On Mon, 2005-02-14 at 13:40, Andrew Morton wrote: > Badari Pulavarty <[EMAIL PROTECTED]> wrote: > > > > I see that as part of bufferheads to page association, we get a > > ref. on the page. > > > > create_empty_buffers() -> attach_page_buffers() -> page_cache_get() > > > > I also see that this reference get dropped by .. > > > > shrink_list() -> try_to_release_page() -> > > try_to_free_buffers() -> drop_buffers() -> > > __clear_page_buffers()-> page_cache_release(); > > > > So, it looks like we drop the reference on the page and disassociate > > bufferheads from the page when VM wants to re-use the page. Only other > > path, I see this can happen is through invalidate_mapping_pages(). > > Is this true ? > > > > If I do fsync(), we flush the data - still leave the page & bufferhead > > association. If I see lots of bufferheads even after fsync() is normal. > > Correct ? > > Seems about right. There's also the buffer_heads_over_limit logic in > mm/vmscan.c and fs/buffer.c. That logic has a hole in that it requires > that there be a highmem shortage before we start to reclaim the lowmem > buffer_heads, but it is somewhat helpful. >
Is there anything wrong, if we tear down bufferheads after the writepage/writepages is complete ? may be "-nobh" option for ext3 ? Even for ext2 with "-nobh" and JFS - we seem to attach buffer heads to page in __block_write_full_page() and leave them around. I was thinking, they gets tossed out after the write-out completes. No ? These bufferheads are driving me crazy :) Thanks, Badari - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
