From 6bce244390a8bad89536ae0ea5c03c59ae155a12 Mon Sep 17 00:00:00 2001
From: Mel Gorman <mgorman@techsingularity.net>
Date: Mon, 5 Jul 2021 10:51:17 +0100
Subject: [PATCH] mm/page_alloc: Revert pahole zero-sized workaround
Commit dbbee9d5cd83 ("mm/page_alloc: convert per-cpu list protection to
local_lock") folded in a workaround patch for pahole that was unable to
deal with zero-sized percpu structures.
A superior workaround is achieved with commit a0b8200d06ad ("kbuild:
skip per-CPU BTF generation for pahole v1.18-v1.21").
This patch reverts the dummy field and the pahole version check.
Fixes: dbbee9d5cd83 ("mm/page_alloc: convert per-cpu list protection to local_lock")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
lib/Kconfig.debug | 3 ---
mm/page_alloc.c | 11 -----------
2 files changed, 14 deletions(-)
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 83a931c972f5e..831212722924c 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -324,9 +324,6 @@ config DEBUG_INFO_BTF
config PAHOLE_HAS_SPLIT_BTF
def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "119")
-config PAHOLE_HAS_ZEROSIZE_PERCPU_SUPPORT
- def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "122")
-
config DEBUG_INFO_BTF_MODULES
def_bool y
depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d6e94cc8066c1..3b97e17806be7 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -124,17 +124,6 @@ static DEFINE_MUTEX(pcp_batch_high_lock);
struct pagesets {
local_lock_t lock;
-#if defined(CONFIG_DEBUG_INFO_BTF) && \
- !defined(CONFIG_DEBUG_LOCK_ALLOC) && \
- !defined(CONFIG_PAHOLE_HAS_ZEROSIZE_PERCPU_SUPPORT)
- /*
- * pahole 1.21 and earlier gets confused by zero-sized per-CPU
- * variables and produces invalid BTF. Ensure that
- * sizeof(struct pagesets) != 0 for older versions of pahole.
- */
- char __pahole_hack;
- #warning "pahole too old to support zero-sized struct pagesets"
-#endif
};
static DEFINE_PER_CPU(struct pagesets, pagesets) = {
.lock = INIT_LOCAL_LOCK(lock),
--
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