mm/page_alloc: Revert pahole zero-sized workaround

Commit 17e158402c6a ("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 f192e44fcf2a ("kbuild:
skip per-CPU BTF generation for pahole v1.18-v1.21").

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

Fixes: 17e158402c6a ("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>

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 83a931c972f5e74fe93306bbec1e649e1493f915..831212722924c7b6e3b4d291d94207f54ba58ac9 100644 (file)
--- 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 d6e94cc8066c1f46c772e660695010ddce37f817..3b97e17806be7f83bc61e61487a8d41204547568 100644 (file)
--- 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),