From: Peter Zijlstra <peterz@infradead.org>
To: linux-kernel@vger.kernel.org
Cc: linux-tip-commits@vger.kernel.org,
"Denis V. Lunev" <den@openvz.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
"Kiryl Shutsemau (Meta)" <kas@kernel.org>,
x86@kernel.org
Subject: Re: [tip: x86/mm] x86/mm/pat: Take cpa_lock around large-page collapse
Date: Tue, 28 Jul 2026 11:00:37 +0200 [thread overview]
Message-ID: <20260728090037.GF49951@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <178418886773.1844600.15146928511649606123.tip-bot2@tip-bot2>
On Thu, Jul 16, 2026 at 08:01:07AM -0000, tip-bot2 for Denis V. Lunev wrote:
> diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
> index e9b4083..b1e780a 100644
> --- a/arch/x86/mm/pat/set_memory.c
> +++ b/arch/x86/mm/pat/set_memory.c
> @@ -417,6 +417,8 @@ static void cpa_collapse_large_pages(struct cpa_data *cpa)
> int collapsed = 0;
> int i;
>
> + spin_lock(&cpa_lock);
> +
> if (cpa->flags & (CPA_PAGES_ARRAY | CPA_ARRAY)) {
> for (i = 0; i < cpa->numpages; i++)
> collapsed += collapse_large_pages(__cpa_addr(cpa, i),
> @@ -430,8 +432,10 @@ static void cpa_collapse_large_pages(struct cpa_data *cpa)
> collapsed += collapse_large_pages(addr, &pgtables);
> }
>
> - if (!collapsed)
> + if (!collapsed) {
> + spin_unlock(&cpa_lock);
> return;
> + }
>
> flush_tlb_all();
>
> @@ -439,6 +443,8 @@ static void cpa_collapse_large_pages(struct cpa_data *cpa)
> list_del(&ptdesc->pt_list);
> pagetable_free(ptdesc);
> }
> +
> + spin_unlock(&cpa_lock);
> }
>
> static void cpa_flush(struct cpa_data *cpa, int cache)
*groan*
Can we pretty please write it like so?
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index 1f2a2ba9ce57..f90f90bd879f 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -417,7 +417,7 @@ static void cpa_collapse_large_pages(struct cpa_data *cpa)
int collapsed = 0;
int i;
- spin_lock(&cpa_lock);
+ guard(spinlock)(&cpa_lock);
if (cpa->flags & (CPA_PAGES_ARRAY | CPA_ARRAY)) {
for (i = 0; i < cpa->numpages; i++)
@@ -432,10 +432,8 @@ static void cpa_collapse_large_pages(struct cpa_data *cpa)
collapsed += collapse_large_pages(addr, &pgtables);
}
- if (!collapsed) {
- spin_unlock(&cpa_lock);
+ if (!collapsed)
return;
- }
flush_tlb_all();
@@ -443,8 +441,6 @@ static void cpa_collapse_large_pages(struct cpa_data *cpa)
list_del(&ptdesc->pt_list);
pagetable_free(ptdesc);
}
-
- spin_unlock(&cpa_lock);
}
static void cpa_flush(struct cpa_data *cpa, int cache)
next prev parent reply other threads:[~2026-07-28 9:00 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-15 18:34 [PATCH v2] x86/mm/pat: take " Denis V. Lunev
2026-07-16 5:54 ` Mike Rapoport
2026-07-16 8:01 ` [tip: x86/mm] x86/mm/pat: Take " tip-bot2 for Denis V. Lunev
2026-07-28 9:00 ` Peter Zijlstra [this message]
2026-07-21 16:07 ` [PATCH v2] x86/mm/pat: take " Lorenzo Stoakes (ARM)
2026-07-21 17:20 ` Lorenzo Stoakes (ARM)
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