Re: [PATCH 70/71] mm: get rid of PAGE_CACHE_* and page_cache_{get,release} macros
From: Guenter Roeck <linux@roeck-us.net>
Date: 2016-03-20 23:59:58
Also in:
linux-fsdevel, lkml
On Sun, Mar 20, 2016 at 09:41:17PM +0300, Kirill A. Shutemov wrote:
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago
with promise that one day it will be possible to implement page cache with
bigger chunks than PAGE_SIZE.
This promise never materialized. And unlikely will.
We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_*
or PAGE_* constant should be used in a particular case, especially on the
border between fs and mm.
Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.
Let's stop pretending that pages in page cache are special. They are not.
The changes are pretty straight-forward:
- <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
- PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};
- page_cache_get() -> get_page();
- page_cache_release() -> put_page();
Signed-off-by: Kirill A. Shutemov <redacted>
---...
quoted hunk ↗ jump to hunk
extern pgoff_t linear_hugepage_index(struct vm_area_struct *vma,@@ -425,7 +425,7 @@ static inline pgoff_t linear_page_index(struct vm_area_struct *vma, return linear_hugepage_index(vma, address); pgoff = (address - vma->vm_start) >> PAGE_SHIFT; pgoff += vma->vm_pgoff; - return pgoff >> (PAGE_CACHE_SHIFT - PAGE_SHIFT); + return pgoff >> (PAGE_SHIFT - PAGE_SHIFT);
^^^^^^^^^^^^^^^^^^^^^^^^^ Guenter -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>