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AJvYcCXEszROhPGrz8M5u8c6Ps99jmWbYApqEE1HJvXnXv6FP+aFkOHX2GpT6A4gI+5wfPn6BjTNioEX/reidcw=@vger.kernel.org X-Gm-Message-State: AOJu0YxxUKfoUiDIOfp7GXTJPqecuOMMbhZLwyrueTkezaNL0qwfFSuA 0cD1hz8lXQfrVxsmXVudjw770KpKIhJKgxzpK7aEw/2vbkESOtdThVjcKQEQpuOC090k4stJ0oI ZNBm+15ciq+752g== X-Received: from wmma2.prod.google.com ([2002:a05:600c:2242:b0:486:fdc0:fa81]) (user=jackmanb job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:4a13:b0:487:1e7:8e7 with SMTP id 5b1f17b1804b1-48701e70a2fmr20888135e9.33.1774031044829; Fri, 20 Mar 2026 11:24:04 -0700 (PDT) Date: Fri, 20 Mar 2026 18:23:41 +0000 In-Reply-To: <20260320-page_alloc-unmapped-v2-0-28bf1bd54f41@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260320-page_alloc-unmapped-v2-0-28bf1bd54f41@google.com> X-Mailer: b4 0.14.3 Message-ID: <20260320-page_alloc-unmapped-v2-17-28bf1bd54f41@google.com> Subject: [PATCH v2 17/22] mm/page_alloc: rename ALLOC_NON_BLOCK back to _HARDER From: Brendan Jackman To: Borislav Petkov , Dave Hansen , Peter Zijlstra , Andrew Morton , David Hildenbrand , Vlastimil Babka , Wei Xu , Johannes Weiner , Zi Yan , Lorenzo Stoakes Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, x86@kernel.org, rppt@kernel.org, Sumit Garg , derkling@google.com, reijiw@google.com, Will Deacon , rientjes@google.com, "Kalyazin, Nikita" , patrick.roy@linux.dev, "Itazuri, Takahiro" , Andy Lutomirski , David Kaplan , Thomas Gleixner , Brendan Jackman , Yosry Ahmed Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Commit 1ebbb21811b7 ("mm/page_alloc: explicitly define how __GFP_HIGH non-blocking allocations accesses reserves") renamed ALLOC_HARDER to ALLOC_NON_BLOCK because the former is "a vague description". However, vagueness is accurate here, this is a vague flag. It is not set for __GFP_NOMEMALLOC. It doesn't really mean "allocate without blocking" but rather "allow dipping into atomic reserves, _because_ of the need not to block". A later commit will need an alloc flag that really means "don't block here", so go back to the flag's old name and update the commentary to try and give it a slightly clearer meaning. Signed-off-by: Brendan Jackman --- mm/internal.h | 9 +++++---- mm/page_alloc.c | 8 ++++---- 2 files changed, 9 insertions(+), 8 deletions(-) diff --git a/mm/internal.h b/mm/internal.h index d929274d73b92..cc19a90a7933f 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1413,9 +1413,10 @@ unsigned int reclaim_clean_pages_from_list(struct zo= ne *zone, #define ALLOC_OOM ALLOC_NO_WATERMARKS #endif =20 -#define ALLOC_NON_BLOCK 0x10 /* Caller cannot block. Allow access - * to 25% of the min watermark or - * 62.5% if __GFP_HIGH is set. +#define ALLOC_HARDER 0x10 /* Because the caller cannot block, + * allow access * to 25% of the min + * watermark or 62.5% if __GFP_HIGH is + * set. */ #define ALLOC_MIN_RESERVE 0x20 /* __GFP_HIGH set. Allow access to 50% * of the min watermark. @@ -1432,7 +1433,7 @@ unsigned int reclaim_clean_pages_from_list(struct zon= e *zone, #define ALLOC_KSWAPD 0x800 /* allow waking of kswapd, __GFP_KSWAPD_RECLAI= M set */ =20 /* Flags that allow allocations below the min watermark. */ -#define ALLOC_RESERVES (ALLOC_NON_BLOCK|ALLOC_MIN_RESERVE|ALLOC_HIGHATOMIC= |ALLOC_OOM) +#define ALLOC_RESERVES (ALLOC_HARDER|ALLOC_MIN_RESERVE|ALLOC_HIGHATOMIC|AL= LOC_OOM) =20 enum ttu_flags; struct tlbflush_unmap_batch; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 53848312a0c21..9a07c552a1f8a 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3355,7 +3355,7 @@ struct page *rmqueue_buddy(struct zone *preferred_zon= e, struct zone *zone, * reserves as failing now is worse than failing a * high-order atomic allocation in the future. */ - if (!page && (alloc_flags & (ALLOC_OOM|ALLOC_NON_BLOCK))) + if (!page && (alloc_flags & (ALLOC_OOM|ALLOC_HARDER))) page =3D __rmqueue_smallest(zone, order, ft_high); =20 if (!page) { @@ -3717,7 +3717,7 @@ bool __zone_watermark_ok(struct zone *z, unsigned int= order, unsigned long mark, * or (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) do not get * access to the min reserve. */ - if (alloc_flags & ALLOC_NON_BLOCK) + if (alloc_flags & ALLOC_HARDER) min -=3D min / 4; } =20 @@ -4602,7 +4602,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask, unsigned int order) * The caller may dip into page reserves a bit more if the caller * cannot run direct reclaim, or if the caller has realtime scheduling * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will - * set both ALLOC_NON_BLOCK and ALLOC_MIN_RESERVE(__GFP_HIGH). + * set both ALLOC_HARDER and ALLOC_MIN_RESERVE(__GFP_HIGH). */ alloc_flags |=3D (__force int) (gfp_mask & (__GFP_HIGH | __GFP_KSWAPD_RECLAIM)); @@ -4613,7 +4613,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask, unsigned int order) * if it can't schedule. */ if (!(gfp_mask & __GFP_NOMEMALLOC)) { - alloc_flags |=3D ALLOC_NON_BLOCK; + alloc_flags |=3D ALLOC_HARDER; =20 if (order > 0 && (alloc_flags & ALLOC_MIN_RESERVE)) alloc_flags |=3D ALLOC_HIGHATOMIC; --=20 2.51.2