diff options
Diffstat (limited to 'debian/patches/vm-cache-policy0001-VM-cache-policy-change.patch')
| -rw-r--r-- | debian/patches/vm-cache-policy0001-VM-cache-policy-change.patch | 346 |
1 files changed, 0 insertions, 346 deletions
diff --git a/debian/patches/vm-cache-policy0001-VM-cache-policy-change.patch b/debian/patches/vm-cache-policy0001-VM-cache-policy-change.patch deleted file mode 100644 index 2fef1e2..0000000 --- a/debian/patches/vm-cache-policy0001-VM-cache-policy-change.patch +++ /dev/null @@ -1,346 +0,0 @@ -From dcbdadadcd006e6b9b8ced1dffa4d47a91557d08 Mon Sep 17 00:00:00 2001 -From: Richard Braun <rbraun@sceen.net> -Date: Wed, 9 Oct 2013 11:51:54 +0200 -Subject: [PATCH gnumach 1/3] VM cache policy change - -This patch lets the kernel unconditionnally cache non empty unreferenced -objects instead of using a fixed arbitrary limit. As the pageout daemon -evicts pages, it collects cached objects that have become empty. The -effective result is a graceful adjustment of the number of objects -related to memory management (virtual memory objects, their associated -ports, and potentially objects maintained in the external memory -managers). Physical memory can now be almost entirely filled up with -cached pages. In addition, these cached pages are not automatically -deactivated as objects can quickly be referenced again. - -There are problems with this patch however. The first is that, on -machines with a large amount of physical memory (above 1 GiB but it also -depends on usage patterns), scalability issues are exposed. For example, -file systems which don't throttle their writeback requests can create -thread storms, strongly reducing system responsiveness. Other issues -such as linear scans of memory objects also add visible CPU overhead. - -The second is that, as most memory is used, it increases the chances of -swapping deadlocks. Applications that map large objects and quickly -cause lots of page faults can still easily bring the system to its -knees. ---- - vm/vm_object.c | 166 ++++++++++++++++++------------------------------------- - vm/vm_object.h | 7 ++- - vm/vm_pageout.c | 7 ++- - vm/vm_resident.c | 4 +- - 4 files changed, 68 insertions(+), 116 deletions(-) - -diff --git a/vm/vm_object.c b/vm/vm_object.c -index a026348..44c13f4 100644 ---- a/vm/vm_object.c -+++ b/vm/vm_object.c -@@ -59,6 +59,11 @@ - #include <ddb/db_output.h> - #endif /* MACH_KDB */ - -+void memory_object_release( -+ ipc_port_t pager, -+ pager_request_t pager_request, -+ ipc_port_t pager_name); /* forward */ -+ - /* - * Virtual memory objects maintain the actual data - * associated with allocated virtual memory. A given -@@ -159,8 +164,9 @@ vm_object_t kernel_object = &kernel_object_store; - * - * The kernel may choose to terminate objects from this - * queue in order to reclaim storage. The current policy -- * is to permit a fixed maximum number of unreferenced -- * objects (vm_object_cached_max). -+ * is to let memory pressure dynamically adjust the number -+ * of unreferenced objects. The pageout daemon attempts to -+ * collect objects after removing pages from them. - * - * A simple lock (accessed by routines - * vm_object_cache_{lock,lock_try,unlock}) governs the -@@ -176,7 +182,6 @@ vm_object_t kernel_object = &kernel_object_store; - */ - queue_head_t vm_object_cached_list; - int vm_object_cached_count; --int vm_object_cached_max = 4000; /* may be patched*/ - - decl_simple_lock_data(,vm_object_cached_lock_data) - -@@ -343,6 +348,33 @@ void vm_object_init(void) - IKOT_PAGING_NAME); - } - -+void vm_object_collect( -+ register vm_object_t object) -+{ -+ vm_object_unlock(object); -+ -+ /* -+ * The cache lock must be acquired in the proper order. -+ */ -+ -+ vm_object_cache_lock(); -+ vm_object_lock(object); -+ -+ /* -+ * If the object was referenced while the lock was -+ * dropped, cancel the termination. -+ */ -+ -+ if (!vm_object_collectable(object)) { -+ vm_object_unlock(object); -+ vm_object_cache_unlock(); -+ return; -+ } -+ -+ queue_remove(&vm_object_cached_list, object, vm_object_t, cached_list); -+ vm_object_terminate(object); -+} -+ - /* - * vm_object_reference: - * -@@ -403,103 +435,35 @@ void vm_object_deallocate( - - /* - * See whether this object can persist. If so, enter -- * it in the cache, then deactivate all of its -- * pages. -+ * it in the cache. - */ -- if (object->can_persist) { -- boolean_t overflow; -- -- /* -- * Enter the object onto the queue -- * of "cached" objects. Remember whether -- * we've caused the queue to overflow, -- * as a hint. -- */ -- -+ if (object->can_persist && (object->resident_page_count > 0)) { - queue_enter(&vm_object_cached_list, object, - vm_object_t, cached_list); -- overflow = (++vm_object_cached_count > vm_object_cached_max); -+ vm_object_cached_count++; - vm_object_cached_pages_update(object->resident_page_count); - vm_object_cache_unlock(); - -- vm_object_deactivate_pages(object); - vm_object_unlock(object); -+ return; -+ } - -- /* -- * If we didn't overflow, or if the queue has -- * been reduced back to below the specified -- * minimum, then quit. -- */ -- if (!overflow) -- return; -- -- while (TRUE) { -- vm_object_cache_lock(); -- if (vm_object_cached_count <= -- vm_object_cached_max) { -- vm_object_cache_unlock(); -- return; -- } -- -- /* -- * If we must trim down the queue, take -- * the first object, and proceed to -- * terminate it instead of the original -- * object. Have to wait for pager init. -- * if it's in progress. -- */ -- object= (vm_object_t) -- queue_first(&vm_object_cached_list); -- vm_object_lock(object); -- -- if (!(object->pager_created && -- !object->pager_initialized)) { -- -- /* -- * Ok to terminate, hang on to lock. -- */ -- break; -- } -- -- vm_object_assert_wait(object, -- VM_OBJECT_EVENT_INITIALIZED, FALSE); -- vm_object_unlock(object); -- vm_object_cache_unlock(); -- thread_block((void (*)()) 0); -- -- /* -- * Continue loop to check if cache still -- * needs to be trimmed. -- */ -- } -+ if (object->pager_created && -+ !object->pager_initialized) { - - /* -- * Actually remove object from cache. -+ * Have to wait for initialization. -+ * Put reference back and retry -+ * when it's initialized. - */ - -- queue_remove(&vm_object_cached_list, object, -- vm_object_t, cached_list); -- vm_object_cached_count--; -- -- assert(object->ref_count == 0); -- } -- else { -- if (object->pager_created && -- !object->pager_initialized) { -- -- /* -- * Have to wait for initialization. -- * Put reference back and retry -- * when it's initialized. -- */ -- object->ref_count++; -- vm_object_assert_wait(object, -- VM_OBJECT_EVENT_INITIALIZED, FALSE); -- vm_object_unlock(object); -- vm_object_cache_unlock(); -- thread_block((void (*)()) 0); -- continue; -- } -+ object->ref_count++; -+ vm_object_assert_wait(object, -+ VM_OBJECT_EVENT_INITIALIZED, FALSE); -+ vm_object_unlock(object); -+ vm_object_cache_unlock(); -+ thread_block((void (*)()) 0); -+ continue; - } - - /* -@@ -862,28 +826,6 @@ kern_return_t memory_object_destroy( - } - - /* -- * vm_object_deactivate_pages -- * -- * Deactivate all pages in the specified object. (Keep its pages -- * in memory even though it is no longer referenced.) -- * -- * The object must be locked. -- */ --void vm_object_deactivate_pages( -- vm_object_t object) --{ -- vm_page_t p; -- -- queue_iterate(&object->memq, p, vm_page_t, listq) { -- vm_page_lock_queues(); -- if (!p->busy) -- vm_page_deactivate(p); -- vm_page_unlock_queues(); -- } --} -- -- --/* - * Routine: vm_object_pmap_protect - * - * Purpose: -@@ -2701,7 +2643,7 @@ void vm_object_page_remove( - * It balances vm_object_lookup vs iteration. - */ - -- if (atop(end - start) < (unsigned)object->resident_page_count/16) { -+ if (atop(end - start) < object->resident_page_count/16) { - vm_object_page_remove_lookup++; - - for (; start < end; start += PAGE_SIZE) { -@@ -2926,7 +2868,7 @@ void vm_object_print( - iprintf("Object 0x%X: size=0x%X, %d references\n", - (vm_offset_t) object, (vm_offset_t) object->size, - object->ref_count); -- iprintf("%d resident pages,", object->resident_page_count); -+ iprintf("%lu resident pages,", object->resident_page_count); - printf(" %d absent pages,", object->absent_count); - printf(" %d paging ops\n", object->paging_in_progress); - indent += 1; -diff --git a/vm/vm_object.h b/vm/vm_object.h -index 3bfc67a..fa208aa 100644 ---- a/vm/vm_object.h -+++ b/vm/vm_object.h -@@ -72,7 +72,7 @@ struct vm_object { - */ - - int ref_count; /* Number of references */ -- int resident_page_count; -+ unsigned long resident_page_count; - /* number of resident pages */ - - struct vm_object *copy; /* Object that should receive -@@ -169,6 +169,7 @@ vm_object_t kernel_object; /* the single kernel object */ - - extern void vm_object_bootstrap(void); - extern void vm_object_init(void); -+extern void vm_object_collect(vm_object_t); - extern void vm_object_terminate(vm_object_t); - extern vm_object_t vm_object_allocate(vm_size_t); - extern void vm_object_reference(vm_object_t); -@@ -290,6 +291,10 @@ vm_object_t vm_object_copy_delayed( - * Routines implemented as macros - */ - -+#define vm_object_collectable(object) \ -+ (((object)->ref_count == 0) \ -+ && ((object)->resident_page_count == 0)) -+ - #define vm_object_paging_begin(object) \ - ((object)->paging_in_progress++) - -diff --git a/vm/vm_pageout.c b/vm/vm_pageout.c -index 51a6a0d..5e1ad1d 100644 ---- a/vm/vm_pageout.c -+++ b/vm/vm_pageout.c -@@ -748,7 +748,12 @@ void vm_pageout_scan(void) - reclaim_page: - vm_page_free(m); - vm_page_unlock_queues(); -- vm_object_unlock(object); -+ -+ if (vm_object_collectable(object)) -+ vm_object_collect(object); -+ else -+ vm_object_unlock(object); -+ - continue; - } - -diff --git a/vm/vm_resident.c b/vm/vm_resident.c -index c70fa73..b65b756 100644 ---- a/vm/vm_resident.c -+++ b/vm/vm_resident.c -@@ -523,7 +523,7 @@ void vm_page_insert( - */ - - object->resident_page_count++; -- assert(object->resident_page_count >= 0); -+ assert(object->resident_page_count != 0); - - if (object->can_persist && (object->ref_count == 0)) - vm_object_cached_pages_update(1); -@@ -630,7 +630,7 @@ void vm_page_replace( - */ - - object->resident_page_count++; -- assert(object->resident_page_count >= 0); -+ assert(object->resident_page_count != 0); - - if (object->can_persist && (object->ref_count == 0)) - vm_object_cached_pages_update(1); --- -2.1.4 - |