From: Martin Mares <mj@ucw.cz>
Date: Fri, 27 Sep 2002 21:46:28 +0000 (+0000)
Subject: The fb-mmap module, now read/write. Still needs a lot of benchmarking before we decide
X-Git-Tag: holmes-import~1334
X-Git-Url: http://mj.ucw.cz/gitweb/?a=commitdiff_plain;h=9b2d0bbed694a76120ff1315060cdc587c38f18a;p=libucw.git

The fb-mmap module, now read/write. Still needs a lot of benchmarking before we decide
to switch the indexer to use it.
---

diff --git a/lib/Makefile b/lib/Makefile
index 4fbc7a19..759c2d0d 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -8,7 +8,7 @@ SHLIB_OBJS=alloc.o alloc_str.o ctmatch.o db.o fastbuf.o fb-file.o fb-mem.o lists
 	prime.o random.o realloc.o regex.o timer.o url.o wildmatch.o \
 	wordsplit.o str_ctype.o str_upper.o bucket.o conf.o object.o sorter.o \
 	finger.o proctitle.o ipaccess.o profile.o bitsig.o randomkey.o \
-	hashfunc.o base64.o base224.o fb-temp.o printf.o
+	hashfunc.o base64.o base224.o fb-temp.o printf.o fb-mmap.o
 
 obj/lib/libsh.a: $(addprefix obj/lib/,$(SHLIB_OBJS)) $(CUSTOM_MODULES)
 
