On Thu 17-09-09 18:11:27, Boaz Harrosh wrote: > On 09/17/2009 04:56 PM, Jan Kara wrote: > > Hi, > > > > during my page_mkwrite() work, I've looked at who uses nobh_ versions of > > various functions in fs/buffer.c. It seems only ext2 and jfs use them. ext3 > > uses them only from writepage() (which means we needn't attach buffers to a > > page when it was written via mmap in writeback mode) and ext4 tries to use > > them but in fact it's nop because it always attaches buffers to the page > > earlier. So it's not really widely used, there's quite some code to support > > it (including one page flag), and it also slightly complicates my > > page_mkwrite() fixes. > > So I wanted to ask does somebody actually remember what it is good for? > > Buffer heads obviously consume some memory so was that the reason? OTOH we > > have to map the page whenever we write to it or send it to disk via > > writepage(). > > > > Honza > > I'm currently using nobh_truncate_page() in fs/exofs/inode.c::exofs_truncate(). > > Though, I suspect that once I do the conversion to Nick's: > "[patch 00/11] new truncate sequence" > and it is submitted, that use will disappear. Yeah, actually with page_mkwrite patches I've just sent, this would definitely go away so this isn't a use I'm too much worried about ;). But thanks for info anyway. Honza -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
