pager-sync.c \ -- stubs.c seqnos.c demuxer.c chg-compl.c pager-attr.c clean.c \ -+ stubs.c demuxer.c chg-compl.c pager-attr.c clean.c \ - dropweak.c notify-stubs.c get-upi.c pager-memcpy.c pager-return.c \ -- offer-page.c -+ offer-page.c deferreds.c pool.c - installhdrs = pager.h - - HURDLIBS= ports -diff --git a/libpager/chg-compl.c b/libpager/chg-compl.c -index d77c46c..89ccfc8 100644 ---- a/libpager/chg-compl.c -+++ b/libpager/chg-compl.c -@@ -37,7 +37,6 @@ _pager_seqnos_memory_object_change_completed (struct pager *p, - } - - pthread_mutex_lock (&p->interlock); -- _pager_wait_for_seqno (p, seq); - - for (ar = p->attribute_requests; ar; ar = ar->next) - if (ar->may_cache == maycache && ar->copy_strategy == strat) -@@ -46,8 +45,7 @@ _pager_seqnos_memory_object_change_completed (struct pager *p, - pthread_cond_broadcast (&p->wakeup); - break; - } -- -- _pager_release_seqno (p, seq); -+ - pthread_mutex_unlock (&p->interlock); - return 0; - } -diff --git a/libpager/data-request.c b/libpager/data-request.c -index 82ce904..0bceac4 100644 ---- a/libpager/data-request.c -+++ b/libpager/data-request.c -@@ -15,11 +15,21 @@ - along with this program; if not, write to the Free Software - Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ - -+#include "deferreds.h" - #include "priv.h" - #include "memory_object_S.h" - #include <stdio.h> - #include <string.h> - -+static void memory_object_data_request_deferred (void *arg); -+ -+struct deferred_args -+{ -+ struct pager *p; -+ vm_offset_t offset; -+ vm_size_t length; -+}; -+ - /* Implement pagein callback as described in <mach/memory_object.defs>. */ - kern_return_t - _pager_seqnos_memory_object_data_request (struct pager *p, -@@ -31,9 +41,8 @@ _pager_seqnos_memory_object_data_request (struct pager *p, - { - short *pm_entry; - int doread, doerror; -+ struct deferred_args *deferred; - error_t err; -- vm_address_t page; -- int write_lock; - - if (!p - || p->port.class != _pager_class) -@@ -41,7 +50,6 @@ _pager_seqnos_memory_object_data_request (struct pager *p, - - /* Acquire the right to meddle with the pagemap */ - pthread_mutex_lock (&p->interlock); -- _pager_wait_for_seqno (p, seqno); - - /* sanity checks -- we don't do multi-page requests yet. */ - if (control != p->memobjcntl) -@@ -105,7 +113,6 @@ _pager_seqnos_memory_object_data_request (struct pager *p, - } - - /* Let someone else in. */ -- _pager_release_seqno (p, seqno); - pthread_mutex_unlock (&p->interlock); - - if (!doread) -@@ -113,18 +120,16 @@ _pager_seqnos_memory_object_data_request (struct pager *p, - if (doerror) - goto error_read; - -- err = pager_read_page (p->upi, offset, &page, &write_lock); -- if (err) -- goto error_read; -+ deferred = _pager_allocate_deferred (memory_object_data_request_deferred, -+ sizeof *deferred); -+ if (deferred == NULL) -+ return ENOMEM; - -- memory_object_data_supply (p->memobjcntl, offset, page, length, 1, -- write_lock ? VM_PROT_WRITE : VM_PROT_NONE, -- p->notify_on_evict ? 1 : 0, -- MACH_PORT_NULL); -- pthread_mutex_lock (&p->interlock); -- _pager_mark_object_error (p, offset, length, 0); -- _pager_allow_termination (p); -- pthread_mutex_unlock (&p->interlock); -+ ports_port_ref (p); -+ deferred->p = p; -+ deferred->offset = offset; -+ deferred->length = length; -+ _pager_defer (deferred); - return 0; - - error_read: -@@ -139,7 +144,41 @@ _pager_seqnos_memory_object_data_request (struct pager *p, - allow_release_out: - _pager_allow_termination (p); - release_out: -- _pager_release_seqno (p, seqno); - pthread_mutex_unlock (&p->interlock); - return 0; - } -+ -+static void -+memory_object_data_request_deferred (void *arg) -+{ -+ struct deferred_args *args = arg; -+ vm_address_t page; -+ int write_lock; -+ error_t err; -+ -+ err = pager_read_page (args->p->upi, args->offset, &page, &write_lock); -+ if (err) -+ { -+ memory_object_data_error (args->p->memobjcntl, args->offset, -+ args->length, EIO); -+ _pager_mark_object_error (args->p, args->offset, args->length, EIO); -+ -+ pthread_mutex_lock (&args->p->interlock); -+ _pager_allow_termination (args->p); -+ pthread_mutex_unlock (&args->p->interlock); -+ goto out; -+ } -+ -+ memory_object_data_supply (args->p->memobjcntl, args->offset, page, -+ args->length, 1, -+ write_lock ? VM_PROT_WRITE : VM_PROT_NONE, -+ args->p->notify_on_evict ? 1 : 0, -+ MACH_PORT_NULL); -+ pthread_mutex_lock (&args->p->interlock); -+ _pager_mark_object_error (args->p, args->offset, args->length, 0); -+ _pager_allow_termination (args->p); -+ pthread_mutex_unlock (&args->p->interlock); -+ -+ out: -+ ports_port_deref (args->p); -+} -diff --git a/libpager/data-return.c b/libpager/data-return.c -index ee6c6e8..70c2cc8 100644 ---- a/libpager/data-return.c -+++ b/libpager/data-return.c -@@ -15,12 +15,36 @@ - along with this program; if not, write to the Free Software - Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ - -+#include "deferreds.h" - #include "priv.h" - #include "memory_object_S.h" - #include <stdio.h> - #include <string.h> - #include <assert.h> - -+static void memory_object_data_return_deferred (void *arg); -+ -+struct lock_list -+{ -+ struct lock_request *lr; -+ struct lock_list *next; -+}; -+ -+struct deferred_args -+{ -+ struct pager *p; -+ vm_offset_t offset; -+ pointer_t data; -+ vm_size_t length; -+ int kcopy; -+ int npages; -+ char *notified; -+ error_t *pagerrs; -+ struct lock_list *lock_list; -+ int omitdata; -+}; -+ -+ - /* Worker function used by _pager_seqnos_memory_object_data_return - and _pager_seqnos_memory_object_data_initialize. All args are - as for _pager_seqnos_memory_object_data_return; the additional -@@ -38,13 +62,13 @@ _pager_do_write_request (struct pager *p, - { - short *pm_entries; - int npages, i; -- char *notified; -- error_t *pagerrs; -+ char *notified = NULL; -+ error_t *pagerrs = NULL; - struct lock_request *lr; -- struct lock_list {struct lock_request *lr; -- struct lock_list *next;} *lock_list, *ll; -- int wakeup; -+ struct lock_list *lock_list = NULL, *ll; - int omitdata = 0; -+ struct deferred_args *deferred; -+ error_t err; - - if (!p - || p->port.class != _pager_class) -@@ -52,7 +76,6 @@ _pager_do_write_request (struct pager *p, - - /* Acquire the right to meddle with the pagemap */ - pthread_mutex_lock (&p->interlock); -- _pager_wait_for_seqno (p, seqno); - - /* sanity checks -- we don't do multi-page requests yet. */ - if (control != p->memobjcntl) -@@ -78,9 +101,9 @@ _pager_do_write_request (struct pager *p, - } - - npages = length / __vm_page_size; -- pagerrs = alloca (npages * sizeof (error_t)); -+ pagerrs = malloc (npages * sizeof (error_t)); - -- notified = alloca (npages * (sizeof *notified)); -+ notified = malloc (npages * (sizeof *notified)); - #ifndef NDEBUG - memset (notified, -1, npages * (sizeof *notified)); - #endif -@@ -101,7 +124,6 @@ _pager_do_write_request (struct pager *p, - notified[i] = (p->notify_on_evict - && ! (pm_entries[i] & PM_PAGEINWAIT)); - -- _pager_release_seqno (p, seqno); - goto notify; - } - else { -@@ -150,7 +172,7 @@ _pager_do_write_request (struct pager *p, - for (lr = p->lock_requests; lr; lr = lr->next) - if (offset < lr->end && offset + length >= lr->start) - { -- ll = alloca (sizeof (struct lock_list)); -+ ll = malloc (sizeof (struct lock_list)); - ll->lr = lr; - ll->next = lock_list; - lock_list = ll; -@@ -158,36 +180,106 @@ _pager_do_write_request (struct pager *p, - } - - /* Let someone else in. */ -- _pager_release_seqno (p, seqno); - pthread_mutex_unlock (&p->interlock); - -+ deferred = _pager_allocate_deferred (memory_object_data_return_deferred, -+ sizeof *deferred); -+ if (deferred == NULL) -+ { -+ err = ENOMEM; -+ goto release_mem; -+ } -+ -+ ports_port_ref (p); -+ deferred->p = p; -+ deferred->offset = offset; -+ deferred->data = data; -+ deferred->length = length; -+ deferred->kcopy = kcopy; -+ deferred->npages = npages; -+ deferred->notified = notified; -+ deferred->pagerrs = pagerrs; -+ deferred->lock_list = lock_list; -+ deferred->omitdata = omitdata; -+ _pager_defer (deferred); -+ return 0; -+ -+ notify: -+ _pager_allow_termination (p); -+ pthread_mutex_unlock (&p->interlock); -+ -+ for (i = 0; i < npages; i++) -+ { -+ assert (notified[i] == 0 || notified[i] == 1); -+ if (notified[i]) -+ { -+ short *pm_entry = &pm_entries[i]; -+ -+ /* Do notify user. */ -+ pager_notify_evict (p->upi, offset + (i * vm_page_size)); -+ -+ /* Clear any error that is left. Notification on eviction -+ is used only to change association of page, so any -+ error may no longer be valid. */ -+ pthread_mutex_lock (&p->interlock); -+ *pm_entry = SET_PM_ERROR (SET_PM_NEXTERROR (*pm_entry, 0), 0); -+ pthread_mutex_unlock (&p->interlock); -+ } -+ } -+ goto release_mem; -+ -+ release_out: -+ pthread_mutex_unlock (&p->interlock); -+ -+ release_mem: -+ free (notified); -+ free (pagerrs); -+ for (ll = lock_list; ll; /* nop */) -+ { -+ struct lock_list *o = ll; -+ ll = ll->next; -+ free (o); -+ } -+ -+ return err; -+} -+ -+static void -+memory_object_data_return_deferred (void *arg) -+{ -+ struct deferred_args *a = arg; -+ int i; -+ struct lock_list *ll; -+ short *pm_entries; -+ int wakeup; -+ - /* This is inefficient; we should send all the pages to the device at once - but until the pager library interface is changed, this will have to do. */ - -- for (i = 0; i < npages; i++) -- if (!(omitdata & (1 << i))) -- pagerrs[i] = pager_write_page (p->upi, -- offset + (vm_page_size * i), -- data + (vm_page_size * i)); -+ for (i = 0; i < a->npages; i++) -+ if (!(a->omitdata & (1 << i))) -+ a->pagerrs[i] = pager_write_page (a->p->upi, -+ a->offset + (vm_page_size * i), -+ a->data + (vm_page_size * i)); - - /* Acquire the right to meddle with the pagemap */ -- pthread_mutex_lock (&p->interlock); -- _pager_pagemap_resize (p, offset + length); -- pm_entries = &p->pagemap[offset / __vm_page_size]; -+ pthread_mutex_lock (&a->p->interlock); -+ _pager_pagemap_resize (a->p, a->offset + a->length); -+ pm_entries = &a->p->pagemap[a->offset / __vm_page_size]; - - wakeup = 0; -- for (i = 0; i < npages; i++) -+ for (i = 0; i < a->npages; i++) - { -- if (omitdata & (1 << i)) -+ if (a->omitdata & (1 << i)) - { -- notified[i] = 0; -+ a->notified[i] = 0; - continue; - } - - if (pm_entries[i] & PM_WRITEWAIT) - wakeup = 1; - -- if (pagerrs[i] && ! (pm_entries[i] & PM_PAGEINWAIT)) -+ if (a->pagerrs[i] && ! (pm_entries[i] & PM_PAGEINWAIT)) - /* The only thing we can do here is mark the page, and give - errors from now on when it is to be read. This is - imperfect, because if all users go away, the pagemap will -@@ -199,61 +291,63 @@ _pager_do_write_request (struct pager *p, - - if (pm_entries[i] & PM_PAGEINWAIT) - { -- memory_object_data_supply (p->memobjcntl, -- offset + (vm_page_size * i), -- data + (vm_page_size * i), -+ memory_object_data_supply (a->p->memobjcntl, -+ a->offset + (vm_page_size * i), -+ a->data + (vm_page_size * i), - vm_page_size, 1, - VM_PROT_NONE, 0, MACH_PORT_NULL); -- notified[i] = 0; -+ a->notified[i] = 0; - } - else - { -- munmap ((void *) (data + (vm_page_size * i)), -+ munmap ((void *) (a->data + (vm_page_size * i)), - vm_page_size); -- notified[i] = (! kcopy && p->notify_on_evict); -- if (! kcopy) -+ a->notified[i] = (! a->kcopy && a->p->notify_on_evict); -+ if (! a->kcopy) - pm_entries[i] &= ~PM_INCORE; - } - - pm_entries[i] &= ~(PM_PAGINGOUT | PM_PAGEINWAIT | PM_WRITEWAIT); - } - -- for (ll = lock_list; ll; ll = ll->next) -+ for (ll = a->lock_list; ll; ll = ll->next) - if (!--ll->lr->pending_writes && !ll->lr->locks_pending) - wakeup = 1; - - if (wakeup) -- pthread_cond_broadcast (&p->wakeup); -+ pthread_cond_broadcast (&a->p->wakeup); - -- notify: -- _pager_allow_termination (p); -- pthread_mutex_unlock (&p->interlock); -+ _pager_allow_termination (a->p); -+ pthread_mutex_unlock (&a->p->interlock); - -- for (i = 0; i < npages; i++) -+ for (i = 0; i < a->npages; i++) - { -- assert (notified[i] == 0 || notified[i] == 1); -- if (notified[i]) -+ assert (a->notified[i] == 0 || a->notified[i] == 1); -+ if (a->notified[i]) - { - short *pm_entry = &pm_entries[i]; - - /* Do notify user. */ -- pager_notify_evict (p->upi, offset + (i * vm_page_size)); -+ pager_notify_evict (a->p->upi, a->offset + (i * vm_page_size)); - - /* Clear any error that is left. Notification on eviction - is used only to change association of page, so any - error may no longer be valid. */ -- pthread_mutex_lock (&p->interlock); -+ pthread_mutex_lock (&a->p->interlock); - *pm_entry = SET_PM_ERROR (SET_PM_NEXTERROR (*pm_entry, 0), 0); -- pthread_mutex_unlock (&p->interlock); -+ pthread_mutex_unlock (&a->p->interlock); - } - } - -- return 0; -- -- release_out: -- _pager_release_seqno (p, seqno); -- pthread_mutex_unlock (&p->interlock); -- return 0; -+ free (a->notified); -+ free (a->pagerrs); -+ for (ll = a->lock_list; ll; /* nop */) -+ { -+ struct lock_list *o = ll; -+ ll = ll->next; -+ free (o); -+ } -+ ports_port_deref (a->p); - } - - /* Implement pageout call back as described by <mach/memory_object.defs>. */ -diff --git a/libpager/data-unlock.c b/libpager/data-unlock.c -index 599237c..a969ca6 100644 ---- a/libpager/data-unlock.c -+++ b/libpager/data-unlock.c -@@ -15,9 +15,21 @@ - along with this program; if not, write to the Free Software - Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ - -+#include "deferreds.h" - #include "priv.h" - #include "memory_object_S.h" - #include <stdio.h> -+#include <stdlib.h> -+#include <error.h> -+ -+static void memory_object_data_unlock_deferred (void *arg); -+ -+struct deferred_args -+{ -+ struct pager *p; -+ vm_offset_t offset; -+ vm_size_t length; -+}; - - /* Implement kernel requests for access as described in - <mach/memory_object.defs>. */ -@@ -29,17 +41,13 @@ _pager_seqnos_memory_object_data_unlock (struct pager *p, - vm_size_t length, - vm_prot_t access) - { -- volatile int err; -+ error_t err = 0; -+ struct deferred_args *deferred; - - if (!p - || p->port.class != _pager_class) - return EOPNOTSUPP; - -- pthread_mutex_lock (&p->interlock); -- _pager_wait_for_seqno (p, seqno); -- _pager_release_seqno (p, seqno); -- pthread_mutex_unlock (&p->interlock); -- - if (p->pager_state != NORMAL) - { - printf ("pager in wrong state for unlock\n"); -@@ -68,20 +76,45 @@ _pager_seqnos_memory_object_data_unlock (struct pager *p, - goto out; - } - -- err = pager_unlock_page (p->upi, offset); -+ deferred = _pager_allocate_deferred (memory_object_data_unlock_deferred, -+ sizeof *deferred); -+ if (deferred == NULL) -+ { -+ err = ENOMEM; -+ goto out; -+ } -+ -+ ports_port_ref (p); -+ deferred->p = p; -+ deferred->offset = offset; -+ deferred->length = length; -+ _pager_defer (deferred); - -+ out: -+ return err; -+} -+ -+static void -+memory_object_data_unlock_deferred (void *arg) -+{ -+ struct deferred_args *args = arg; -+ -+ error_t err = pager_unlock_page (args->p->upi, args->offset); - if (!err) - /* We can go ahead and release the lock. */ -- _pager_lock_object (p, offset, length, MEMORY_OBJECT_RETURN_NONE, 0, -- VM_PROT_NONE, 0); -+ _pager_lock_object (args->p, args->offset, args->length, -+ MEMORY_OBJECT_RETURN_NONE, 0, -+ VM_PROT_NONE, 0); - else - { - /* Flush the page, and set a bit so that m_o_data_request knows -- to issue an error. */ -- _pager_lock_object (p, offset, length, MEMORY_OBJECT_RETURN_NONE, 1, -- VM_PROT_WRITE, 1); -- _pager_mark_next_request_error (p, offset, length, err); -+ to issue an error. */ -+ _pager_lock_object (args->p, args->offset, args->length, -+ MEMORY_OBJECT_RETURN_NONE, 1, -+ VM_PROT_WRITE, 1); -+ _pager_mark_next_request_error (args->p, args->offset, args->length, -+ err); - } -- out: -- return 0; -+ -+ ports_port_deref (args->p); - } -diff --git a/libpager/deferreds.c b/libpager/deferreds.c -new file mode 100644 -index 0000000..25f2420 ---- /dev/null -+++ b/libpager/deferreds.c -@@ -0,0 +1,246 @@ -+/* Deferred function queue. -+ -+ Copyright (C) 2014 Free Software Foundation, Inc. -+ -+ Written by Justus Winter <4winter@informatik.uni-hamburg.de> -+ -+ This file is part of the GNU Hurd. -+ -+ The GNU Hurd is free software; you can redistribute it and/or -+ modify it under the terms of the GNU General Public License as -+ published by the Free Software Foundation; either version 2, or (at -+ your option) any later version. -+ -+ The GNU Hurd is distributed in the hope that it will be useful, but -+ WITHOUT ANY WARRANTY; without even the implied warranty of -+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU -+ General Public License for more details. -+ -+ You should have received a copy of the GNU General Public License -+ along with the GNU Hurd. If not, see <http://www.gnu.org/licenses/>. */ -+ -+#include <error.h> -+#include <maptime.h> -+#include <pthread.h> -+#include <stddef.h> -+#include <stdlib.h> -+#include <sys/time.h> -+ -+#include "deferreds.h" -+#include "pool.h" -+#include "queue.h" -+ -+/* -+ Worker pool for the deferred functions. -+ -+ Server functions may offload long-running functions to a pool of -+ workers. In theory, a single thread would suffice to service this -+ pool. However, ext2fs complicates this quite a bit. -+ -+ ext2fs uses libpager to implement a disk cache and a file cache. If -+ ext2fs services a memory_object request to an object in the file -+ cache, it can trigger an additional request by dereferencing a -+ pointer to memory backed by the disk cache. -+ -+ This is most likely the reason for thread-storms (or rather, the -+ reason why thread storms are that bad). It needs to be addressed in -+ ext2fs. Until it is, we can reasonably well with a simple thread -+ pool that creates threads on demand but limits the rate of the -+ thread creation. -+ -+ Rate-limiting the thread creation is crucial as memory_object -+ requests often arrive in large batches. The rate-limiting is -+ implemented using the token bucket algorithm. -+ -+ Creating more than one worker thread potentially decreases -+ performance. The operations offloaded to this pool are typically IO -+ requests. Using only one thread to perform such operations will -+ likely result in a more linear access pattern. -+ -+ XXX perform some tests on real hardware -+ -+ The following parameters are chosen based on these observations: -+*/ -+ -+#define DEFERREDS_MIN_IDLE 1 /* Create threads on demand so -+ that there is always an -+ idle thread. */ -+#define DEFERREDS_MAX_IDLE 1 /* Keep at most one idle -+ thread around. */ -+#define DEFERREDS_TIMEOUT 1 /* Superfluous idle threads -+ exit after one second. */ -+/* XXX The next two values are somewhat magic but performed well. */ -+#define DEFERREDS_BUCKET_SIZE 3. /* Limit creation of threads -+ to three threads... */ -+#define DEFERREDS_BUCKET_PER 2. /* ... every two seconds. */ -+ -+/* Set to 1 to see messages about thread creation and destruction. */ -+#if 0 -+#define TRACE(ARGS...) error (0, 0, ARGS) -+#else -+#define TRACE(ARGS...) -+#endif -+ -+/* Mapped time as fast time source. */ -+static volatile struct mapped_time_value *mapped_time; -+ -+/* Queue and worker pool for the deferred functions. */ -+static struct -+{ -+ struct queue queue; -+ struct pool pool; -+ struct timeval last_check; -+ float bucket; -+ pthread_cond_t wakeup; -+ pthread_mutex_t lock; -+} deferreds; -+ -+/* A deferred is a deferred function call. */ -+struct deferred -+{ -+ struct item item; -+ deferred_function_t function; -+ char args[0]; -+}; -+ -+void * -+deferreds_worker_func (void *arg __attribute__ ((unused))) -+{ -+ int idle; -+ adjust_priority (pool_thread_online (&deferreds.pool)); -+ -+ while (1) -+ { -+ struct deferred *d; -+ error_t err; -+ struct timespec ts; -+ -+ pthread_mutex_lock (&deferreds.lock); -+ -+ while ((d = queue_dequeue (&deferreds.queue)) == NULL) -+ { -+ clock_gettime (CLOCK_REALTIME, &ts); -+ ts.tv_sec += DEFERREDS_TIMEOUT; -+ -+ pool_thread_idle (&deferreds.pool); -+ err = pthread_cond_timedwait (&deferreds.wakeup, &deferreds.lock, -+ &ts); -+ idle = pool_thread_busy (&deferreds.pool); -+ -+ if (err == ETIMEDOUT && idle >= DEFERREDS_MAX_IDLE) -+ goto out; -+ } -+ -+ pthread_mutex_unlock (&deferreds.lock); -+ -+ (*d->function) (&d->args); -+ free (d); -+ } -+ -+ out: -+ TRACE ("deferred worker thread exiting, %d idle workers left", idle); -+ pthread_mutex_unlock (&deferreds.lock); -+ pool_thread_offline (&deferreds.pool); -+ return NULL; -+} -+ -+/* Allocate storage for a deferred function. A pointer to a buffer of -+ the given size is returned. */ -+void * -+_pager_allocate_deferred (deferred_function_t f, size_t size) -+{ -+ struct deferred *d = malloc (sizeof *d + size); -+ if (d != NULL) -+ d->function = f; -+ return &d->args; -+} -+ -+/* Enqueue the given deferred function. Expects a pointer returned -+ from _pager_allocate_deferred. */ -+void -+_pager_defer (void *cookie) -+{ -+ int idle; -+ struct deferred *d = (struct deferred *) -+ ((char *) cookie - offsetof (struct deferred, args)); -+ -+ pthread_mutex_lock (&deferreds.lock); -+ -+ queue_enqueue (&deferreds.queue, &d->item); -+ -+ idle = pool_idle_threads (&deferreds.pool); -+ if (idle > 0) -+ /* Awake worker. */ -+ pthread_cond_signal (&deferreds.wakeup); -+ else -+ { -+ /* Limit the creation of threads using the token bucket -+ algorithm. */ -+ struct timeval elapsed, last = deferreds.last_check; -+ maptime_read (mapped_time, &deferreds.last_check); -+ timersub (&deferreds.last_check, &last, &elapsed); -+ -+ deferreds.bucket += -+ ((float) elapsed.tv_sec + (float) elapsed.tv_sec / 1000000.) -+ * (DEFERREDS_BUCKET_SIZE / DEFERREDS_BUCKET_PER); -+ -+ if (deferreds.bucket > DEFERREDS_BUCKET_SIZE) -+ deferreds.bucket = DEFERREDS_BUCKET_SIZE; -+ -+ if (deferreds.bucket > 1.) -+ { -+ error_t err; -+ pthread_t t; -+ TRACE ("creating deferred worker thread"); -+ err = pthread_create (&t, &pool_thread_attr, -+ &deferreds_worker_func, NULL); -+ if (err) -+ /* This is tough. Let's hope for the best. */ -+ error (0, err, "pthread_create"); -+ else -+ { -+ pthread_detach (t); -+ deferreds.bucket -= 1.; -+ } -+ } -+ } -+ -+ pthread_mutex_unlock (&deferreds.lock); -+} -+ -+/* Initializes the queue and starts the deferred workers. */ -+error_t -+_pager_deferreds_init (void) -+{ -+ error_t err = 0; -+ int i; -+ pthread_t t; -+ -+ /* Try the unprivileged method using /dev/time first. */ -+ err = maptime_map (0, NULL, &mapped_time); -+ if (err) -+ { -+ /* Fall back to using the time mach device. */ -+ err = maptime_map (1, NULL, &mapped_time); -+ if (err) -+ return err; -+ } -+ -+ queue_init (&deferreds.queue); -+ pthread_cond_init (&deferreds.wakeup, NULL); -+ pthread_mutex_init (&deferreds.lock, NULL); -+ -+ for (i = 0; i < DEFERREDS_MIN_IDLE; i++) -+ { -+ err = pthread_create (&t, &pool_thread_attr, -+ &deferreds_worker_func, NULL); -+ if (err) -+ return err; -+ -+ pthread_detach (t); -+ } -+ deferreds.bucket = DEFERREDS_BUCKET_SIZE; -+ maptime_read (mapped_time, &deferreds.last_check); -+ -+ return err; -+} -diff --git a/libpager/deferreds.h b/libpager/deferreds.h -new file mode 100644 -index 0000000..5cc9aed ---- /dev/null -+++ b/libpager/deferreds.h -@@ -0,0 +1,42 @@ -+/* Deferred function queue. -+ -+ Copyright (C) 2014 Free Software Foundation, Inc. -+ -+ Written by Justus Winter <4winter@informatik.uni-hamburg.de> -+ -+ This file is part of the GNU Hurd. -+ -+ The GNU Hurd is free software; you can redistribute it and/or -+ modify it under the terms of the GNU General Public License as -+ published by the Free Software Foundation; either version 2, or (at -+ your option) any later version. -+ -+ The GNU Hurd is distributed in the hope that it will be useful, but -+ WITHOUT ANY WARRANTY; without even the implied warranty of -+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU -+ General Public License for more details. -+ -+ You should have received a copy of the GNU General Public License -+ along with the GNU Hurd. If not, see <http://www.gnu.org/licenses/>. */ -+ -+#ifndef _LIBPAGER_DEFERREDS_H -+#define _LIBPAGER_DEFERREDS_H -+ -+#include <errno.h> -+#include <stddef.h> -+ -+/* Type for deferred functions. */ -+typedef void (*deferred_function_t) (void *); -+ -+/* Initializes the queue and starts the deferred workers. */ -+error_t _pager_deferreds_init (void); -+ -+/* Allocate storage for a deferred function. A pointer to a buffer of -+ the given size is returned. */ -+void *_pager_allocate_deferred (deferred_function_t, size_t); -+ -+/* Enqueue the given deferred function. Expects a pointer returned -+ from _pager_allocate_deferred. */ -+void _pager_defer (void *); -+ -+#endif /* _LIBPAGER_DEFERREDS_H */ -diff --git a/libpager/demuxer.c b/libpager/demuxer.c -index b4d4054..e3eb06c 100644 ---- a/libpager/demuxer.c -+++ b/libpager/demuxer.c -@@ -1,5 +1,5 @@ - /* Demuxer for pager library -- Copyright (C) 1994, 1995, 2002, 2011 Free Software Foundation -+ Copyright (C) 1994, 1995, 2002, 2011, 2014 Free Software Foundation - - This program is free software; you can redistribute it and/or - modify it under the terms of the GNU General Public License as -@@ -15,26 +15,286 @@ - along with this program; if not, write