diff --git a/lib/fb-mmap.c b/lib/fb-mmap.c
new file mode 100644
index 00000000..c9d7b10c
--- /dev/null
+++ b/lib/fb-mmap.c
@@ -0,0 +1,213 @@
+/*
+ *	Sherlock Library -- Fast Buffered I/O on Memory-Mapped Files
+ *
+ *	(c) 2002 Martin Mares <mj@ucw.cz>
+ *
+ *	This software may be freely distributed and used according to the terms
+ *	of the GNU Lesser General Public License.
+ */
+
+/*
+ *  FIXME:
+ *  - problems with temp files
+ *  - O_WRONLY ? (& generally processing of mode bits)
+ */
+
+#ifdef TEST
+#define MMAP_WINDOW_SIZE 16*PAGE_SIZE
+#define MMAP_EXTEND_SIZE 4*PAGE_SIZE
+#else
+#define MMAP_WINDOW_SIZE 256*PAGE_SIZE
+#define MMAP_EXTEND_SIZE 256*PAGE_SIZE
+#endif
+
+#include "lib/lib.h"
+#include "lib/fastbuf.h"
+#include "lib/lfs.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <sys/user.h>
+
+struct fb_mmap {
+  struct fastbuf fb;
+  int fd;
+  int dummy;				/* FIXME: dirty hack for is_temp_file, remove */
+  sh_off_t file_size;
+  sh_off_t file_extend;
+  sh_off_t window_pos;
+  int is_writeable;
+};
+#define FB_MMAP(f) ((struct fb_mmap *)(f)->is_fastbuf)
+
+static void
+bfmm_map_window(struct fastbuf *f)
+{
+  struct fb_mmap *F = FB_MMAP(f);
+  sh_off_t pos0 = f->pos & ~(sh_off_t)(PAGE_SIZE-1);
+  int l = MIN(MMAP_WINDOW_SIZE, F->file_extend - pos0);
+  uns ll = ALIGN(l, PAGE_SIZE);
+  uns oll = ALIGN(f->bufend - f->buffer, PAGE_SIZE);
+  int prot = F->is_writeable ? (PROT_READ | PROT_WRITE) : PROT_READ;
+
+  DBG(" ... Mapping %x(%x)+%x(%x) len=%x extend=%x", (int)pos0, (int)f->pos, ll, l, (int)F->file_size, (int)F->file_extend);
+  if (ll != oll)
+    {
+      munmap(f->buffer, oll);
+      f->buffer = NULL;
+    }
+  if (!f->buffer)
+    f->buffer = sh_mmap(NULL, ll, prot, MAP_SHARED, F->fd, pos0);
+  else
+    f->buffer = sh_mmap(f->buffer, ll, prot, MAP_SHARED | MAP_FIXED, F->fd, pos0);
+  if (f->buffer == (byte *) MAP_FAILED)
+    die("mmap(%s): %m", f->name);
+  if (ll > PAGE_SIZE)
+    madvise(f->buffer, ll, MADV_SEQUENTIAL);
+  f->bufend = f->buffer + l;
+  f->bptr = f->buffer + (f->pos - pos0);
+  F->window_pos = f->pos;
+}
+
+static int
+bfmm_refill(struct fastbuf *f)
+{
+  struct fb_mmap *F = FB_MMAP(f);
+
+  DBG("Refill <- %p %p %p %p", f->buffer, f->bptr, f->bstop, f->bufend);
+  if (f->pos >= F->file_size)
+    return 0;
+  if (f->bstop >= f->bufend)
+    bfmm_map_window(f);
+  if (F->window_pos + (f->bufend - f->buffer) > F->file_size)
+    f->bstop = f->buffer + (F->file_size - F->window_pos);
+  else
+    f->bstop = f->bufend;
+  f->pos = F->window_pos + (f->bstop - f->buffer);
+  DBG(" -> %p %p %p(%x) %p", f->buffer, f->bptr, f->bstop, (int)f->pos, f->bufend);
+  return 1;
+}
+
+static void
+bfmm_spout(struct fastbuf *f)
+{
+  struct fb_mmap *F = FB_MMAP(f);
+  sh_off_t end = f->pos + (f->bptr - f->bstop);
+
+  DBG("Spout <- %p %p %p %p", f->buffer, f->bptr, f->bstop, f->bufend);
+  if (end > F->file_size)
+    F->file_size = end;
+  if (f->bptr < f->bufend)
+    return;
+  f->pos = end;
+  if (f->pos >= F->file_extend)
+    {
+      F->file_extend = ALIGN(F->file_extend + MMAP_EXTEND_SIZE, (sh_off_t)PAGE_SIZE);
+      if (sh_ftruncate(F->fd, F->file_extend))
+	die("ftruncate(%s): %m", f->name);
+    }
+  bfmm_map_window(f);
+  f->bstop = f->bptr;
+  DBG(" -> %p %p %p(%x) %p", f->buffer, f->bptr, f->bstop, (int)f->pos, f->bufend);
+}
+
+static void
+bfmm_seek(struct fastbuf *f, sh_off_t pos, int whence)
+{
+  if (whence == SEEK_END)
+    pos += FB_MMAP(f)->file_size;
+  else
+    ASSERT(whence == SEEK_SET);
+  ASSERT(pos >= 0 && pos <= FB_MMAP(f)->file_size);
+  f->pos = pos;
+  f->bptr = f->bstop = f->bufend;	/* force refill/spout call */
+  DBG("Seek -> %p %p %p(%x) %p", f->buffer, f->bptr, f->bstop, (int)f->pos, f->bufend);
+}
+
+static void
+bfmm_close(struct fastbuf *f)
+{
+  struct fb_mmap *F = FB_MMAP(f);
+
+  if (f->buffer)
+    munmap(f->buffer, ALIGN(f->bufend-f->buffer, PAGE_SIZE));
+  if (F->file_extend > F->file_size &&
+      sh_ftruncate(F->fd, F->file_size))
+    die("ftruncate(%s): %m", f->name);
+  close(F->fd);
+  xfree(f);
+}
+
+static struct fastbuf *
+bfmmopen_internal(int fd, byte *name, uns mode)
+{
+  int namelen = strlen(name) + 1;
+  struct fb_mmap *F = xmalloc(sizeof(struct fb_mmap) + namelen);
+  struct fastbuf *f = &F->fb;
+
+  bzero(F, sizeof(*F));
+  f->name = (byte *)(F+1);
+  memcpy(f->name, name, namelen);
+  F->fd = fd;
+  F->file_extend = F->file_size = sh_seek(fd, 0, SEEK_END);
+  if (mode & O_APPEND)
+    f->pos = F->file_size;
+  mode &= ~O_APPEND;
+  if (mode & O_WRONLY || mode & O_RDWR)
+    F->is_writeable = 1;
+
+  f->refill = bfmm_refill;
+  f->spout = bfmm_spout;
+  f->seek = bfmm_seek;
+  f->close = bfmm_close;
+  return f;
+}
+
+struct fastbuf *
+bopen_mm(byte *name, uns mode)
+{
+  int fd = sh_open(name, mode, 0666);
+  if (fd < 0)
+    die("Unable to %s file %s: %m",
+	(mode & O_CREAT) ? "create" : "open", name);
+  return bfmmopen_internal(fd, name, mode);
+}
+
+#ifdef TEST
+
+int main(int argc, char **argv)
+{
+  struct fastbuf *f = bopen_mm(argv[1], O_RDONLY);
+  struct fastbuf *g = bopen_mm(argv[2], O_RDWR | O_CREAT | O_TRUNC);
+  int c;
+
+  DBG("Copying");
+  while ((c = bgetc(f)) >= 0)
+    bputc(g, c);
+  bclose(f);
+  DBG("Seek inside last block");
+  bsetpos(g, btell(g)-1333);
+  bputc(g, 13);
+  DBG("Seek to the beginning & write");
+  bsetpos(g, 1333);
+  bputc(g, 13);
+  DBG("flush");
+  bflush(g);
+  bputc(g, 13);
+  bflush(g);
+  DBG("Seek nearby & read");
+  bsetpos(g, 133);
+  bgetc(g);
+  DBG("Seek far & read");
+  bsetpos(g, 133333);
+  bgetc(g);
+  DBG("Closing");
+  bclose(g);
+
+  return 0;
+}
+
+#endif