The patch titled
Subject: block/partitions: optimize memory allocation in check_partition()
has been added to the -mm tree. Its filename is
block-partitions-optimize-memory-allocation-in-check_partition.patch
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------------------------------------------------------
From: Ming Lei <ming.lei@xxxxxxxxxxxxx>
Subject: block/partitions: optimize memory allocation in check_partition()
Currently, sizeof(struct parsed_partitions) may be 64KB in 32bit arch, so
it is easy to trigger page allocation failure by check_partition,
especially in hotplug block device situation(such as, USB mass storage,
MMC card, ...), and Felipe Balbi has observed the failure.
This patch does below optimizations on the allocation of struct
parsed_partitions to try to address the issue:
- make parsed_partitions.parts as pointer so that the pointed memory can
fit in 32KB buffer, then approximate 32KB memory can be saved
- vmalloc the buffer pointed by parsed_partitions.parts because 32KB is
still a bit big for kmalloc
- given that many devices have the partition count limit, so only
allocate disk_max_parts() partitions instead of 256 partitions always
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxxxxx>
Reported-by: Felipe Balbi <balbi@xxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
block/partition-generic.c | 4 +--
block/partitions/check.c | 37 +++++++++++++++++++++++++++++++-----
block/partitions/check.h | 4 ++-
3 files changed, 37 insertions(+), 8 deletions(-)
diff -puN block/partition-generic.c~block-partition-optimize-memory-allocation-in-check_partition block/partition-generic.c
--- a/block/partition-generic.c~block-partition-optimize-memory-allocation-in-check_partition
+++ a/block/partition-generic.c
@@ -418,7 +418,7 @@ int rescan_partitions(struct gendisk *di
int p, highest, res;
rescan:
if (state && !IS_ERR(state)) {
- kfree(state);
+ free_partitions(state);
state = NULL;
}
@@ -525,7 +525,7 @@ rescan:
md_autodetect_dev(part_to_dev(part)->devt);
#endif
}
- kfree(state);
+ free_partitions(state);
return 0;
}
diff -puN block/partitions/check.c~block-partition-optimize-memory-allocation-in-check_partition block/partitions/check.c
--- a/block/partitions/check.c~block-partition-optimize-memory-allocation-in-check_partition
+++ a/block/partitions/check.c
@@ -14,6 +14,7 @@
*/
#include <linux/slab.h>
+#include <linux/vmalloc.h>
#include <linux/ctype.h>
#include <linux/genhd.h>
@@ -106,18 +107,45 @@ static int (*check_part[])(struct parsed
NULL
};
+static struct parsed_partitions *allocate_partitions(struct gendisk *hd)
+{
+ struct parsed_partitions *state;
+ int nr;
+
+ state = kzalloc(sizeof(*state), GFP_KERNEL);
+ if (!state)
+ return NULL;
+
+ nr = disk_max_parts(hd);
+ state->parts = vzalloc(nr * sizeof(state->parts[0]));
+ if (!state->parts) {
+ kfree(state);
+ return NULL;
+ }
+
+ state->limit = nr;
+
+ return state;
+}
+
+void free_partitions(struct parsed_partitions *state)
+{
+ vfree(state->parts);
+ kfree(state);
+}
+
struct parsed_partitions *
check_partition(struct gendisk *hd, struct block_device *bdev)
{
struct parsed_partitions *state;
int i, res, err;
- state = kzalloc(sizeof(struct parsed_partitions), GFP_KERNEL);
+ state = allocate_partitions(hd);
if (!state)
return NULL;
state->pp_buf = (char *)__get_free_page(GFP_KERNEL);
if (!state->pp_buf) {
- kfree(state);
+ free_partitions(state);
return NULL;
}
state->pp_buf[0] = '\0';
@@ -128,10 +156,9 @@ check_partition(struct gendisk *hd, stru
if (isdigit(state->name[strlen(state->name)-1]))
sprintf(state->name, "p");
- state->limit = disk_max_parts(hd);
i = res = err = 0;
while (!res && check_part[i]) {
- memset(&state->parts, 0, sizeof(state->parts));
+ memset(state->parts, 0, state->limit * sizeof(state->parts[0]));
res = check_part[i++](state);
if (res < 0) {
/* We have hit an I/O error which we don't report now.
@@ -161,6 +188,6 @@ check_partition(struct gendisk *hd, stru
printk(KERN_INFO "%s", state->pp_buf);
free_page((unsigned long)state->pp_buf);
- kfree(state);
+ free_partitions(state);
return ERR_PTR(res);
}
diff -puN block/partitions/check.h~block-partition-optimize-memory-allocation-in-check_partition block/partitions/check.h
--- a/block/partitions/check.h~block-partition-optimize-memory-allocation-in-check_partition
+++ a/block/partitions/check.h
@@ -15,13 +15,15 @@ struct parsed_partitions {
int flags;
bool has_info;
struct partition_meta_info info;
- } parts[DISK_MAX_PARTS];
+ } *parts;
int next;
int limit;
bool access_beyond_eod;
char *pp_buf;
};
+void free_partitions(struct parsed_partitions *state);
+
struct parsed_partitions *
check_partition(struct gendisk *, struct block_device *);
_
Patches currently in -mm which might be from ming.lei@xxxxxxxxxxxxx are
origin.patch
linux-next.patch
mm-teach-mm-by-current-context-info-to-not-do-i-o-during-memory-allocation.patch
pm-runtime-introduce-pm_runtime_set_memalloc_noio.patch
block-genhdc-apply-pm_runtime_set_memalloc_noio-on-block-devices.patch
net-core-apply-pm_runtime_set_memalloc_noio-on-network-devices.patch
pm-runtime-force-memory-allocation-with-no-i-o-during-runtime-pm-callbcack.patch
usb-forbid-memory-allocation-with-i-o-during-bus-reset.patch
block-partitions-mac-obey-the-state-limit-constraint.patch
block-partitions-optimize-memory-allocation-in-check_partition.patch
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