Using madvise for ld.so

[Michael Matz]

Hi,

On Tue, 16 Mar 2004, Michael Matz wrote:

> did so (thanks to Lubos for fixing a silly error in it).

Hmpf.  I sent the patch with that error.  Trying again ;-)


Ciao,
Michael.
-- 
diff -upr sysdeps.orig/generic/ldsodefs.h sysdeps/generic/ldsodefs.h
--- sysdeps.orig/generic/ldsodefs.h	2004-03-09 17:51:44.000000000 +0100
+++ sysdeps/generic/ldsodefs.h	2004-03-09 16:31:45.000000000 +0100
@@ -282,6 +282,8 @@ struct rtld_global
   /* Do we do lazy relocations?  */
   EXTERN int _dl_lazy;
 
+  EXTERN int _dl_madvise;
+
   /* Nonzero if runtime lookups should not update the .got/.plt.  */
   EXTERN int _dl_bind_not;
 
diff -upr sysdeps.orig/unix/sysv/linux/syscalls.list sysdeps/unix/sysv/linux/syscalls.list
--- sysdeps.orig/unix/sysv/linux/syscalls.list	2003-09-08 08:42:40.000000000 +0200
+++ sysdeps/unix/sysv/linux/syscalls.list	2004-03-09 17:19:46.000000000 +0100
@@ -29,7 +29,7 @@ iopl		-	iopl		i:i	iopl
 klogctl		EXTRA	syslog		i:isi	klogctl
 lchown		-	lchown		i:sii	__lchown	lchown
 posix_madvise	-	madvise		Vi:pii	posix_madvise
-madvise		-	madvise		i:pii	madvise
+madvise		-	madvise		i:pii	__madvise	madvise
 mincore		-	mincore		i:anV	mincore
 mlock		-	mlock		i:bn	mlock
 mlockall	-	mlockall	i:i	mlockall
diff -upr elf.orig/dl-load.c elf/dl-load.c
--- elf.orig/dl-load.c	2004-02-22 20:33:36.000000000 +0100
+++ elf/dl-load.c	2004-03-09 17:19:07.000000000 +0100
@@ -1101,6 +1101,9 @@ cannot allocate TLS data structures for 
 	    goto call_lose_errno;
 	  }
 
+	if (GLRO(dl_madvise))
+	  __madvise ((void *) l->l_map_start, maplength, MADV_WILLNEED);
+
 	l->l_map_end = l->l_map_start + maplength;
 	l->l_addr = l->l_map_start - c->mapstart;
 
diff -upr elf.orig/dl-support.c elf/dl-support.c
--- elf.orig/dl-support.c	2004-01-28 07:53:55.000000000 +0100
+++ elf/dl-support.c	2004-03-09 17:47:53.000000000 +0100
@@ -41,6 +41,7 @@ size_t _dl_platformlen;
 
 int _dl_debug_mask;
 int _dl_lazy;
+int _dl_madvise;
 ElfW(Addr) _dl_use_load_bias = -2;
 int _dl_dynamic_weak;
 
@@ -243,6 +244,8 @@ _dl_non_dynamic_init (void)
 
   _dl_lazy = *(getenv ("LD_BIND_NOW") ?: "") == '\0';
 
+  _dl_madvise = *(getenv ("LD_NOMADVISE") ?: "") == '\0';
+
   _dl_bind_not = *(getenv ("LD_BIND_NOT") ?: "") != '\0';
 
   _dl_dynamic_weak = *(getenv ("LD_DYNAMIC_WEAK") ?: "") == '\0';
diff -upr elf.orig/rtld.c elf/rtld.c
--- elf.orig/rtld.c	2004-03-09 11:35:17.000000000 +0100
+++ elf/rtld.c	2004-03-09 17:47:24.000000000 +0100
@@ -122,6 +122,7 @@
     ._dl_hwcap_mask = HWCAP_IMPORTANT,
     ._dl_lazy = 1,
     ._dl_fpu_control = _FPU_DEFAULT,
+    ._dl_madvise = 1,

     /* Function pointers.  */
     ._dl_get_origin = _dl_get_origin,
@@ -2086,6 +2087,12 @@ process_envvars (enum mode *modep)
 	  break;
 
 	case 9:
+	  if (memcmp (envline, "NOMADVISE", 9) == 0)
+	    {
+	      GLRO(dl_madvise) = envline[10] == '\0';
+	      break;
+	    }
+
 	  /* Test whether we want to see the content of the auxiliary
 	     array passed up from the kernel.  */
 	  if (memcmp (envline, "SHOW_AUXV", 9) == 0)
diff -upr include.orig/sys/mman.h include/sys/mman.h
--- include.orig/sys/mman.h	1999-11-26 09:16:29.000000000 +0100
+++ include/sys/mman.h	2004-03-09 17:18:50.000000000 +0100
@@ -8,6 +8,7 @@ extern void *__mmap64 (void *__addr, siz
 		       int __flags, int __fd, __off64_t __offset);
 extern int __munmap (void *__addr, size_t __len);
 extern int __mprotect (void *__addr, size_t __len, int __prot);
+extern int __madvise (void *__addr, size_t __len, int __advise);
 
 /* This one is Linux specific.  */
 extern void *__mremap (void *__addr, size_t __old_len,