| Message ID | 20200513135742.102064-1-hushijie3@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v4] hugetlbfs: Get unmapped area below TASK_UNMAPPED_BASE for hugetlbfs | expand |
Hi Shijie,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on linus/master]
[also build test ERROR on v5.7-rc5 next-20200512]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
url: https://github.com/0day-ci/linux/commits/Shijie-Hu/hugetlbfs-Get-unmapped-area-below-TASK_UNMAPPED_BASE-for-hugetlbfs/20200513-221024
base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 24085f70a6e1b0cb647ec92623284641d8270637
config: riscv-allyesconfig (attached as .config)
compiler: riscv64-linux-gcc (GCC) 9.3.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day GCC_VERSION=9.3.0 make.cross ARCH=riscv
If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
fs/hugetlbfs/inode.c: In function 'hugetlb_get_unmapped_area':
>> fs/hugetlbfs/inode.c:268:31: error: 'arch_get_unmapped_area' undeclared (first use in this function); did you mean 'thp_get_unmapped_area'?
268 | if (mm->get_unmapped_area == arch_get_unmapped_area)
| ^~~~~~~~~~~~~~~~~~~~~~
| thp_get_unmapped_area
fs/hugetlbfs/inode.c:268:31: note: each undeclared identifier is reported only once for each function it appears in
vim +268 fs/hugetlbfs/inode.c
240
241 static unsigned long
242 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
243 unsigned long len, unsigned long pgoff, unsigned long flags)
244 {
245 struct mm_struct *mm = current->mm;
246 struct vm_area_struct *vma;
247 struct hstate *h = hstate_file(file);
248
249 if (len & ~huge_page_mask(h))
250 return -EINVAL;
251 if (len > TASK_SIZE)
252 return -ENOMEM;
253
254 if (flags & MAP_FIXED) {
255 if (prepare_hugepage_range(file, addr, len))
256 return -EINVAL;
257 return addr;
258 }
259
260 if (addr) {
261 addr = ALIGN(addr, huge_page_size(h));
262 vma = find_vma(mm, addr);
263 if (TASK_SIZE - len >= addr &&
264 (!vma || addr + len <= vm_start_gap(vma)))
265 return addr;
266 }
267
> 268 if (mm->get_unmapped_area == arch_get_unmapped_area)
269 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
270 pgoff, flags);
271 return hugetlb_get_unmapped_area_topdown(file, addr, len,
272 pgoff, flags);
273 }
274 #endif
275
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 991c60c7ffe0..bbee893e88da 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -191,13 +191,60 @@ static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma) #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA static unsigned long +hugetlb_get_unmapped_area_bottomup(struct file *file, unsigned long addr, + unsigned long len, unsigned long pgoff, unsigned long flags) +{ + struct hstate *h = hstate_file(file); + struct vm_unmapped_area_info info; + + info.flags = 0; + info.length = len; + info.low_limit = current->mm->mmap_base; + info.high_limit = TASK_SIZE; + info.align_mask = PAGE_MASK & ~huge_page_mask(h); + info.align_offset = 0; + return vm_unmapped_area(&info); +} + +static unsigned long +hugetlb_get_unmapped_area_topdown(struct file *file, unsigned long addr, + unsigned long len, unsigned long pgoff, unsigned long flags) +{ + struct hstate *h = hstate_file(file); + struct vm_unmapped_area_info info; + + info.flags = VM_UNMAPPED_AREA_TOPDOWN; + info.length = len; + info.low_limit = max(PAGE_SIZE, mmap_min_addr); + info.high_limit = current->mm->mmap_base; + info.align_mask = PAGE_MASK & ~huge_page_mask(h); + info.align_offset = 0; + addr = vm_unmapped_area(&info); + + /* + * A failed mmap() very likely causes application failure, + * so fall back to the bottom-up function here. This scenario + * can happen with large stack limits and large mmap() + * allocations. + */ + if (unlikely(offset_in_page(addr))) { + VM_BUG_ON(addr != -ENOMEM); + info.flags = 0; + info.low_limit = current->mm->mmap_base; + info.high_limit = TASK_SIZE; + addr = vm_unmapped_area(&info); + } + + return addr; +} + +static unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { struct mm_struct *mm = current->mm; struct vm_area_struct *vma; struct hstate *h = hstate_file(file); - struct vm_unmapped_area_info info; if (len & ~huge_page_mask(h)) return -EINVAL; @@ -218,13 +265,11 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr, return addr; } - info.flags = 0; - info.length = len; - info.low_limit = TASK_UNMAPPED_BASE; - info.high_limit = TASK_SIZE; - info.align_mask = PAGE_MASK & ~huge_page_mask(h); - info.align_offset = 0; - return vm_unmapped_area(&info); + if (mm->get_unmapped_area == arch_get_unmapped_area) + return hugetlb_get_unmapped_area_bottomup(file, addr, len, + pgoff, flags); + return hugetlb_get_unmapped_area_topdown(file, addr, len, + pgoff, flags); } #endif
Here is a final patch to solve that hugetlb_get_unmapped_area() can't get unmapped area below mmap base for huge pages based on a few previous discussions and patches from me. I'm so sorry. When sending v2 and v3 patches, I forget to cc: linux-mm@kvack.org and linux-kernel@vger.kernel.org. No records of these two patches found on the https://lkml.org/lkml/. Patch V1: https://lkml.org/lkml/2020/4/27/440 Changes in V2: * Follow Mike's suggestions, move hugetlb_get_unmapped_area() routines from "fs/hugetlbfs/inode.c" to "arch/arm64/mm/hugetlbpage.c", without changing core code. * Add mmap_is_legacy() function, and only fall back to the bottom-up function on no-legacy mode. Changes in V3: * Add *bottomup() and *topdown() two function, and check if mm->get_unmapped_area is equal to arch_get_unmapped_area() instead of checking mmap_is_legacy() to determine which function should be used. Changes in V4: * Follow the suggestions of Will and Mike, move back this patch to core code. ------ In a 32-bit program, running on arm64 architecture. When the address space below mmap base is completely exhausted, shmat() for huge pages will return ENOMEM, but shmat() for normal pages can still success on no-legacy mode. This seems not fair. For normal pages, get_unmapped_area() calling flows are: => mm->get_unmapped_area() if on legacy mode, => arch_get_unmapped_area() => vm_unmapped_area() if on no-legacy mode, => arch_get_unmapped_area_topdown() => vm_unmapped_area() For huge pages, get_unmapped_area() calling flows are: => file->f_op->get_unmapped_area() => hugetlb_get_unmapped_area() => vm_unmapped_area() To solve this issue, we only need to make hugetlb_get_unmapped_area() take the same way as mm->get_unmapped_area(). Add *bottomup() and *topdown() two functions, and check current mm->get_unmapped_area() to decide which one to use. If mm->get_unmapped_area is equal to arch_get_unmapped_area(), hugetlb_get_unmapped_area() calls bottomup routine, otherwise calls topdown routine. Signed-off-by: Shijie Hu <hushijie3@huawei.com> --- fs/hugetlbfs/inode.c | 61 +++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 53 insertions(+), 8 deletions(-)