Re: [PATCH v5 06/25] mm: Add PG_ARCH_2 page flag
From: Andrew Morton <akpm@linux-foundation.org>
Date: 2020-06-24 18:33:11
Also in:
linux-arch, linux-mm
On Wed, 24 Jun 2020 18:52:25 +0100 Catalin Marinas [off-list ref] wrote:
quoted hunk ↗ jump to hunk
From: Steven Price <steven.price@arm.com> For arm64 MTE support it is necessary to be able to mark pages that contain user space visible tags that will need to be saved/restored e.g. when swapped out. To support this add a new arch specific flag (PG_ARCH_2) that arch code can opt into using ARCH_USES_PG_ARCH_2. ...--- a/fs/proc/page.c +++ b/fs/proc/page.c@@ -217,6 +217,9 @@ u64 stable_page_flags(struct page *page) u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2); u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1); u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1); +#ifdef CONFIG_ARCH_USES_PG_ARCH_2 + u |= kpf_copy_bit(k, KPF_ARCH_2, PG_arch_2); +#endif
Do we need CONFIG_ARCH_USES_PG_ARCH_2? What would be the downside to giving every architecture a PG_arch_2, but only arm64 uses it (at present)? _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel