On Tue, 27 Nov 2001, William A. Rowe, Jr. wrote:
> Better yet.
>
> If APR_MMAP_LIMIT is exceeded, break it into n APR_MMAP_LIMIT sized buckets,
> wherein only one bucket may be mapped at a time.
> What I'm suggesting is that as each bucket is consumed, it is un-memaped.
> The buckets are only mmaped as they are read. This way, we get the benefits
> of mmap, without the pain of page consumption.
Absolutely.
That's actually what I had in mind. I forgot about the friggin pool
cleanup doing the apr_mmap_delete() for us rather than mmap_destroy()
doing it. Feh.
Maybe the newly-introduced mmap "ownership" concept can help us here. If
the mmap bucket holds the apr_mmap_t that "owns" the OS mmap, then the
buckets code's mmap_destroy() can safely munmap the thing. We should now
actually always be able to call apr_mmap_delete() from mmap_destroy()
safely, because apr_mmap_delete() knows about the owner concept and just
returns success if it's not the owner. That would be nice, actually,
because we wouldn't have to worry about cases like mmap_destroy()
munmaping an mmap owned by mod_file_cache, for example.
So I guess it would look something like this:
Index: apr_buckets_file.c
===================================================================
RCS file: /home/cvs/apr-util/buckets/apr_buckets_file.c,v
retrieving revision 1.61
diff -u -d -r1.61 apr_buckets_file.c
--- apr_buckets_file.c 2001/11/28 00:38:00 1.61
+++ apr_buckets_file.c 2001/11/28 04:26:13
@@ -84,15 +84,25 @@
apr_bucket_file *a = e->data;
apr_mmap_t *mm;
- if (APR_MMAP_CANDIDATE(filelength) &&
- (apr_mmap_create(&mm, a->fd, fileoffset, filelength,
- APR_MMAP_READ, p) == APR_SUCCESS))
+ if (filelength > APR_MMAP_LIMIT) {
+ if (apr_mmap_create(&mm, a->fd, fileoffset, APR_MMAP_LIMIT,
+ APR_MMAP_READ, p) != APR_SUCCESS) {
+ return 0;
+ }
+ else {
+ apr_bucket_split(e, APR_MMAP_LIMIT);
+ filelength = APR_MMAP_LIMIT;
+ }
+ }
+ else if ((filelength >= APR_MMAP_THRESHOLD) &&
+ (apr_mmap_create(&mm, a->fd, fileoffset, filelength,
+ APR_MMAP_READ, p) != APR_SUCCESS))
{
- apr_bucket_mmap_make(e, mm, 0, filelength);
- file_destroy(a);
- return 1;
+ return 0;
}
- return 0;
+ apr_bucket_mmap_make(e, mm, 0, filelength);
+ file_destroy(a);
+ return 1;
}
#endif
Index: apr_buckets_mmap.c
===================================================================
RCS file: /home/cvs/apr-util/buckets/apr_buckets_mmap.c,v
retrieving revision 1.44
diff -u -d -r1.44 apr_buckets_mmap.c
--- apr_buckets_mmap.c 2001/11/21 17:00:51 1.44
+++ apr_buckets_mmap.c 2001/11/28 04:26:13
@@ -80,8 +80,7 @@
apr_bucket_mmap *m = data;
if (apr_bucket_shared_destroy(m)) {
- /* no need to apr_mmap_delete(m->mmap) here... it will
- * get done automatically when the pool gets cleaned up. */
+ apr_mmap_delete(m->mmap);
free(m);
}
}
[Tested to compile but not to work ;]
Thoughts?
--Cliff
--------------------------------------------------------------
Cliff Woolley
[EMAIL PROTECTED]
Charlottesville, VA
