From: andrey.konovalov@linux.dev To: Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Konovalov <andreyknvl@gmail.com>, Marco Elver <elver@google.com>, Alexander Potapenko <glider@google.com>, Dmitry Vyukov <dvyukov@google.com>, Andrey Ryabinin <ryabinin.a.a@gmail.com>, kasan-dev@googlegroups.com, linux-mm@kvack.org, Vincenzo Frascino <vincenzo.frascino@arm.com>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Mark Rutland <mark.rutland@arm.com>, linux-arm-kernel@lists.infradead.org, Peter Collingbourne <pcc@google.com>, Evgenii Stepanov <eugenis@google.com>, linux-kernel@vger.kernel.org, Andrey Konovalov <andreyknvl@google.com> Subject: [PATCH v6 07/39] mm: clarify __GFP_ZEROTAGS comment Date: Mon, 24 Jan 2022 19:02:15 +0100 [thread overview] Message-ID: <cdffde013973c5634a447513e10ec0d21e8eee29.1643047180.git.andreyknvl@google.com> (raw) In-Reply-To: <cover.1643047180.git.andreyknvl@google.com> From: Andrey Konovalov <andreyknvl@google.com> __GFP_ZEROTAGS is intended as an optimization: if memory is zeroed during allocation, it's possible to set memory tags at the same time with little performance impact. Clarify this intention of __GFP_ZEROTAGS in the comment. Signed-off-by: Andrey Konovalov <andreyknvl@google.com> --- Changes v4->v5: - Mention optimization intention in the comment. --- include/linux/gfp.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/include/linux/gfp.h b/include/linux/gfp.h index 80f63c862be5..581a1f47b8a2 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -232,8 +232,10 @@ struct vm_area_struct; * * %__GFP_ZERO returns a zeroed page on success. * - * %__GFP_ZEROTAGS returns a page with zeroed memory tags on success, if - * __GFP_ZERO is set. + * %__GFP_ZEROTAGS zeroes memory tags at allocation time if the memory itself + * is being zeroed (either via __GFP_ZERO or via init_on_alloc). This flag is + * intended for optimization: setting memory tags at the same time as zeroing + * memory has minimal additional performace impact. * * %__GFP_SKIP_KASAN_POISON returns a page which does not need to be poisoned * on deallocation. Typically used for userspace pages. Currently only has an -- 2.25.1
WARNING: multiple messages have this Message-ID (diff)
From: andrey.konovalov@linux.dev To: Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Konovalov <andreyknvl@gmail.com>, Marco Elver <elver@google.com>, Alexander Potapenko <glider@google.com>, Dmitry Vyukov <dvyukov@google.com>, Andrey Ryabinin <ryabinin.a.a@gmail.com>, kasan-dev@googlegroups.com, linux-mm@kvack.org, Vincenzo Frascino <vincenzo.frascino@arm.com>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Mark Rutland <mark.rutland@arm.com>, linux-arm-kernel@lists.infradead.org, Peter Collingbourne <pcc@google.com>, Evgenii Stepanov <eugenis@google.com>, linux-kernel@vger.kernel.org, Andrey Konovalov <andreyknvl@google.com> Subject: [PATCH v6 07/39] mm: clarify __GFP_ZEROTAGS comment Date: Mon, 24 Jan 2022 19:02:15 +0100 [thread overview] Message-ID: <cdffde013973c5634a447513e10ec0d21e8eee29.1643047180.git.andreyknvl@google.com> (raw) In-Reply-To: <cover.1643047180.git.andreyknvl@google.com> From: Andrey Konovalov <andreyknvl@google.com> __GFP_ZEROTAGS is intended as an optimization: if memory is zeroed during allocation, it's possible to set memory tags at the same time with little performance impact. Clarify this intention of __GFP_ZEROTAGS in the comment. Signed-off-by: Andrey Konovalov <andreyknvl@google.com> --- Changes v4->v5: - Mention optimization intention in the comment. --- include/linux/gfp.