On Thu 26-03-20 05:24:29, Matthew Wilcox wrote: > From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> > > By moving PG_writeback down into the low bits of the page flags, we can > use clear_bit_unlock_is_negative_byte() for writeback as well as the > lock bit. wake_up_page() then has no more callers. Given the other > code being executed between the clear and the test, this is not going > to be as dramatic a win as it was for PageLocked, but symmetry between > the two is nice and lets us remove some code. > > Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> The patch looks good to me. Just one nit: > + VM_BUG_ON_PAGE(!PageWriteback(page), page); > + if (__clear_page_writeback(page)) > + wake_up_page_bit(page, PG_writeback); Since __clear_page_writeback() isn't really prepared for PageWriteback() not being set, can we move the VM_BUG_ON_PAGE() there? Otherwise feel free to add: Reviewed-by: Jan Kara <jack@xxxxxxx> Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
