From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: Christophe Leroy <christophe.leroy@c-s.fr>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
aneesh.kumar@linux.vnet.ibm.com
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v4 15/20] powerpc/mm: Avoid useless lock with single page fragments
Date: Wed, 19 Sep 2018 08:26:26 +0530 [thread overview]
Message-ID: <78cb82d6-1a13-150d-9daa-021bd2f98e7a@linux.ibm.com> (raw)
In-Reply-To: <7efec0c76fa692513c806871151a7ae20e99fe05.1537288312.git.christophe.leroy@c-s.fr>
On 9/18/18 10:27 PM, Christophe Leroy wrote:
> There is no point in taking the page table lock as
> pte_frag is always NULL when we have only one fragment.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
> arch/powerpc/mm/pgtable-frag.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/powerpc/mm/pgtable-frag.c b/arch/powerpc/mm/pgtable-frag.c
> index bc924822dcd6..ab4910e92aaf 100644
> --- a/arch/powerpc/mm/pgtable-frag.c
> +++ b/arch/powerpc/mm/pgtable-frag.c
> @@ -85,6 +85,9 @@ static pte_t *get_pte_from_cache(struct mm_struct *mm)
> {
> void *pte_frag, *ret;
>
> + if (PTE_FRAG_NR == 1)
> + return NULL;
> +
> spin_lock(&mm->page_table_lock);
> ret = mm->context.pte_frag;
> if (ret) {
>
May be update get_pmd_from_cache too?
-aneesh
next prev parent reply other threads:[~2018-09-19 3:35 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-18 16:57 [PATCH v4 00/20] Implement use of HW assistance on TLB table walk on 8xx Christophe Leroy
2018-09-18 16:57 ` [PATCH v4 01/20] Revert "powerpc/8xx: Use L1 entry APG to handle _PAGE_ACCESSED for CONFIG_SWAP" Christophe Leroy
2018-09-18 16:57 ` [PATCH v4 02/20] powerpc/code-patching: add a helper to get the address of a patch_site Christophe Leroy
2018-09-18 16:57 ` [PATCH v4 03/20] powerpc/8xx: Use patch_site for memory setup patching Christophe Leroy
2018-09-18 16:57 ` [PATCH v4 04/20] powerpc/8xx: Use patch_site for perf counters setup Christophe Leroy
2018-09-18 16:57 ` [PATCH v4 05/20] powerpc/8xx: Move SW perf counters in first 32kb of memory Christophe Leroy
2018-09-18 16:57 ` [PATCH v4 06/20] powerpc/8xx: Temporarily disable 16k pages and 512k hugepages Christophe Leroy
2018-09-18 16:57 ` [PATCH v4 07/20] powerpc/mm: Use hardware assistance in TLB handlers on the 8xx Christophe Leroy
2018-09-18 16:57 ` [PATCH v4 08/20] powerpc/mm: Enable 512k hugepage support with HW assistance " Christophe Leroy
2018-09-18 16:57 ` [PATCH v4 09/20] powerpc/8xx: don't use r12/SPRN_SPRG_SCRATCH2 in TLB Miss handlers Christophe Leroy
2018-09-18 16:57 ` [PATCH v4 10/20] powerpc/8xx: regroup TLB handler routines Christophe Leroy
2018-09-18 16:57 ` [PATCH v4 11/20] powerpc/mm: don't use pte_alloc_one_kernel() before slab is available Christophe Leroy
2018-09-18 16:57 ` [PATCH v4 12/20] powerpc/mm: inline pte_alloc_one() and pte_alloc_one_kernel() in PPC32 Christophe Leroy
2018-09-18 16:57 ` [PATCH v4 13/20] powerpc/book3s32: Remove CONFIG_BOOKE dependent code Christophe Leroy
2018-09-18 16:57 ` [PATCH v4 14/20] powerpc/mm: Move pte_fragment_alloc() to a common location Christophe Leroy
2018-09-18 16:57 ` [PATCH v4 15/20] powerpc/mm: Avoid useless lock with single page fragments Christophe Leroy
2018-09-19 2:56 ` Aneesh Kumar K.V [this message]
2018-09-25 16:49 ` Christophe LEROY
2018-09-18 16:57 ` [PATCH v4 16/20] powerpc/mm: Extend pte_fragment functionality to nohash/32 Christophe Leroy
2018-09-19 3:03 ` Aneesh Kumar K.V
2018-09-25 16:48 ` Christophe LEROY
2018-09-18 16:57 ` [PATCH v4 17/20] powerpc/8xx: Remove PTE_ATOMIC_UPDATES Christophe Leroy
2018-09-18 16:57 ` [PATCH v4 18/20] powerpc/mm: reintroduce 16K pages with HW assistance on 8xx Christophe Leroy
2018-09-18 16:57 ` [PATCH v4 19/20] powerpc/nohash32: allow setting GUARDED attribute in the PMD directly Christophe Leroy
2018-09-18 16:57 ` [PATCH v4 20/20] powerpc/8xx: set " Christophe Leroy
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