Messages in this thread | | | Subject | Re: Is ext3 flush data to disk when files are closed? | From | Badari Pulavarty <> | Date | Wed, 19 Oct 2005 14:11:26 -0700 |
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On Wed, 2005-10-19 at 13:00 -0700, Andrew Morton wrote: > Badari Pulavarty <pbadari@gmail.com> wrote: > > > > On Wed, 2005-10-19 at 11:31 -0400, Xin Zhao wrote: > > > As far as I know, if an application modifies a file on an ext3 file > > > ssytem, it actually change the page cache, and the dirty pages will be > > > flushed to disk by kupdate periodically. > > > > > > My question is: if a file is to be closed, but some of its data pages > > > are marked as dirty, will system block on close() and wait for dirty > > > pages being flushed to disk? If so, it seems to decrease performance > > > significantly if a lot of updates on many small files are involved. > > > > > > Can someone point me to the right place to check how it works? Thanks! > > > > On the last close() of the file, it should be flushed through .. > > > > iput_final() -> generic_drop_inode() -> write_inode_now() > > -> __writeback_single_inode() -> __sync_single_inode() > > -> do_writepages() > > The dcache's reference to the inode will prevent this from happening at > close() time. >
I thought so too, till I wrote a kprobe/systemtap script to print the callers of generic_forget_inode() earlier and saw that most of my stacks are from exit() or close().
0xffffffff801a0222 : generic_drop_inode+0x2/0x170 [] 0xffffffff8019eeb0 : iput+0x50/0x90 [] 0xffffffff8019c7bb : dput+0x1db/0x220 [] 0xffffffff80184461 : __fput+0x171/0x1e0 [] 0xffffffff801829ce : filp_close+0x6e/0x90 [] 0xffffffff801388eb : put_files_struct+0x6b/0xc0 [] 0xffffffff801392ef : do_exit+0x1ff/0xbb0 []
0xffffffff801a0222 : generic_drop_inode+0x2/0x170 [] 0xffffffff8019eeb0 : iput+0x50/0x90 [] 0xffffffff8019c7bb : dput+0x1db/0x220 [] 0xffffffff80184461 : __fput+0x171/0x1e0 [] 0xffffffff801829ce : filp_close+0x6e/0x90 [] 0xffffffff80182a90 : sys_close+0xa0/0xd0 [] 0xffffffff8010dbc2 : system_call+0x1a/0x83 []
Thanks, Badari
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