to the Free Software - Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ - -+#include <error.h> -+#include <mach/mig_errors.h> -+#include <pthread.h> -+#include <string.h> -+ - #include "priv.h" - #include "memory_object_S.h" - #include "notify_S.h" -+#include "deferreds.h" -+#include "pool.h" -+#include "queue.h" -+ -+/* -+ Worker pool for the server functions. -+ -+ A single thread receives messages from the port bucket and puts them -+ into a queue. A fixed number of consumers actually execute the -+ server functions and send the reply. -+ -+ The requests to an object O have to be processed in the order they -+ were received. To this end, each worker has a local queue and a -+ tag. If a thread processes a request to O, it sets its tag to a -+ unique identifier representing O. If another thread now dequeues a -+ second request to O, it enqueues it to the first workers queue. -+ -+ This is an optimization based on the observation that multiple -+ requests to the same objects often come in quick succession. This -+ also makes sure that the second request is processed at the earliest -+ possible moment, by the same thread that processed the previous -+ request to that object. -+ -+ At least one worker thread is necessary. -+*/ -+#define WORKER_COUNT 3 -+ -+/* An request contains the message received from the port set. */ -+struct request -+{ -+ struct item item; -+ mig_routine_t routine; -+ mach_msg_header_t *inp; -+ mach_msg_header_t *outp; -+}; -+ -+/* A worker. */ -+struct worker -+{ -+ struct queue queue; /* other workers may delegate requests to us */ -+ unsigned long tag; /* tag of the object we are working on */ -+}; -+ -+/* This is the queue for incoming requests. A single thread receives -+ messages from the port set, looks the service routine up, and -+ enqueues the request here. */ -+static struct -+{ -+ struct queue queue; -+ int asleep; -+ pthread_cond_t wakeup; -+ pthread_mutex_t lock; -+ struct worker workers[WORKER_COUNT]; -+} requests; - - /* Demultiplex a single message directed at a pager port; INP is the - message received; fill OUTP with the reply. */ --int -+static int - pager_demuxer (mach_msg_header_t *inp, - mach_msg_header_t *outp) - { -+ error_t err = MIG_NO_REPLY; -+ -+#ifdef MACH_RCV_LARGE -+ const mach_msg_size_t max_size = 2 * __vm_page_size; /* Generic. Good? XXX */ -+#else -+ const mach_msg_size_t max_size = 4 * __vm_page_size; /* XXX */ -+#endif -+ - mig_routine_t routine; -- if ((routine = _pager_seqnos_memory_object_server_routine (inp)) || -- (routine = _pager_seqnos_notify_server_routine (inp))) -+ if (! ((routine = _pager_seqnos_memory_object_server_routine (inp)) || -+ (routine = _pager_seqnos_notify_server_routine (inp)))) -+ return FALSE; -+ -+#define MASK (8 - 1) -+ mach_msg_size_t padded_size = (inp->msgh_size + MASK) & ~MASK; -+#undef MASK -+ -+ struct request *r = malloc (sizeof *r + padded_size + max_size); -+ if (r == NULL) - { -- (*routine) (inp, outp); -- return TRUE; -+ err = ENOMEM; -+ goto out; -+ } -+ -+ r->routine = routine; -+ r->inp = (mach_msg_header_t *) ((char *) r + sizeof *r); -+ memcpy (r->inp, inp, inp->msgh_size); -+ -+ r->outp = (mach_msg_header_t *) ((char *) r + sizeof *r + padded_size); -+ memcpy (r->outp, outp, sizeof *outp); -+ -+ pthread_mutex_lock (&requests.lock); -+ -+ queue_enqueue (&requests.queue, &r->item); -+ -+ /* Awake worker. */ -+ if (requests.asleep > 0) -+ pthread_cond_signal (&requests.wakeup); -+ -+ pthread_mutex_unlock (&requests.lock); -+ -+ out: -+ ((mig_reply_header_t *) outp)->RetCode = err; -+ return TRUE; -+} -+ -+/* Consumes requests from the queue. */ -+static void * -+worker_func (void *arg) -+{ -+ struct worker *self = (struct worker *) arg; -+ struct request *r = NULL; -+ -+ while (1) -+ { -+ int i; -+ mach_msg_return_t mr; -+ -+ /* Free previous message. */ -+ free (r); -+ -+ pthread_mutex_lock (&requests.lock); -+ -+ /* First, look in our queue for more requests to the object we -+ have been working on lately. Some other thread might have -+ delegated them to us. */ -+ r = queue_dequeue (&self->queue); -+ if (r != NULL) -+ goto got_one; -+ -+ /* Nope. Clear our tag and... */ -+ self->tag = 0; -+ -+ get_request_locked: -+ /* ... get a request from the global queue instead. */ -+ while ((r = queue_dequeue (&requests.queue)) == NULL) -+ { -+ requests.asleep += 1; -+ pthread_cond_wait (&requests.wakeup, &requests.lock); -+ requests.asleep -= 1; -+ } -+ -+ for (i = 0; i < WORKER_COUNT; i++) -+ if (requests.workers[i].tag -+ == (unsigned long) r->inp->msgh_local_port) -+ { -+ /* Some other thread is working on that object. Delegate -+ the request to that worker. */ -+ queue_enqueue (&requests.workers[i].queue, &r->item); -+ goto get_request_locked; -+ } -+ -+ /* Claim responsibility for this object by setting our tag. */ -+ self->tag = (unsigned long) r->inp->msgh_local_port; -+ -+ got_one: -+ pthread_mutex_unlock (&requests.lock); -+ -+ /* Call the server routine. */ -+ (*r->routine) (r->inp, r->outp); -+ -+ /* What follows is basically the second part of -+ mach_msg_server_timeout. */ -+ mig_reply_header_t *request = (mig_reply_header_t *) r->inp; -+ mig_reply_header_t *reply = (mig_reply_header_t *) r->outp; -+ -+ switch (reply->RetCode) -+ { -+ case KERN_SUCCESS: -+ /* Hunky dory. */ -+ break; -+ -+ case MIG_NO_REPLY: -+ /* The server function wanted no reply sent. -+ Loop for another request. */ -+ continue; -+ -+ default: -+ /* Some error; destroy the request message to release any -+ port rights or VM it holds. Don't destroy the reply port -+ right, so we can send an error message. */ -+ request->Head.msgh_remote_port = MACH_PORT_NULL; -+ mach_msg_destroy (&request->Head); -+ break; -+ } -+ -+ if (reply->Head.msgh_remote_port == MACH_PORT_NULL) -+ { -+ /* No reply port, so destroy the reply. */ -+ if (reply->Head.msgh_bits & MACH_MSGH_BITS_COMPLEX) -+ mach_msg_destroy (&reply->Head); -+ continue; -+ } -+ -+ /* Send the reply. */ -+ mr = mach_msg (&reply->Head, -+ MACH_SEND_MSG, -+ reply->Head.msgh_size, -+ 0, -+ MACH_PORT_NULL, -+ 0, -+ MACH_PORT_NULL); -+ -+ switch (mr) -+ { -+ case MACH_SEND_INVALID_DEST: -+ /* The reply can't be delivered, so destroy it. This error -+ indicates only that the requester went away, so