On 2016/7/12 23:35, Catalin Marinas wrote: > On Mon, Jul 11, 2016 at 08:43:32PM +0800, Leizhen (ThunderTown) wrote: >> On 2016/7/9 0:13, Catalin Marinas wrote: >>> On Fri, Jul 08, 2016 at 11:24:26PM +0800, Leizhen (ThunderTown) wrote: >>>> On 2016/7/8 21:54, Catalin Marinas wrote: >>>>> ------------8<---------------- >>>>> diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c >>>>> index dbd12ea8ce68..c753fa804165 100644 >>>>> --- a/arch/arm64/mm/flush.c >>>>> +++ b/arch/arm64/mm/flush.c >>>>> @@ -75,7 +75,8 @@ void __sync_icache_dcache(pte_t pte, unsigned long addr) >>>>> if (!page_mapping(page)) >>>>> return; >>>>> >>>>> - if (!test_and_set_bit(PG_dcache_clean, &page->flags)) >>>>> + if (!test_and_set_bit(PG_dcache_clean, &page->flags) || >>>>> + PageDirty(page)) >>>>> sync_icache_aliases(page_address(page), >>>>> PAGE_SIZE << compound_order(page)); >>>>> else if (icache_is_aivivt()) >>>>> ----------------8<--------------------- Hi, Catalin: Do you plan to send this patch? My colleagues told me that if our patches are quite different, it should be Signed-off-by you.
I searched all Linux source code, __sync_icache_dcache is only called by set_pte_at, and some check conditions(especially pte_exec) will limit its impact. if (pte_user(pte) && pte_exec(pte) && !pte_special(pte)) __sync_icache_dcache(pte, addr); >>>>> >>>>> BTW, can you make your tests (source) available somewhere? >>>> >>>> Both cases worked well with this patch. >>> >>> Now I'm even more confused ;). IIUC, after an msync() in user space we >>> should flush the pages to disk via write_cache_pages(). This function >>> calls clear_page_dirty_for_io() after which PageDirty() is no longer >>> true. I can't tell how a subsequent mmap() can see the written pages as >>> dirty. >> >> As my tracing, both cases invoked empty function. >> >> int vfs_fsync_range(struct file *file, loff_t start, loff_t end, int >> datasync) >> ...... >> return file->f_op->fsync(file, start, end, datasync); >> } >> >> const struct file_operations hugetlbfs_file_operations = { >> .fsync = noop_fsync, >> >> static const struct file_operations shmem_file_operations = { >> .mmap = shmem_mmap, >> #ifdef CONFIG_TMPFS >> .fsync = noop_fsync, > > I was referring to standard filesystem (e.g. ext4) writes where, IIUC, > the PageDirty() status is cleared after I/O but it's not necessarily > removed from the page cache. >