Commit 6bce2443 authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
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mm/page_alloc: Revert pahole zero-sized workaround 



Commit dbbee9d5 ("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 a0b8200d ("kbuild:
skip per-CPU BTF generation for pahole v1.18-v1.21").

This patch reverts the dummy field and the pahole version check.

Fixes: dbbee9d5 ("mm/page_alloc: convert per-cpu list protection to local_lock")
Signed-off-by: default avatarMel Gorman <mgorman@techsingularity.net>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1e16624d

lib/Kconfig.debug

+0 −3
Original line number Diff line number Diff line
@@ -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

mm/page_alloc.c

+0 −11
Original line number Diff line number Diff line
@@ -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),