we -+ continue and get the next request. */ -+ mach_msg_destroy (&reply->Head); -+ break; -+ -+ default: -+ /* Some other form of lossage; there is not much we can -+ do here. */ -+ error (0, mr, "mach_msg"); -+ } -+ } -+ -+ /* Not reached. */ -+ return NULL; -+} -+ -+/* A top-level function for the paging thread that just services paging -+ requests. */ -+static void * -+service_paging_requests (void *arg) -+{ -+ struct port_bucket *pager_bucket = arg; -+ ports_manage_port_operations_one_thread (pager_bucket, -+ pager_demuxer, -+ 0); -+ /* Not reached. */ -+ return NULL; -+} -+ -+/* Start the worker thread libpager uses to service requests. */ -+error_t -+pager_start_workers (struct port_bucket *pager_bucket) -+{ -+ error_t err; -+ int i; -+ pthread_t t; -+ -+ pool_init (); -+ err = _pager_deferreds_init (); -+ if (err) -+ return err; -+ -+ queue_init (&requests.queue); -+ pthread_cond_init (&requests.wakeup, NULL); -+ pthread_mutex_init (&requests.lock, NULL); -+ -+ /* Make a thread to service paging requests. */ -+ err = pthread_create (&t, &pool_thread_attr, -+ service_paging_requests, pager_bucket); -+ if (err) -+ return err; -+ pthread_detach (t); -+ -+ for (i = 0; i < WORKER_COUNT; i++) -+ { -+ requests.workers[i].tag = 0; -+ queue_init (&requests.workers[i].queue); -+ -+ err = pthread_create (&t, &pool_thread_attr, -+ &worker_func, &requests.workers[i]); -+ if (err) -+ return err; -+ pthread_detach (t); - } - -- /* Synchronize our bookkeeping of the port's seqno with the one -- consumed by this bogus message. */ -- _pager_update_seqno (inp->msgh_local_port, inp->msgh_seqno); -- return FALSE; -+ return err; - } -diff --git a/libpager/lock-completed.c b/libpager/lock-completed.c -index a3f3f16..30b1dd3 100644 ---- a/libpager/lock-completed.c -+++ b/libpager/lock-completed.c -@@ -37,7 +37,6 @@ _pager_seqnos_memory_object_lock_completed (struct pager *p, - return EOPNOTSUPP; - - pthread_mutex_lock (&p->interlock); -- _pager_wait_for_seqno (p, seqno); - - if (control != p->memobjcntl) - { -@@ -59,7 +58,6 @@ _pager_seqnos_memory_object_lock_completed (struct pager *p, - } - - out: -- _pager_release_seqno (p, seqno); - pthread_mutex_unlock (&p->interlock); - - return err; -diff --git a/libpager/no-senders.c b/libpager/no-senders.c -index c21dfc2..d0bbe27 100644 ---- a/libpager/no-senders.c -+++ b/libpager/no-senders.c -@@ -29,7 +29,6 @@ _pager_do_seqnos_mach_notify_no_senders (struct port_info *pi, - pi->class != _pager_class) - return EOPNOTSUPP; - -- _pager_update_seqno_p ((struct pager *) pi, seqno); - ports_no_senders (pi, mscount); - - return 0; -diff --git a/libpager/notify-stubs.c b/libpager/notify-stubs.c -index ba13882..a826420 100644 ---- a/libpager/notify-stubs.c -+++ b/libpager/notify-stubs.c -@@ -28,8 +28,6 @@ _pager_do_seqnos_mach_notify_port_deleted (struct port_info *pi, - mach_port_t name - __attribute__ ((unused))) - { -- _pager_update_seqno_p ((struct pager *) pi, seqno); -- - return 0; - } - -@@ -39,8 +37,6 @@ _pager_do_seqnos_mach_notify_msg_accepted (struct port_info *pi, - mach_port_t name - __attribute__ ((unused))) - { -- _pager_update_seqno_p ((struct pager *) pi, seqno); -- - return 0; - } - -@@ -50,8 +46,6 @@ _pager_do_seqnos_mach_notify_port_destroyed (struct port_info *pi, - mach_port_t name - __attribute__ ((unused))) - { -- _pager_update_seqno_p ((struct pager *) pi, seqno); -- - return 0; - } - -@@ -59,8 +53,6 @@ error_t - _pager_do_seqnos_mach_notify_send_once (struct port_info *pi, - mach_port_seqno_t seqno) - { -- _pager_update_seqno_p ((struct pager *) pi, seqno); -- - return 0; - } - -@@ -70,7 +62,5 @@ _pager_do_seqnos_mach_notify_dead_name (struct port_info *pi, - mach_port_t name - __attribute__ ((unused))) - { -- _pager_update_seqno_p ((struct pager *) pi, seqno); -- - return 0; - } -diff --git a/libpager/object-init.c b/libpager/object-init.c -index 6683e24..eb62c44 100644 ---- a/libpager/object-init.c -+++ b/libpager/object-init.c -@@ -33,7 +33,6 @@ _pager_seqnos_memory_object_init (struct pager *p, - return EOPNOTSUPP; - - pthread_mutex_lock (&p->interlock); -- _pager_wait_for_seqno (p, seqno); - - if (pagesize != __vm_page_size) - { -@@ -69,7 +68,6 @@ _pager_seqnos_memory_object_init (struct pager *p, - p->pager_state = NORMAL; - - out: -- _pager_release_seqno (p, seqno); - pthread_mutex_unlock (&p->interlock); - - return 0; -diff --git a/libpager/object-terminate.c b/libpager/object-terminate.c -index 365ba27..3f0482f 100644 ---- a/libpager/object-terminate.c -+++ b/libpager/object-terminate.c -@@ -32,8 +32,7 @@ _pager_seqnos_memory_object_terminate (struct pager *p, - return EOPNOTSUPP; - - pthread_mutex_lock (&p->interlock); -- _pager_wait_for_seqno (p, seqno); -- -+ - if (control != p->memobjcntl) - { - printf ("incg terminate: wrong control port"); -@@ -75,7 +74,6 @@ _pager_seqnos_memory_object_terminate (struct pager *p, - #endif - - out: -- _pager_release_seqno (p, seqno); - pthread_mutex_unlock (&p->interlock); - - return 0; -diff --git a/libpager/pager.h b/libpager/pager.h -index d0572af..d209290 100644 ---- a/libpager/pager.h -+++ b/libpager/pager.h -@@ -25,11 +25,8 @@ - scope. */ - struct user_pager_info; - --/* This de-muxer function is for use within libports_demuxer. */ --/* INP is a message we've received; OUTP will be filled in with -- a reply message. */ --int pager_demuxer (mach_msg_header_t *inp, -- mach_msg_header_t *outp); -+/* Start the worker thread libpager uses to service requests. */ -+error_t pager_start_workers (struct port_bucket *pager_bucket); - - /* Create a new pager. The pager will have a port created for it - (using libports, in BUCKET) and will be immediately ready -diff --git a/libpager/pool.c b/libpager/pool.c -new file mode 100644 -index 0000000..c64b46e ---- /dev/null -+++ b/libpager/pool.c -@@ -0,0 +1,103 @@ -+/* A thread pool. -+ -+ Copyright (C) 2014 Free Software Foundation, Inc. -+ -+ Written by Justus Winter <4winter@informatik.uni-hamburg.de> -+ -+ This file is part of the GNU Hurd. -+ -+ The GNU Hurd is free software; you can redistribute it and/or -+ modify it under the terms of the GNU General Public License as -+ published by the Free Software Foundation; either version 2, or (at -+ your option) any later version. -+ -+ The GNU