From: Anshuman Khandual <khandual@linux.vnet.ibm.com> To: Balbir Singh <bsingharora@gmail.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Cc: hughd@google.com, dave.hansen@intel.com, aneesh.kumar@linux.vnet.ibm.com, kirill@shutemov.name, n-horiguchi@ah.jp.nec.com, mgorman@techsingularity.net, akpm@linux-foundation.org Subject: Re: [PATCH 05/10] powerpc/hugetlb: Split the function 'huge_pte_alloc' Date: Wed, 13 Apr 2016 16:38:38 +0530 [thread overview] Message-ID: <570E28B6.708@linux.vnet.ibm.com> (raw) In-Reply-To: <570BABD8.5080703@gmail.com> On 04/11/2016 07:21 PM, Balbir Singh wrote: > > > On 07/04/16 15:37, Anshuman Khandual wrote: >> Currently the function 'huge_pte_alloc' has got two versions, one for the >> BOOK3S server and the other one for the BOOK3E embedded platforms. This >> change splits only the BOOK3S server version into two parts, one for the >> ARCH_WANT_GENERAL_HUGETLB config implementation and the other one for >> everything else. This change is one of the prerequisites towards enabling >> ARCH_WANT_GENERAL_HUGETLB config option on POWER platform. >> >> Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> >> --- >> arch/powerpc/mm/hugetlbpage.c | 67 +++++++++++++++++++++++++++---------------- >> 1 file changed, 43 insertions(+), 24 deletions(-) >> >> diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c >> index d991b9e..e453918 100644 >> --- a/arch/powerpc/mm/hugetlbpage.c >> +++ b/arch/powerpc/mm/hugetlbpage.c >> @@ -59,6 +59,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) >> return __find_linux_pte_or_hugepte(mm->pgd, addr, NULL, NULL); >> } >> >> +#ifndef CONFIG_ARCH_WANT_GENERAL_HUGETLB >> static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp, >> unsigned long address, unsigned pdshift, unsigned pshift) >> { >> @@ -116,6 +117,7 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp, >> spin_unlock(&mm->page_table_lock); >> return 0; >> } >> +#endif /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */ >> >> /* >> * These macros define how to determine which level of the page table holds >> @@ -130,6 +132,7 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp, >> #endif >> >> #ifdef CONFIG_PPC_BOOK3S_64 >> +#ifndef CONFIG_ARCH_WANT_GENERAL_HUGETLB >> /* >> * At this point we do the placement change only for BOOK3S 64. This would >> * possibly work on other subarchs. >> @@ -145,32 +148,23 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz >> >> addr &= ~(sz-1); >> pg = pgd_offset(mm, addr); >> - >> - if (pshift == PGDIR_SHIFT) >> - /* 16GB huge page */ >> - return (pte_t *) pg; >> - else if (pshift > PUD_SHIFT) >> - /* >> - * We need to use hugepd table >> - */ >> + if (pshift > PUD_SHIFT) { >> hpdp = (hugepd_t *)pg; >> - else { >> - pdshift = PUD_SHIFT; >> - pu = pud_alloc(mm, pg, addr); >> - if (pshift == PUD_SHIFT) >> - return (pte_t *)pu; >> - else if (pshift > PMD_SHIFT) >> - hpdp = (hugepd_t *)pu; >> - else { >> - pdshift = PMD_SHIFT; >> - pm = pmd_alloc(mm, pu, addr); >> - if (pshift == PMD_SHIFT) >> - /* 16MB hugepage */ >> - return (pte_t *)pm; >> - else >> - hpdp = (hugepd_t *)pm; >> - } >> + goto hugepd_search; >> } >> + >> + pdshift = PUD_SHIFT; >> + pu = pud_alloc(mm, pg, addr); >> + if (pshift > PMD_SHIFT) { >> + hpdp = (hugepd_t *)pu; >> + goto hugepd_search; >> + } >> + >> + pdshift = PMD_SHIFT; >> + pm = pmd_alloc(mm, pu, addr); >> + hpdp = (hugepd_t *)pm; >> + >> +hugepd_search: >> if (!hpdp) >> return NULL; >> >> @@ -182,6 +176,31 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz >> return hugepte_offset(*hpdp, addr, pdshift); >> } >> >> +#else /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */ >> +pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz) > > This is confusing, aren't we using the one from mm/hugetlb.c? We are using huge_pte_alloc() from mm/hugetlb.c only when we have CONFIG_ARCH_WANT_GENERAL_HUGETLB enabled. For every thing else we use the definition here for BOOK3S platforms. > >> +{ >> + pgd_t *pg; >> + pud_t *pu; >> + pmd_t *pm; >> + unsigned pshift = __ffs(sz); >> + >> + addr &= ~(sz-1); > > Am I reading this right? Shouldn't this be addr &= ~(1 << pshift - 1) Both are same. __ffs() computes the __ilog2 of the size and arrives at the page shift. Here we use the size directly instead.
