From: Martin Mares <mj@ucw.cz>
Date: Mon, 16 Jan 2006 19:41:56 +0000 (+0000)
Subject: On 64-bit architectures, partmap is just an mmap.
X-Git-Tag: holmes-import~693
X-Git-Url: http://mj.ucw.cz/gitweb/?a=commitdiff_plain;h=95d18fdbc7274c501eed2ecce3861452aaa4a50c;p=libucw.git

On 64-bit architectures, partmap is just an mmap.
On all architectures, it calls madvise() to optimize for sequential access.
---

diff --git a/lib/autoconf.cfg b/lib/autoconf.cfg
index 4485db74..3c81f034 100644
--- a/lib/autoconf.cfg
+++ b/lib/autoconf.cfg
@@ -170,6 +170,9 @@ if (IsSet("CONFIG_DEBUG")) {
 	Append("LOPT" => "-s");
 }
 
+# Decide how will lib/partmap.c work
+Set("PARTMAP_IS_MMAP") if IsSet("CPU_64BIT_POINTERS");
+
 # If debugging memory allocations:
 #LIBS+=-lefence
 #CDEBUG+=-DDEBUG_DMALLOC
diff --git a/lib/partmap.c b/lib/partmap.c
index 60ec168c..49f12322 100644
--- a/lib/partmap.c
+++ b/lib/partmap.c
@@ -1,7 +1,7 @@
 /*
  *	UCW Library -- Mapping of File Parts
  *
- *	(c) 2003 Martin Mares <mj@ucw.cz>
+ *	(c) 2003--2006 Martin Mares <mj@ucw.cz>
  *	(c) 2003--2005 Robert Spalek <robert@ucw.cz>
  *
  *	This software may be freely distributed and used according to the terms
@@ -20,11 +20,15 @@
 #include <sys/mman.h>
 #include <sys/user.h>
 
+#ifdef CONFIG_PARTMAP_IS_MMAP
+#define PARTMAP_WINDOW ~(size_t)0
+#else
 #ifdef TEST
 #define PARTMAP_WINDOW 4096
 #else
 #define PARTMAP_WINDOW 16777216
 #endif
+#endif
 
 struct partmap *
 partmap_open(byte *name, int writeable)
@@ -37,6 +41,9 @@ partmap_open(byte *name, int writeable)
   if ((p->file_size = sh_seek(p->fd, 0, SEEK_END)) < 0)
     die("lseek(%s): %m", name);
   p->writeable = writeable;
+#ifdef CONFIG_PARTMAP_IS_MMAP
+  partmap_load(p, 0, p->file_size);
+#endif
   return p;
 }
 
@@ -62,7 +69,7 @@ partmap_load(struct partmap *p, sh_off_t start, uns size)
     munmap(p->start_map, p->end_off - p->start_off);
   sh_off_t end = start + size;
   sh_off_t win_start = start/PAGE_SIZE * PAGE_SIZE;
-  uns win_len = PARTMAP_WINDOW;
+  size_t win_len = PARTMAP_WINDOW;
   if ((sh_off_t) (win_start+win_len) > p->file_size)
     win_len = ALIGN(p->file_size - win_start, PAGE_SIZE);
   if ((sh_off_t) (win_start+win_len) < end)
@@ -72,6 +79,7 @@ partmap_load(struct partmap *p, sh_off_t start, uns size)
     die("mmap failed at position %Ld: %m", (long long)win_start);
   p->start_off = win_start;
   p->end_off = win_start+win_len;
+  madvise(p->start_map, win_len, MADV_SEQUENTIAL);
 }
 
 #ifdef TEST
diff --git a/lib/partmap.h b/lib/partmap.h
index b5c48099..1be70ded 100644
--- a/lib/partmap.h
+++ b/lib/partmap.h
@@ -1,7 +1,7 @@
 /*
  *	UCW Library -- Mapping of File Parts
  *
- *	(c) 2003 Martin Mares <mj@ucw.cz>
+ *	(c) 2003--2006 Martin Mares <mj@ucw.cz>
  *	(c) 2003--2005 Robert Spalek <robert@ucw.cz>
  *
  *	This software may be freely distributed and used according to the terms
@@ -25,18 +25,22 @@ sh_off_t partmap_size(struct partmap *p);
 void partmap_load(struct partmap *p, sh_off_t start, uns size);
 
 static inline void *
-partmap_map(struct partmap *p, sh_off_t start, uns size)
+partmap_map(struct partmap *p, sh_off_t start, uns size UNUSED)
 {
+#ifndef CONFIG_PARTMAP_IS_MMAP
   if (unlikely(!p->start_map || start < p->start_off || (sh_off_t) (start+size) > p->end_off))
     partmap_load(p, start, size);
+#endif
   return p->start_map + (start - p->start_off);
 }
 
 static inline void *
-partmap_map_forward(struct partmap *p, sh_off_t start, uns size)
+partmap_map_forward(struct partmap *p, sh_off_t start, uns size UNUSED)
 {
+#ifndef CONFIG_PARTMAP_IS_MMAP
   if (unlikely((sh_off_t) (start+size) > p->end_off))
     partmap_load(p, start, size);
+#endif
   return p->start_map + (start - p->start_off);
 }