was wrong, so fix it right this time. undo the previous change and
instead, replace the troublesome VOP_FSYNC()s with code that just flushes
the particular indirect blocks that we allocated. this resolves the
softdeps for those blocks. then we can change the pointer for
the first indirect block we allocated to zero, write that, and finally
invalidate all the indirect blocks we've touched. also, wait until
after we finish all this before freeing any blocks we allocated.
fixes PRs 14413 and 14423.
deal with the fragment expansion separately before the rest of the operation.
this allows us to simplify ufs_balloc_range() by not worrying about implicit
fragment expansion.
call VOP_PUTPAGES() directly for vnodes instead of
going through the UVM pager "put" vector.
- calculate the offset and length of the postbl before byteswapping.
problem noted by der Mouse.
- use offsetof() to determine # of fields to calculate in initial
loop, rather than hard-coding in `52 fields'
- improve comments.
fragment synchronously, update the vnode's size before doing the flush.
otherwise we might only write part of the data and cause softdep's
accounting to get out of sync. fixes PR 14201.
many thanks to enami for figuring out what was going on.
spotted by Nathan Williams.
while I'm here, move an splbio() so that we don't return without
splx()ing it if there's an error, and don't bother calling the
pager put if the vnode has no pages.
- don't both updating fs->fs_cgrotor, since it's actually not used in
the kernel. from Manuel Bouyer in [kern/3389]
- when examining cylinder groups from startcg to startcg-1 (wrapping
at fs->fs_ncg), there's no need to check startcg at the end as well
as the start...
- highlight in the struct fs declaration that fs_cgrotor is UNUSED
- remove special treatment of pager_map mappings in pmaps. this is
required now, since I've removed the globals that expose the address range.
pager_map now uses pmap_kenter_pa() instead of pmap_enter(), so there's
no longer any need to special-case it.
- eliminate struct uvm_vnode by moving its fields into struct vnode.
- rewrite the pageout path. the pager is now responsible for handling the
high-level requests instead of only getting control after a bunch of work
has already been done on its behalf. this will allow us to UBCify LFS,
which needs tighter control over its pages than other filesystems do.
writing a page to disk no longer requires making it read-only, which
allows us to write wired pages without causing all kinds of havoc.
- use a new PG_PAGEOUT flag to indicate that a page should be freed
on behalf of the pagedaemon when it's unlocked. this flag is very similar
to PG_RELEASED, but unlike PG_RELEASED, PG_PAGEOUT can be cleared if the
pageout fails due to eg. an indirect-block buffer being locked.
this allows us to remove the "version" field from struct vm_page,
and together with shrinking "loan_count" from 32 bits to 16,
struct vm_page is now 4 bytes smaller.
- no longer use PG_RELEASED for swap-backed pages. if the page is busy
because it's being paged out, we can't release the swap slot to be
reallocated until that write is complete, but unlike with vnodes we
don't keep a count of in-progress writes so there's no good way to
know when the write is done. instead, when we need to free a busy
swap-backed page, just sleep until we can get it busy ourselves.
- implement a fast-path for extending writes which allows us to avoid
zeroing new pages. this substantially reduces cpu usage.
- encapsulate the data used by the genfs code in a struct genfs_node,
which must be the first element of the filesystem-specific vnode data
for filesystems which use genfs_{get,put}pages().
- eliminate many of the UVM pagerops, since they aren't needed anymore
now that the pager "put" operation is a higher-level operation.
- enhance the genfs code to allow NFS to use the genfs_{get,put}pages
instead of a modified copy.
- clean up struct vnode by removing all the fields that used to be used by
the vfs_cluster.c code (which we don't use anymore with UBC).
- remove kmem_object and mb_object since they were useless.
instead of allocating pages to these objects, we now just allocate
pages with no object. such pages are mapped in the kernel until they
are freed, so we can use the mapping to find the page to free it.
this allows us to remove splvm() protection in several places.
The sum of all these changes improves write throughput on my
decstation 5000/200 to within 1% of the rate of NetBSD 1.5
and reduces the elapsed time for "make release" of a NetBSD 1.5
source tree on my 128MB pc to 10% less than a 1.5 kernel took.
allocate memory from kernel_map but some of the objects are freed from
interrupt context, we put objects on a queue instead of freeing them
immediately. then in softdep_process_worklist() (which is called at
least once per second from the syncer), we process that queue and
free all the objects. allocating from kernel_map instead of from kmem_map
allows us to have a much larger number of softdeps pending even in
configurations where kmem_map is relatively small.
adjusted via sysctl. file systems that have hash tables which are
sized based on the value of this variable now resize those hash tables
using the new value. the max number of FFS softdeps is also recalculated.
convert various file systems to use the <sys/queue.h> macros for
their hash tables.
chs