On 04/21/2016 12:06 AM, Matthew Wilcox wrote:
> On Wed, Apr 20, 2016 at 11:10:25PM -0400, Toshi Kani wrote:
>> How about moving the function (as is) to mm/huge_memory.c, rename it to
>> get_hugepage_unmapped_area(), which is defined to NULL in huge_mm.h
>> when TRANSPARENT_HUGEPAGE is unset?
>
> Great idea. Perhaps it should look something like this?
>
> unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr,
> unsigned long len, unsigned long pgoff, unsigned long flags)
> {
Might want to keep the future possibility of PUD_SIZE THP in mind?
--
Mike Kravetz
> loff_t off, off_end, off_pmd;
> unsigned long len_pmd, addr_pmd;
>
> if (addr)
> goto out;
> if (IS_DAX(filp->f_mapping->host) && !IS_ENABLED(CONFIG_FS_DAX_PMD))
> goto out;
> /* Kirill, please fill in the right condition here for THP pagecache */
>
> off = (loff_t)pgoff << PAGE_SHIFT;
> off_end = off + len;
> off_pmd = round_up(off, PMD_SIZE); /* pmd-aligned start offset */
>
> if ((off_end <= off_pmd) || ((off_end - off_pmd) < PMD_SIZE))
> goto out;
>
> len_pmd = len + PMD_SIZE;
> if ((off + len_pmd) < off)
> goto out;
>
> addr_pmd = current->mm->get_unmapped_area(filp, NULL, len_pmd,
> pgoff, flags);
> if (!IS_ERR_VALUE(addr_pmd)) {
> addr_pmd += (off - addr_pmd) & (PMD_SIZE - 1);
> return addr_pmd;
> }
> out:
> return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
> }
>
> - I deleted the check for filp == NULL. It can't be NULL ... this is a
> file_operation ;-)
> - Why is len_pmd len + PMD_SIZE instead of round_up(len, PMD_SIZE)?
> - I'm still in two minds about passing 'addr' to the first call to
> get_unmapped_area() instead of NULL.
> _______________________________________________
> Linux-nvdimm mailing list
> Linux-nvdimm@xxxxxxxxxxxx
> https://lists.01.org/mailman/listinfo/linux-nvdimm
>
--
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