WARNING: multiple messages have this Message-ID (diff)
From: Anshuman Khandual <khandual@linux.vnet.ibm.com> To: Balbir Singh <bsingharora@gmail.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Cc: hughd@google.com, dave.hansen@intel.com, aneesh.kumar@linux.vnet.ibm.com, kirill@shutemov.name, n-horiguchi@ah.jp.nec.com, mgorman@techsingularity.net, akpm@linux-foundation.org Subject: Re: [PATCH 05/10] powerpc/hugetlb: Split the function 'huge_pte_alloc' Date: Wed, 13 Apr 2016 16:38:38 +0530 [thread overview] Message-ID: <570E28B6.708@linux.vnet.ibm.com> (raw) In-Reply-To: <570BABD8.5080703@gmail.com> On 04/11/2016 07:21 PM, Balbir Singh wrote: > > > On 07/04/16 15:37, Anshuman Khandual wrote: >> Currently the function 'huge_pte_alloc' has got two versions, one for the >> BOOK3S server and the other one for the BOOK3E embedded platforms. This >> change splits only the BOOK3S server version into two parts, one for the >> ARCH_WANT_GENERAL_HUGETLB config implementation and the other one for >> everything else. This change is one of the prerequisites towards enabling >> ARCH_WANT_GENERAL_HUGETLB config option on POWER platform. >> >> Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> >> --- >> arch/powerpc/mm/hugetlbpage.c | 67 +++++++++++++++++++++++++++---------------- >> 1 file changed, 43 insertions(+), 24 deletions(-) >> >> diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c >> index d991b9e..e453918 100644 >> --- a/arch/powerpc/mm/hugetlbpage.c >> +++ b/arch/powerpc/mm/hugetlbpage.c >> @@ -59,6 +59,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) >> return __find_linux_pte_or_hugepte(mm->pgd, addr, NULL, NULL); >> } >> >> +#ifndef CONFIG_ARCH_WANT_GENERAL_HUGETLB >> static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp, >> unsigned long address, unsigned pdshift, unsigned pshift) >> { >> @@ -116,6 +117,7 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp, >> spin_unlock(&mm->page_table_lock); >> return 0; >> } >> +#endif /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */ >> >> /* >> * These macros define how to determine which level of the page table holds >> @@ -130,6 +132,7 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp, >> #endif >> >> #ifdef CONFIG_PPC_BOOK3S_64 >> +#ifndef CONFIG_ARCH_WANT_GENERAL_HUGETLB >> /* >> * At this point we do the placement change only for BOOK3S 64. This would >> * possibly work on other subarchs. >> @@ -145,32 +148,23 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz >> >> addr &= ~(sz-1); >> pg = pgd_offset(mm, addr); >> - >> - if (pshift == PGDIR_SHIFT) >> - /* 16GB huge page */ >> - return (pte_t *) pg; >> - else if (pshift > PUD_SHIFT) >> - /* >> - * We need to use hugepd table >> - */ >> + if (pshift > PUD_SHIFT) { >> hpdp = (hugepd_t *)pg; >> - else { >> - pdshift = PUD_SHIFT; >> - pu = pud_alloc(mm, pg, addr); >> - if (pshift == PUD_SHIFT) >> - return (pte_t *)pu; >> - else if (pshift > PMD_SHIFT) >> - hpdp = (hugepd_t *)pu; >> - else { >> - pdshift = PMD_SHIFT; >> - pm = pmd_alloc(mm, pu, addr); >> - if (pshift == PMD_SHIFT) >> - /* 16MB hugepage */ >> - return (pte_t *)pm; >> - else >> - hpdp = (hugepd_t *)pm; >> - } >> + goto hugepd_search; >> } >> + >> + pdshift = PUD_SHIFT; >> + pu = pud_alloc(mm, pg, addr); >> + if (pshift > PMD_SHIFT) { >> + hpdp = (hugepd_t *)pu; >> + goto hugepd_search; >> + } >> + >> + pdshift = PMD_SHIFT; >> + pm = pmd_alloc(mm, pu, addr); >> + hpdp = (hugepd_t *)pm; >> + >> +hugepd_search: >> if (!hpdp) >> return NULL; >> >> @@ -182,6 +176,31 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz >> return hugepte_offset(*hpdp, addr, pdshift); >> } >> >> +#else /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */ >> +pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz) > > This is confusing, aren't we using the one from mm/hugetlb.c? We are using huge_pte_alloc() from mm/hugetlb.c only when we have CONFIG_ARCH_WANT_GENERAL_HUGETLB enabled. For every thing else we use the definition here for BOOK3S platforms. > >> +{ >> + pgd_t *pg; >> + pud_t *pu; >> + pmd_t *pm; >> + unsigned pshift = __ffs(sz); >> + >> + addr &= ~(sz-1); > > Am I reading this right? Shouldn't this be addr &= ~(1 << pshift - 1) Both are same. __ffs() computes the __ilog2 of the size and arrives at the page shift. Here we use the size directly instead. -- 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>
next prev parent reply other threads:[~2016-04-13 11:09 UTC|newest] Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-04-07 5:37 [PATCH 00/10] Enable HugeTLB page migration on POWER Anshuman Khandual 2016-04-07 5:37 ` Anshuman Khandual 2016-04-07 5:37 ` [PATCH 01/10] mm/mmap: Replace SHM_HUGE_MASK with MAP_HUGE_MASK inside mmap_pgoff Anshuman Khandual 2016-04-07 5:37 ` Anshuman Khandual 2016-04-07 8:28 ` Balbir Singh 2016-04-07 8:28 ` Balbir Singh 2016-04-13 7:54 ` Michal Hocko 2016-04-13 7:54 ` Michal Hocko 2016-04-07 5:37 ` [PATCH 02/10] mm/hugetlb: Add PGD based implementation awareness Anshuman Khandual 2016-04-07 5:37 ` Anshuman Khandual 2016-04-07 9:04 ` Balbir Singh 2016-04-07 9:04 ` Balbir Singh 2016-04-11 5:25 ` Anshuman Khandual 2016-04-11 5:25 ` Anshuman Khandual 2016-04-11 6:10 ` Anshuman Khandual 2016-04-11 6:10 ` Anshuman Khandual 2016-04-07 5:37 ` [PATCH 03/10] mm/hugetlb: Protect follow_huge_(pud|pgd) functions from race Anshuman Khandual 2016-04-07 5:37 ` Anshuman Khandual 2016-04-07 9:16 ` kbuild test robot 2016-04-18 8:44 ` Anshuman Khandual 2016-04-18 8:44 ` Anshuman Khandual 2016-04-07 9:26 ` Balbir Singh 2016-04-07 9:26 ` Balbir Singh 2016-04-11 5:39 ` Anshuman Khandual 2016-04-11 5:39 ` Anshuman Khandual 2016-04-11 12:46 ` Balbir Singh 2016-04-11 12:46 ` Balbir Singh 2016-04-07 9:34 ` kbuild test robot 2016-04-11 6:04 ` Anshuman Khandual 2016-04-11 6:04 ` Anshuman Khandual 2016-04-18 8:42 ` Anshuman Khandual 2016-04-18 8:42 ` Anshuman Khandual 2016-04-07 5:37 ` [PATCH 04/10] powerpc/hugetlb: Add ABI defines for MAP_HUGE_16MB and MAP_HUGE_16GB Anshuman Khandual 2016-04-07 5:37 ` Anshuman Khandual 2016-04-07 5:37 ` [PATCH 05/10] powerpc/hugetlb: Split the function 'huge_pte_alloc' Anshuman Khandual 2016-04-07 5:37 ` Anshuman Khandual 2016-04-11 13:51 ` Balbir Singh 2016-04-11 13:51 ` Balbir Singh 2016-04-13 11:08 ` Anshuman Khandual [this message] 2016-04-13 11:08 ` Anshuman Khandual 2016-04-07 5:37 ` [PATCH 06/10] powerpc/hugetlb: Split the function 'huge_pte_offset' Anshuman Khandual 2016-04-07 5:37 ` Anshuman Khandual 2016-04-07 5:37 ` [PATCH 07/10] powerpc/hugetlb: Prepare arch functions for ARCH_WANT_GENERAL_HUGETLB Anshuman Khandual 2016-04-07 5:37 ` Anshuman Khandual 2016-04-07 5:37 ` [PATCH 08/10] powerpc/hugetlb: Selectively enable ARCH_WANT_GENERAL_HUGETLB Anshuman Khandual 2016-04-07 5:37 ` Anshuman Khandual 2016-04-07 5:37 ` [PATCH 09/10] powerpc/hugetlb: Selectively enable ARCH_ENABLE_HUGEPAGE_MIGRATION Anshuman Khandual 2016-04-07 5:37 ` Anshuman Khandual 2016-04-07 5:37 ` [PATCH 10/10] selfttest/powerpc: Add memory page migration tests Anshuman Khandual 2016-04-07 5:37 ` Anshuman Khandual 2016-04-18 8:52 ` [PATCH 00/10] Enable HugeTLB page migration on POWER Anshuman Khandual 2016-04-18 8:52 ` Anshuman Khandual
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