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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 88C2EA000F X-Stat-Signature: tgss7cc8seujdd74uxmzmtw4eugioyoe X-Rspam-User: X-HE-Tag: 1733211991-762710 X-HE-Meta: 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 raTsNmfo v2yrLdl2uq9GiUM7Qjgkyt059bA9VAVOVU9H6sg4EI7CgtI/K27CzQmgPYz/RodKuD4cC/5Qt0xJ2hlfAVfxKUFjZKzZ6UP4HrMt3DHza0SQ6gblouRd0tE9c13xJozdvR/VN6uDkUjLy1I/T0ELiP5mjKnlU9bF4rFiG0SCsbndhlZGXg38c1yXQgqBquMbwFGDfDjFPLwVkeVGIjwovBlJoOwuhJFSIKw//Q9udXnGyOiMWVH6MeJPgtgdITcfLUArwkb55yZnWd/nblpdKK72i9asimOgmXdY5gR7giTDKjxMsuNmCUYtaWYk3N0e9FI9RM3ZpiADk64ADmFAFQdhl1LUoaD/Ekk+fw1aAhm0RzsWKHiT94uW1DiilJoHLStOFi6/LQsMCK00= 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: List-Subscribe: List-Unsubscribe: On 12/3/24 08:59, Muchun Song wrote: > > >> On Dec 3, 2024, at 10:32, Anshuman Khandual wrote: >> >> The HugeTLB order check against __NR_USED_SUBPAGE is required only when >> HUGETLB_PAGE_OPTIMIZE_VMEMMAP is enabled. Hence BUG_ON() trigger should >> happen only when applicable. >> >> Cc: Muchun Song >> Cc: Andrew Morton >> Cc: Oscar Salvador >> Cc: linux-mm@kvack.org >> Cc: linux-kernel@vger.kernel.org >> Signed-off-by: Anshuman Khandual >> --- >> This patch applies on v6.13-rc1 >> >> Changes in V2: >> >> - Fixed #ifdef with CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP per Oscar >> >> Changes in V1: >> >> https://lore.kernel.org/all/20241202090728.78935-1-anshuman.khandual@arm.com/ >> >> mm/hugetlb.c | 6 ++++-- >> 1 file changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/mm/hugetlb.c b/mm/hugetlb.c >> index ea2ed8e301ef..e6a5b21e3578 100644 >> --- a/mm/hugetlb.c >> +++ b/mm/hugetlb.c >> @@ -4513,11 +4513,13 @@ void __init hugetlb_add_hstate(unsigned int order) >> struct hstate *h; >> unsigned long i; >> >> - if (size_to_hstate(PAGE_SIZE << order)) { >> + if (size_to_hstate(PAGE_SIZE << order)) >> return; >> - } >> + >> BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE); >> +#ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP >> BUG_ON(order < order_base_2(__NR_USED_SUBPAGE)); > > Hi Anshuman, > > __NR_USED_SUBPAGE indicates how many struct pages are used to store > extra metadata for a HugeTLB page. So we need to make sure the order > of a HugeTLB page should be bigger than or equal to order_base_2(__NR_USED_SUBPAGE). > So It is not related to HVO. I don't think the changes make sense. I did think about that but order_base_2(__NR_USED_SUBPAGE) actually turns out to be just 2 as __NR_USED_SUBPAGE is 3. Would not HugeTLB size be always greater than four base pages in reality, thus making this BUG_ON() check just redundant ? > > Thanks. > >> +#endif >> h = &hstates[hugetlb_max_hstate++]; >> __mutex_init(&h->resize_lock, "resize mutex", &h->resize_key); >> h->order = order; >> -- >> 2.30.2 >> >