Hurd is distributed in the hope that it will be useful, but -+ WITHOUT ANY WARRANTY; without even the implied warranty of -+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU -+ General Public License for more details. -+ -+ You should have received a copy of the GNU General Public License -+ along with the GNU Hurd. If not, see <http://www.gnu.org/licenses/>. */ -+ -+#include <error.h> -+#include <pthread.h> -+ -+/* XXX Copied from libports. */ -+#include <mach.h> -+#include <hurd.h> -+#include <mach/thread_info.h> -+#include <mach/thread_switch.h> -+ -+#define STACK_SIZE (64 * 1024) -+ -+#define THREAD_PRI 2 -+ -+/* XXX To reduce starvation, the priority of new threads is initially -+ depressed. This helps already existing threads complete their job and be -+ recycled to handle new messages. The duration of this depression is made -+ a function of the total number of threads because more threads imply -+ more contention, and the priority of threads blocking on a contended spin -+ lock is also implicitely depressed. -+ -+ Then, if permitted, a greater priority is requested to further decrease -+ the need for additional threads. */ -+void -+adjust_priority (unsigned int totalthreads) -+{ -+ mach_port_t host_priv, self, pset, pset_priv; -+ unsigned int t; -+ error_t err; -+ -+ t = 10 + (((totalthreads - 1) / 100) + 1) * 10; -+ thread_switch (MACH_PORT_NULL, SWITCH_OPTION_DEPRESS, t); -+ -+ err = get_privileged_ports (&host_priv, NULL); -+ if (err) -+ goto error_host_priv; -+ -+ self = mach_thread_self (); -+ err = thread_get_assignment (self, &pset); -+ if (err) -+ goto error_pset; -+ -+ err = host_processor_set_priv (host_priv, pset, &pset_priv); -+ if (err) -+ goto error_pset_priv; -+ -+ err = thread_max_priority (self, pset_priv, 0); -+ if (err) -+ goto error_max_priority; -+ -+ err = thread_priority (self, THREAD_PRI, 0); -+ if (err) -+ goto error_priority; -+ -+ mach_port_deallocate (mach_task_self (), pset_priv); -+ mach_port_deallocate (mach_task_self (), pset); -+ mach_port_deallocate (mach_task_self (), self); -+ mach_port_deallocate (mach_task_self (), host_priv); -+ return; -+ -+error_priority: -+error_max_priority: -+ mach_port_deallocate (mach_task_self (), pset_priv); -+error_pset_priv: -+ mach_port_deallocate (mach_task_self (), pset); -+error_pset: -+ mach_port_deallocate (mach_task_self (), self); -+ mach_port_deallocate (mach_task_self (), host_priv); -+error_host_priv: -+ if (err != EPERM) -+ error (0, err, "unable to adjust libports thread priority"); -+} -+ -+/* Attributes for newly created threads. */ -+pthread_attr_t pool_thread_attr; -+ -+/* Initializes pool_thread_attr. */ -+void -+pool_init (void) -+{ -+ pthread_attr_init (&pool_thread_attr); -+ pthread_attr_setstacksize (&pool_thread_attr, STACK_SIZE); -+} -diff --git a/libpager/pool.h b/libpager/pool.h -new file mode 100644 -index 0000000..6fa538d ---- /dev/null -+++ b/libpager/pool.h -@@ -0,0 +1,79 @@ -+/* A thread pool. -+ -+ Copyright (C) 2014 Free Software Foundation, Inc. -+ -+ Written by Justus Winter <4winter@informatik.uni-hamburg.de> -+ -+ This file is part of the GNU Hurd. -+ -+ The GNU Hurd is free software; you can redistribute it and/or -+ modify it under the terms of the GNU General Public License as -+ published by the Free Software Foundation; either version 2, or (at -+ your option) any later version. -+ -+ The GNU Hurd is distributed in the hope that it will be useful, but -+ WITHOUT ANY WARRANTY; without even the implied warranty of -+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU -+ General Public License for more details. -+ -+ You should have received a copy of the GNU General Public License -+ along with the GNU Hurd. If not, see <http://www.gnu.org/licenses/>. */ -+ -+#ifndef _LIBPAGER_POOL_H -+#define _LIBPAGER_POOL_H -+ -+/* A thread pool. */ -+struct pool -+{ -+ int alive; -+ int idle; -+}; -+ -+static inline int -+pool_thread_online (struct pool *p) -+{ -+ return __atomic_add_fetch (&p->alive, 1, __ATOMIC_RELAXED); -+} -+ -+static inline int -+pool_thread_offline (struct pool *p) -+{ -+ return __atomic_sub_fetch (&p->alive, 1, __ATOMIC_RELAXED); -+} -+ -+static inline int -+pool_idle_threads (struct pool *p) -+{ -+ return __atomic_load_n (&p->idle, __ATOMIC_RELAXED); -+} -+ -+static inline int -+pool_thread_idle (struct pool *p) -+{ -+ return __atomic_add_fetch (&p->idle, 1, __ATOMIC_RELAXED); -+} -+ -+static inline int -+pool_thread_busy (struct pool *p) -+{ -+ return __atomic_sub_fetch (&p->idle, 1, __ATOMIC_RELAXED); -+} -+ -+/* XXX To reduce starvation, the priority of new threads is initially -+ depressed. This helps already existing threads complete their job and be -+ recycled to handle new messages. The duration of this depression is made -+ a function of the total number of threads because more threads imply -+ more contention, and the priority of threads blocking on a contended spin -+ lock is also implicitely depressed. -+ -+ Then, if permitted, a greater priority is requested to further decrease -+ the need for additional threads. */ -+void adjust_priority (unsigned int totalthreads); -+ -+/* Attributes for newly created threads. */ -+extern pthread_attr_t pool_thread_attr; -+ -+/* Initializes pool_thread_attr. */ -+void pool_init (void); -+ -+#endif /* _LIBPAGER_POOL_H */ -diff --git a/libpager/priv.h b/libpager/priv.h -index d49cbb9..b1d56b5 100644 ---- a/libpager/priv.h -+++ b/libpager/priv.h -@@ -136,10 +136,6 @@ extern int _pager_page_errors[]; - struct port_class *_pager_class; - - --void _pager_wait_for_seqno (struct pager *, mach_port_seqno_t); --void _pager_release_seqno (struct pager *, mach_port_seqno_t); --void _pager_update_seqno (mach_port_t, mach_port_seqno_t); --void _pager_update_seqno_p (struct pager *, mach_port_seqno_t); - void _pager_block_termination (struct pager *); - void _pager_allow_termination (struct pager *); - error_t _pager_pagemap_resize (struct pager *, vm_address_t); -diff --git a/libpager/queue.h b/libpager/queue.h -new file mode 100644 -index 0000000..d3cf738 ---- /dev/null -+++ b/libpager/queue.h -@@ -0,0 +1,61 @@ -+/* A FIFO queue with constant-time enqueue and dequeue operations. -+ -+ Copyright (C) 2014 Free Software Foundation, Inc. -+ -+ Written by Justus