The patch titled
Subject: mm/page_alloc: Revert pahole zero-sized workaround
has been added to the -mm tree. Its filename is
mm-page_alloc-revert-pahole-zero-sized-workaround.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-revert-pahole-zero-sized-workaround.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-revert-pahole-zero-sized-workaround.patch
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------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Subject: 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.
Link: https://lkml.kernel.org/r/20210705095117.GM3840@xxxxxxxxxxxxxxxxxxx
Fixes: dbbee9d5cd83 ("mm/page_alloc: convert per-cpu list protection to local_lock")
Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Cc: Chuck Lever III <chuck.lever@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/Kconfig.debug | 3 ---
mm/page_alloc.c | 11 -----------
2 files changed, 14 deletions(-)
--- a/lib/Kconfig.debug~mm-page_alloc-revert-pahole-zero-sized-workaround
+++ a/lib/Kconfig.debug
@@ -313,9 +313,6 @@ 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
--- a/mm/page_alloc.c~mm-page_alloc-revert-pahole-zero-sized-workaround
+++ a/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),
_
Patches currently in -mm which might be from mgorman@xxxxxxxxxxxxxxxxxxx are
mm-page_alloc-revert-pahole-zero-sized-workaround.patch
