Attachment 346465 Details for Bug 188299 – patch

[patch] patch

process-limit-notifications.patch (text/plain), 5.33 KB, created by Antti Koivisto on 2018-08-03 02:29:57 PDT

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Creator: Antti Koivisto

Created: 2018-08-03 02:29:57 PDT

Size: 5.33 KB

patch

obsolete

>Index: Source/WTF/ChangeLog
>===================================================================
>--- Source/WTF/ChangeLog	(revision 234539)
>+++ Source/WTF/ChangeLog	(working copy)
>@@ -1,3 +1,25 @@
>+2018-08-03  Antti Koivisto  <antti@apple.com>
>+
>+        Web process never leaves memory pressured state if caused by per-process limit
>+        https://bugs.webkit.org/show_bug.cgi?id=188299
>+        <rdar://problem/42157442>
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        For system memory pressure warnings we get signaled when exiting the state so we can clear
>+        the isUnderMemoryPressure bit. However as a compatibility behavior we were also notified using
>+        the same notifications when approaching the per-process limit. In this case there is no "all clear"
>+        notification so we'd stay in pressured state forever, leading to unnecessarily degraded user experience.
>+
>+        * wtf/cocoa/MemoryPressureHandlerCocoa.mm:
>+        (WTF::MemoryPressureHandler::install):
>+
>+        Install a handler for per-process notifications. This disables the compatibility behavior,
>+        vm pressure notifications will be received for vm pressure only.
>+
>+        Per-process notifications are treated as one-shot things. We do cleanups based on criticality but
>+        don't enter the pressured state.
>+
> 2018-08-02  Saam Barati  <sbarati@apple.com>
> 
>         Reading instructionPointer from PlatformRegisters may fail when using pointer tagging
>Index: Source/WTF/wtf/cocoa/MemoryPressureHandlerCocoa.mm
>===================================================================
>--- Source/WTF/wtf/cocoa/MemoryPressureHandlerCocoa.mm	(revision 234496)
>+++ Source/WTF/wtf/cocoa/MemoryPressureHandlerCocoa.mm	(working copy)
>@@ -31,6 +31,10 @@
> #import <malloc/malloc.h>
> #import <notify.h>
> 
>+#if USE(APPLE_INTERNAL_SDK)
>+#include <dispatch/private.h>
>+#endif
>+
> #define ENABLE_FMW_FOOTPRINT_COMPARISON 0
> 
> extern "C" void cache_simulate_memory_warning_event(uint64_t);
>@@ -68,30 +72,52 @@ void MemoryPressureHandler::install()
> 
>     dispatch_async(dispatch_get_main_queue(), ^{
> #if PLATFORM(IOS)
>-        _cache_event_source = dispatch_source_create(DISPATCH_SOURCE_TYPE_MEMORYPRESSURE, 0, DISPATCH_MEMORYPRESSURE_NORMAL | DISPATCH_MEMORYPRESSURE_WARN | DISPATCH_MEMORYPRESSURE_CRITICAL, dispatch_get_main_queue());
>-#elif PLATFORM(MAC)
>-        _cache_event_source = dispatch_source_create(DISPATCH_SOURCE_TYPE_MEMORYPRESSURE, 0, DISPATCH_MEMORYPRESSURE_CRITICAL, dispatch_get_main_queue());
>+        auto memoryStatusFlags = DISPATCH_MEMORYPRESSURE_NORMAL | DISPATCH_MEMORYPRESSURE_WARN | DISPATCH_MEMORYPRESSURE_CRITICAL;
>+#if USE(APPLE_INTERNAL_SDK)
>+        memoryStatusFlags |= DISPATCH_MEMORYPRESSURE_PROC_LIMIT_WARN | DISPATCH_MEMORYPRESSURE_PROC_LIMIT_CRITICAL;
>+#endif
>+#else // PLATFORM(MAC)
>+        auto memoryStatusFlags = DISPATCH_MEMORYPRESSURE_CRITICAL;
>+        auto isCritical = true;
> #endif
>+        _cache_event_source = dispatch_source_create(DISPATCH_SOURCE_TYPE_MEMORYPRESSURE, 0, memoryStatusFlags, dispatch_get_main_queue());
> 
>         dispatch_set_context(_cache_event_source, this);
>         dispatch_source_set_event_handler(_cache_event_source, ^{
>-            bool critical = true;
> #if PLATFORM(IOS)
>             unsigned long status = dispatch_source_get_data(_cache_event_source);
>-            critical = status == DISPATCH_MEMORYPRESSURE_CRITICAL;
>-            auto& memoryPressureHandler = MemoryPressureHandler::singleton();
>-            bool wasCritical = memoryPressureHandler.isUnderMemoryPressure();
>-            memoryPressureHandler.setUnderMemoryPressure(critical);
>+            
>+            // Per process notification are one shot things while the system status is a state.
>+            bool isUnderVMMemoryPressure = [&] {
>+                if (status == DISPATCH_MEMORYPRESSURE_CRITICAL)
>+                    return true;
>+                if (status == DISPATCH_MEMORYPRESSURE_NORMAL)
>+                    return false;
>+                return MemoryPressureHandler::singleton().isUnderMemoryPressure();
>+            }();
>+
>+            bool isCritical = [&] {
>+                if (status == DISPATCH_MEMORYPRESSURE_CRITICAL)
>+                    return true;
>+#if USE(APPLE_INTERNAL_SDK)
>+                if (status == DISPATCH_MEMORYPRESSURE_PROC_LIMIT_CRITICAL)
>+                    return true;
>+#endif
>+                return false;
>+            }();
>+
>+            MemoryPressureHandler::singleton().setUnderMemoryPressure(isUnderVMMemoryPressure);
>+
>             if (status == DISPATCH_MEMORYPRESSURE_NORMAL) {
>                 if (ReliefLogger::loggingEnabled())
>-                    NSLog(@"System is no longer under (%s) memory pressure.", wasCritical ? "critical" : "non-critical");
>+                    NSLog(@"System is no longer under memory pressure.");
>                 return;
>             }
> 
>             if (ReliefLogger::loggingEnabled())
>-                NSLog(@"Got memory pressure notification (%s)", critical ? "critical" : "non-critical");
>+                NSLog(@"Got memory pressure notification %lu (%s)", status, isCritical ? "critical" : "non-critical");
> #endif
>-            MemoryPressureHandler::singleton().respondToMemoryPressure(critical ? Critical::Yes : Critical::No);
>+            MemoryPressureHandler::singleton().respondToMemoryPressure(isCritical ? Critical::Yes : Critical::No);
>         });
>         dispatch_resume(_cache_event_source);
>     });

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Attachments on bug 188299: 346465 | 346470 | 346599 | 346625