percpu: make pcpu_nr_empty_pop_pages per chunk type
nr_empty_pop_pages is used to guarantee that there are some free
populated pages to satisfy atomic allocations. Accounted and
non-accounted allocations are using separate sets of chunks,
so both need to have a surplus of empty pages.
This commit makes pcpu_nr_empty_pop_pages and the corresponding logic
per chunk type.
[Dennis]
This issue came up as I was reviewing [1] and realized I missed this.
Simultaneously, it was reported btrfs was seeing failed atomic
allocations in fsstress tests [2] and [3].
[1] https://lore.kernel.org/linux-mm/20210324190626.564297-1-guro@fb.com/
[2] https://lore.kernel.org/linux-mm/20210401185158.3275.409509F4@e16-tech.com/
[3] https://lore.kernel.org/linux-mm/CAL3q7H5RNBjCi708GH7jnczAOe0BLnacT9C+OBgA-Dx9jhB6SQ@mail.gmail.com/
Fixes: 3c7be18ac9a0 ("mm: memcg/percpu: account percpu memory to memory cgroups")
Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Roman Gushchin <guro@fb.com>
Tested-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
diff --git a/mm/percpu-stats.c b/mm/percpu-stats.c
index c8400a2..f6026db 100644
--- a/mm/percpu-stats.c
+++ b/mm/percpu-stats.c
@@ -145,6 +145,7 @@ static int percpu_stats_show(struct seq_file *m, void *v)
int slot, max_nr_alloc;
int *buffer;
enum pcpu_chunk_type type;
+ int nr_empty_pop_pages;
alloc_buffer:
spin_lock_irq(&pcpu_lock);
@@ -165,7 +166,11 @@ static int percpu_stats_show(struct seq_file *m, void *v)
goto alloc_buffer;
}
-#define PL(X) \
+ nr_empty_pop_pages = 0;
+ for (type = 0; type < PCPU_NR_CHUNK_TYPES; type++)
+ nr_empty_pop_pages += pcpu_nr_empty_pop_pages[type];
+
+#define PL(X) \
seq_printf(m, " %-20s: %12lld\n", #X, (long long int)pcpu_stats_ai.X)
seq_printf(m,
@@ -196,7 +201,7 @@ static int percpu_stats_show(struct seq_file *m, void *v)
PU(nr_max_chunks);
PU(min_alloc_size);
PU(max_alloc_size);
- P("empty_pop_pages", pcpu_nr_empty_pop_pages);
+ P("empty_pop_pages", nr_empty_pop_pages);
seq_putc(m, '\n');
#undef PU
