Changeset 223950 in webkit

Timestamp:

Oct 24, 2017 11:55:36 PM (6 years ago)

Author:

zandobersek@gmail.com

Message:

[Linux] Enable Gigacage in x64 Linux environment
​https://bugs.webkit.org/show_bug.cgi?id=177745
<rdar://problem/34773148>

Reviewed by Yusuke Suzuki.

Re-enable Gigacage on x86_64 Linux platforms after it was disabled in 223877.

The cause for the revert was problems with huge coredumps being generated
while Gigacage was enabled. The feature virtually allocates about 80GB of
memory at the beginning of the process lifetime. This is not a problem in
itself since the memory range is marked as not needed through madvise(),
but all this memory was still included upon core dump generation on Linux.
Since there are reasonable limits enforced upon core dumps, these were
being truncated every time, not yielding any useful information.

To avoid this, on Linux, invocations of madvise() with the MADV_NORMAL and
MADV_DONTNEED advice parameters should be accompanied with respectively
matching MADV_DODUMP and MADV_DONTDUMP madvise() calls. This correctly
avoids core-dumping any memory that's not yet been physically allocated.

• bmalloc/Gigacage.h:
• bmalloc/VMAllocate.h:

(bmalloc::vmDeallocatePhysicalPages):
(bmalloc::vmAllocatePhysicalPages):

Location:

trunk/Source/bmalloc

Files:

• ChangeLog (modified) (1 diff)
• bmalloc/Gigacage.h (modified) (1 diff)
• bmalloc/VMAllocate.h (modified) (2 diffs)

trunk/Source/bmalloc/ChangeLog

@@ +1 @@
+2017-10-24  Zan Dobersek  <zdobersek@igalia.com>
+
+        [Linux] Enable Gigacage in x64 Linux environment
+        https://bugs.webkit.org/show_bug.cgi?id=177745
+        <rdar://problem/34773148>
+
+        Reviewed by Yusuke Suzuki.
+
+        Re-enable Gigacage on x86_64 Linux platforms after it was disabled in 223877.
+
+        The cause for the revert was problems with huge coredumps being generated
+        while Gigacage was enabled. The feature virtually allocates about 80GB of
+        memory at the beginning of the process lifetime. This is not a problem in
+        itself since the memory range is marked as not needed through madvise(),
+        but all this memory was still included upon core dump generation on Linux.
+        Since there are reasonable limits enforced upon core dumps, these were
+        being truncated every time, not yielding any useful information.
+
+        To avoid this, on Linux, invocations of madvise() with the MADV_NORMAL and
+        MADV_DONTNEED advice parameters should be accompanied with respectively
+        matching MADV_DODUMP and MADV_DONTDUMP madvise() calls. This correctly
+        avoids core-dumping any memory that's not yet been physically allocated.
+
+        * bmalloc/Gigacage.h:
+        * bmalloc/VMAllocate.h:
+        (bmalloc::vmDeallocatePhysicalPages):
+        (bmalloc::vmAllocatePhysicalPages):
+
 2017-10-24  David Kilzer  <ddkilzer@apple.com>
 

trunk/Source/bmalloc/bmalloc/Gigacage.h

@@ -53 +53 @@
 #define STRING_GIGACAGE_MASK GIGACAGE_SIZE_TO_MASK(STRING_GIGACAGE_SIZE)
 
-#if (BOS(DARWIN) && (BCPU(ARM64) || BCPU(X86_64)))
+#if (BOS(DARWIN) && (BCPU(ARM64) || BCPU(X86_64))) || (BOS(LINUX) && BCPU(X86_64))
 #define GIGACAGE_ENABLED 1
 #else

trunk/Source/bmalloc/bmalloc/VMAllocate.h

@@ -194 +194 @@
 #else
     SYSCALL(madvise(p, vmSize, MADV_DONTNEED));
+#if BOS(LINUX)
+    SYSCALL(madvise(p, vmSize, MADV_DONTDUMP));
+#endif
 #endif
 }
@@ -204 +207 @@
 #else
     SYSCALL(madvise(p, vmSize, MADV_NORMAL));
+#if BOS(LINUX)
+    SYSCALL(madvise(p, vmSize, MADV_DODUMP));
+#endif
 #endif
 }