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/include/linux/gfp.h b/include/linux/gfp.h index 80f63c862be5..581a1f47b8a2 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -232,8 +232,10 @@ struct vm_area_struct; * * %__GFP_ZERO returns a zeroed page on success. * - * %__GFP_ZEROTAGS returns a page with zeroed memory tags on success, if - * __GFP_ZERO is set. + * %__GFP_ZEROTAGS zeroes memory tags at allocation time if the memory itself + * is being zeroed (either via __GFP_ZERO or via init_on_alloc). This flag is + * intended for optimization: setting memory tags at the same time as zeroing + * memory has minimal additional performace impact. * * %__GFP_SKIP_KASAN_POISON returns a page which does not need to be poisoned * on deallocation. Typically used for userspace pages. Currently only has an -- 2.25.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-01-24 18:03 UTC|newest] Thread overview: 113+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-01-24 18:02 [PATCH v6 00/39] kasan, vmalloc, arm64: add vmalloc tagging support for SW/HW_TAGS andrey.konovalov 2022-01-24 18:02 ` andrey.konovalov 2022-01-24 18:02 ` [PATCH v6 01/39] kasan, page_alloc: deduplicate should_skip_kasan_poison andrey.konovalov 2022-01-24 18:02 ` andrey.konovalov 2022-01-24 18:02 ` [PATCH v6 02/39] kasan, page_alloc: move tag_clear_highpage out of kernel_init_free_pages andrey.konovalov 2022-01-24 18:02 ` andrey.konovalov 2022-01-24 18:02 ` [PATCH v6 03/39] kasan, page_alloc: merge kasan_free_pages into free_pages_prepare andrey.konovalov 2022-01-24 18:02 ` andrey.konovalov 2022-01-24 18:02 ` [PATCH v6 04/39] kasan, page_alloc: simplify kasan_poison_pages call site andrey.konovalov 2022-01-24 18:02 ` andrey.konovalov 2022-01-24 18:02 ` [PATCH v6 05/39] kasan, page_alloc: init memory of skipped pages on free andrey.konovalov 2022-01-24 18:02 ` andrey.konovalov 2022-01-24 18:02 ` [PATCH v6 06/39] kasan: drop skip_kasan_poison variable in free_pages_prepare andrey.konovalov 2022-01-24 18:02 ` andrey.konovalov 2022-01-24 18:02 ` andrey.konovalov [this message] 2022-01-24 18:02 ` [PATCH v6 07/39] mm: clarify __GFP_ZEROTAGS comment andrey.konovalov 2022-01-24 18:02 ` [PATCH v6 08/39] kasan: only apply __GFP_ZEROTAGS when memory is zeroed andrey.konovalov 2022-01-24 18:02 ` andrey.konovalov 2022-01-24 18:02 ` [PATCH v6 09/39] kasan, page_alloc: refactor init checks in post_alloc_hook andrey.konovalov 2022-01-24 18:02 ` andrey.konovalov 2022-01-24 18:02 ` [PATCH v6 10/39] kasan, page_alloc: merge kasan_alloc_pages into post_alloc_hook andrey.konovalov 2022-01-24 18:02 ` andrey.konovalov 2022-01-24 18:02 ` [PATCH v6 11/39] kasan, page_alloc: combine tag_clear_highpage calls in post_alloc_hook andrey.konovalov 2022-01-24 18:02 ` andrey.konovalov 2022-01-24 18:02 ` [PATCH v6 12/39] kasan, page_alloc: move SetPageSkipKASanPoison " andrey.konovalov 2022-01-24 18:02 ` andrey.konovalov 2022-01-24 18:02 ` [PATCH v6 13/39] kasan, page_alloc: move kernel_init_free_pages " andrey.konovalov 2022-01-24 18:02 ` andrey.konovalov 2022-01-24 18:02 ` [PATCH v6 14/39] kasan, page_alloc: rework kasan_unpoison_pages call site andrey.konovalov 2022-01-24 18:02 ` andrey.konovalov 2022-01-24 18:02 ` [PATCH v6 15/39] kasan: clean up metadata byte definitions andrey.konovalov 2022-01-24 18:02 ` andrey.konovalov 2022-01-24 18:02 ` [PATCH v6 16/39] kasan: define KASAN_VMALLOC_INVALID for SW_TAGS andrey.konovalov 2022-01-24 18:02 ` andrey.konovalov 2022-01-24 18:04 ` [PATCH v6 17/39] kasan, x86, arm64, s390: rename functions for modules shadow andrey.konovalov 2022-01-24 18:04 ` andrey.konovalov 2022-01-24 18:04 ` [PATCH v6 18/39] kasan, vmalloc: drop outdated VM_KASAN comment andrey.konovalov 2022-01-24 18:04 ` andrey.konovalov 2022-01-24 18:04 ` [PATCH v6 19/39] kasan: reorder vmalloc hooks andrey.konovalov 2022-01-24 18:04 ` andrey.konovalov 2022-01-24 18:04 ` [PATCH v6 20/39] kasan: add wrappers for " andrey.konovalov 2022-01-24 18:04 ` andrey.konovalov 2022-01-24 18:04 ` [PATCH v6 21/39] kasan, vmalloc: