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dkim=pass header.d=oracle.com header.s=corp-2021-07-09 header.b=WBcSlvGi; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=mbcq63R7; spf=none (imf10.hostedemail.com: domain of mike.kravetz@oracle.com has no SPF policy when checking 205.220.165.32) smtp.mailfrom=mike.kravetz@oracle.com; dmarc=pass (policy=none) header.from=oracle.com X-Rspamd-Queue-Id: 591CEC000A X-Stat-Signature: 7q5a1j3irsxyky9e48iezhh4kznwmhm3 X-Rspamd-Server: rspam04 X-HE-Tag: 1641491024-142541 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 1/5/22 15:56, Andrew Morton wrote: > On Tue, 4 Jan 2022 14:35:34 -0800 Axel Rasmussen wrote: > >> On Mon, Jan 3, 2022 at 6:17 PM Mike Kravetz wrote: >>> >>> The message for commit f5c73297181c ("userfaultfd/selftests: fix hugetlb >>> area allocations") says there is no need to create a hugetlb file in the >>> non-shared testing case. However, the commit did not actually change >>> the code to prevent creation of the file. >>> >>> While it is technically true that there is no need to create and use a >>> hugetlb file in the case of non-shared-testing, it is useful. This is >>> because 'hole punching' of a hugetlb file has the potentially incorrect >>> side effect of also removing pages from private mappings. The >>> userfaultfd test relies on this side effect for removing pages from the >>> destination buffer during rounds of stress testing. >>> >>> Remove the incomplete code that was added to deal with no hugetlb file. >>> Just keep the code that prevents reserves from being created for the >>> destination area. >>> >>> *alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE, >>> - map_shared ? MAP_SHARED : >>> - MAP_PRIVATE | MAP_HUGETLB | >>> + (map_shared ? MAP_SHARED : MAP_PRIVATE) | >>> + MAP_HUGETLB | >>> (*alloc_area == area_src ? 0 : MAP_NORESERVE), >>> - huge_fd, >>> - *alloc_area == area_src ? 0 : nr_pages * page_size); >>> + huge_fd, *alloc_area == area_src ? 0 : >>> + nr_pages * page_size); >> >> Sorry to nitpick, but I think it was slightly more readable when the >> ternary was all on one line. > > When you have that many arguments I think it's clearer to put one per > line, viz. > > *alloc_area = mmap(NULL, > nr_pages * page_size, > PROT_READ | PROT_WRITE, > (map_shared ? MAP_SHARED : MAP_PRIVATE) | > MAP_HUGETLB | > (*alloc_area == area_src ? 0 : MAP_NORESERVE), > huge_fd, > *alloc_area == area_src ? 0 : nr_pages * page_size); > > > But whatever... I agree, and also agree with Axel's comment about keeping the ternary all on one line. However, there are examples of breaking both these conventions throughout the file. My intention here was just to clean up the mess I created with the previous patch. As such, I would prefer to leave this patch as is. If someone really wants this modified, I will. However, IMO if we make this one call easier to read, we should use the same convention throughout the file. I can do that as well, but would prefer to first try to enable using mremap with hugetlb within the test. -- Mike Kravetz