Winter <4winter@informatik.uni-hamburg.de> -+ -+ This file is part of the GNU Hurd. -+ -+ The GNU Hurd is free software; you can redistribute it and/or -+ modify it under the terms of the GNU General Public License as -+ published by the Free Software Foundation; either version 2, or (at -+ your option) any later version. -+ -+ The GNU Hurd is distributed in the hope that it will be useful, but -+ WITHOUT ANY WARRANTY; without even the implied warranty of -+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU -+ General Public License for more details. -+ -+ You should have received a copy of the GNU General Public License -+ along with the GNU Hurd. If not, see <http://www.gnu.org/licenses/>. */ -+ -+/* A FIFO queue with constant-time enqueue and dequeue operations. */ -+struct item { -+ struct item *next; -+}; -+ -+struct queue { -+ struct item *head; -+ struct item **tail; -+}; -+ -+static inline void -+queue_init (struct queue *q) -+{ -+ q->head = NULL; -+ q->tail = &q->head; -+} -+ -+static inline void -+queue_enqueue (struct queue *q, struct item *r) -+{ -+ *q->tail = r; -+ q->tail = &r->next; -+ r->next = NULL; -+} -+ -+static inline void * -+queue_dequeue (struct queue *q) -+{ -+ struct item *r = q->head; -+ if (r == NULL) -+ return NULL; -+ -+ /* Pop the first item off. */ -+ if ((q->head = q->head->next) == NULL) -+ /* The queue is empty, fix tail pointer. */ -+ q->tail = &q->head; -+ -+ r->next = NULL; -+ return r; -+} -diff --git a/libpager/seqnos.c b/libpager/seqnos.c -deleted file mode 100644 -index cab2f33..0000000 ---- a/libpager/seqnos.c -+++ /dev/null -@@ -1,79 +0,0 @@ --/* Sequence number synchronization routines for pager library -- Copyright (C) 1994, 2011 Free Software Foundation -- -- This program is free software; you can redistribute it and/or -- modify it under the terms of the GNU General Public License as -- published by the Free Software Foundation; either version 2, or (at -- your option) any later version. -- -- This program is distributed in the hope that it will be useful, but -- WITHOUT ANY WARRANTY; without even the implied warranty of -- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU -- General Public License for more details. -- -- You should have received a copy of the GNU General Public License -- along with this program; if not, write to the Free Software -- Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ -- --#include "priv.h" --#include <assert.h> -- --/* The message with seqno SEQNO has just been dequeued for pager P; -- wait until all preceding messages have had a chance and then -- return. */ --void --_pager_wait_for_seqno (struct pager *p, -- mach_port_seqno_t seqno) --{ -- while (seqno != p->seqno + 1) -- { -- p->waitingforseqno = 1; -- pthread_cond_wait (&p->wakeup, &p->interlock); -- } --} -- -- --/* Allow the next message for pager P (potentially blocked in -- _pager_wait_for_seqno) to be handled. */ --void --_pager_release_seqno (struct pager *p, -- mach_port_seqno_t seqno) --{ -- assert (seqno == p->seqno + 1); -- p->seqno = seqno; -- if (p->waitingforseqno) -- { -- p->waitingforseqno = 0; -- pthread_cond_broadcast (&p->wakeup); -- } --} -- -- --/* Just update the seqno. */ --void --_pager_update_seqno (mach_port_t object, -- mach_port_seqno_t seqno) --{ -- struct pager *p; -- -- p = ports_lookup_port (0, object, _pager_class); -- _pager_update_seqno_p (p, seqno); -- if (p) -- ports_port_deref (p); --} -- -- --/* Just update the seqno, pointer version. */ --void --_pager_update_seqno_p (struct pager *p, -- mach_port_seqno_t seqno) --{ -- if (p -- && p->port.class == _pager_class) -- { -- pthread_mutex_lock (&p->interlock); -- _pager_wait_for_seqno (p, seqno); -- _pager_release_seqno (p, seqno); -- pthread_mutex_unlock (&p->interlock); -- } --} -diff --git a/libpager/stubs.c b/libpager/stubs.c -index 411f483..c7f1a5a 100644 ---- a/libpager/stubs.c -+++ b/libpager/stubs.c -@@ -29,9 +29,6 @@ _pager_seqnos_memory_object_copy (struct pager *p, - mach_port_t new) - { - printf ("m_o_copy called\n"); -- -- _pager_update_seqno_p (p, seq); -- - return EOPNOTSUPP; - } - -@@ -44,9 +41,6 @@ _pager_seqnos_memory_object_data_write (struct pager *p, - vm_size_t data_cnt) - { - printf ("m_o_data_write called\n"); -- -- _pager_update_seqno_p (p, seq); -- - return EOPNOTSUPP; - } - -@@ -60,8 +54,5 @@ _pager_seqnos_memory_object_supply_completed (struct pager *p, - vm_offset_t err_off) - { - printf ("m_o_supply_completed called\n"); -- -- _pager_update_seqno_p (p, seq); -- - return EOPNOTSUPP; - } -diff --git a/storeio/pager.c b/storeio/pager.c -index 7d78711..e123ad1 100644 ---- a/storeio/pager.c -+++ b/storeio/pager.c -@@ -24,6 +24,7 @@ - #include <strings.h> - #include <unistd.h> - #include <errno.h> -+#include <error.h> - #include <sys/mman.h> - #include <stdio.h> - -@@ -142,21 +143,6 @@ pager_clear_user_data (struct user_pager_info *upi) - - static struct port_bucket *pager_port_bucket = 0; - --/* A top-level function for the paging thread that just services paging -- requests. */ --static void * --service_paging_requests (void *arg) --{ -- (void) arg; -- -- for (;;) -- ports_manage_port_operations_multithread (pager_port_bucket, -- pager_demuxer, -- 1000 * 30, 1000 * 60 * 5, 0); -- -- return NULL; --} -- - /* Initialize paging for this device. */ - static void - init_dev_paging () -@@ -173,14 +159,12 @@ init_dev_paging () - - pager_port_bucket = ports_create_bucket (); - -- /* Make a thread to service paging requests. */ -- err = pthread_create (&thread, NULL, service_paging_requests, NULL); -- if (!err) -- pthread_detach (thread); -- else -+ /* Start libpagers worker thread. */ -+ err = pager_start_workers (pager_port_bucket); -+ if (err) - { - errno = err; -- perror ("pthread_create"); -+ error (0, err, "pager_start_workers"); - } - } - pthread_mutex_unlock (&pager_global_lock); diff --git a/debian/patches/series b/debian/patches/series index 03af894c..a95de89e 100644 --- a/debian/patches/series +++ b/debian/patches/series @@ -49,6 +49,5 @@ ext2fs-two-pagers.patch #ext2fs-simplify-expression.patch needs refresh ^ ext2fs-fix-inum-type.patch #ext2fs-cache-superblock.patch -#libpager-threading-rework.patch exec-abbreviate-task-names.patch libpager-singlethreaded.patch |