reset tags in vmalloc functions andrey.konovalov 2022-01-24 18:04 ` andrey.konovalov 2022-01-24 18:04 ` [PATCH v6 22/39] kasan, fork: reset pointer tags of vmapped stacks andrey.konovalov 2022-01-24 18:04 ` andrey.konovalov 2022-01-24 18:04 ` [PATCH v6 23/39] kasan, arm64: " andrey.konovalov 2022-01-24 18:04 ` andrey.konovalov 2022-01-24 18:04 ` [PATCH v6 24/39] kasan, vmalloc: add vmalloc tagging for SW_TAGS andrey.konovalov 2022-01-24 18:04 ` andrey.konovalov 2022-01-24 18:04 ` [PATCH v6 25/39] kasan, vmalloc, arm64: mark vmalloc mappings as pgprot_tagged andrey.konovalov 2022-01-24 18:04 ` andrey.konovalov 2022-01-24 18:05 ` [PATCH v6 26/39] kasan, vmalloc: unpoison VM_ALLOC pages after mapping andrey.konovalov 2022-01-24 18:05 ` andrey.konovalov 2022-01-24 18:05 ` [PATCH v6 27/39] kasan, mm: only define ___GFP_SKIP_KASAN_POISON with HW_TAGS andrey.konovalov 2022-01-24 18:05 ` andrey.konovalov 2022-03-23 11:48 ` Vlastimil Babka 2022-03-23 11:48 ` Vlastimil Babka 2022-03-23 13:02 ` Sebastian Andrzej Siewior 2022-03-23 13:02 ` Sebastian Andrzej Siewior 2022-03-23 13:19 ` Vlastimil Babka 2022-03-23 13:19 ` Vlastimil Babka 2022-03-23 13:36 ` Andrey Konovalov 2022-03-23 13:36 ` Andrey Konovalov 2022-03-23 13:57 ` Vlastimil Babka 2022-03-23 13:57 ` Vlastimil Babka 2022-03-23 15:11 ` Matthew Wilcox 2022-03-23 15:11 ` Matthew Wilcox 2022-03-25 21:13 ` Andrew Morton 2022-03-25 21:13 ` Andrew Morton 2022-01-24 18:05 ` [PATCH v6 28/39] kasan, page_alloc: allow skipping unpoisoning for HW_TAGS andrey.konovalov 2022-01-24 18:05 ` andrey.konovalov 2022-01-24 18:05 ` [PATCH v6 29/39] kasan, page_alloc: allow skipping memory init " andrey.konovalov 2022-01-24 18:05 ` andrey.konovalov 2022-01-24 18:05 ` [PATCH v6 30/39] kasan, vmalloc: add vmalloc tagging " andrey.konovalov 2022-01-24 18:05 ` andrey.konovalov 2022-01-25 3:17 ` kernel test robot 2022-01-24 18:05 ` [PATCH v6 31/39] kasan, vmalloc: only tag normal vmalloc allocations andrey.konovalov 2022-01-24 18:05 ` andrey.konovalov 2022-01-25 4:19 ` kernel test robot 2022-01-25 7:56 ` kernel test robot 2022-03-08 15:17 ` Vasily Gorbik 2022-03-08 15:17 ` Vasily Gorbik 2022-03-08 15:30 ` Andrey Konovalov 2022-03-08 15:30 ` Andrey Konovalov 2022-03-08 15:48 ` Vasily Gorbik 2022-03-08 15:48 ` Vasily Gorbik 2022-01-24 18:05 ` [PATCH v6 32/39] kasan, arm64: don't tag executable " andrey.konovalov 2022-01-24 18:05 ` andrey.konovalov 2022-01-24 18:05 ` [PATCH v6 33/39] kasan: mark kasan_arg_stacktrace as __initdata andrey.konovalov 2022-01-24 18:05 ` andrey.konovalov 2022-01-24 18:05 ` [PATCH v6 34/39] kasan: clean up feature flags for HW_TAGS mode andrey.konovalov 2022-01-24 18:05 ` andrey.konovalov 2022-01-24 18:05 ` [PATCH v6 35/39] kasan: add kasan.vmalloc command line flag andrey.konovalov 2022-01-24 18:05 ` andrey.konovalov 2022-01-24 18:05 ` [PATCH v6 36/39] kasan: allow enabling KASAN_VMALLOC and SW/HW_TAGS andrey.konovalov 2022-01-24 18:05 ` andrey.konovalov 2022-01-24 18:05 ` [PATCH v6 37/39] arm64: select KASAN_VMALLOC for SW/HW_TAGS modes andrey.konovalov 2022-01-24 18:05 ` andrey.konovalov 2022-01-24 18:05 ` [PATCH v6 38/39] kasan: documentation updates andrey.konovalov 2022-01-24 18:05 ` andrey.konovalov 2022-01-24 18:05 ` [PATCH v6 39/39] kasan: improve vmalloc tests andrey.konovalov 2022-01-24 18:05 ` andrey.konovalov 2022-01-24 18:09 ` [PATCH v6 00/39] kasan, vmalloc, arm64: add vmalloc tagging support for SW/HW_TAGS Marco Elver 2022-01-24 18:09 ` Marco Elver 2022-01-24 18:32 ` Andrey Konovalov 2022-01-24 18:32 ` Andrey Konovalov 2022-04-28 14:13 ` Qian Cai 2022-04-28 14:13 ` Qian Cai 2022-04-28 15:28 ` Andrey Konovalov 2022-04-28 15:28 ` Andrey Konovalov 2022-04-28 16:12 ` Qian Cai 2022-04-28 16:12 ` Qian Cai
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