* [PATCH v2 1/2] mm/zswap: add a flag to indicate if zpool can do sleep map
2021-02-13 7:58 [PATCH v2 0/2] Fix the compatibility of zsmalloc and zswap Barry Song
@ 2021-02-13 7:58 ` Barry Song
2021-02-13 7:58 ` [PATCH v2 2/2] mm: set the sleep_mapped to true for zbud and z3fold Barry Song
2021-02-13 22:33 ` [PATCH v2 0/2] Fix the compatibility of zsmalloc and zswap Andrew Morton
2 siblings, 0 replies; 4+ messages in thread
From: Barry Song @ 2021-02-13 7:58 UTC (permalink / raw)
To: akpm
Cc: linux-mm, Tian Tao, Nathan Chancellor, Colin Ian King,
Vitaly Wool, Sebastian Andrzej Siewior, Mike Galbraith,
Dan Streetman, Seth Jennings, Dan Carpenter, Barry Song
From: Tian Tao <tiantao6@hisilicon.com>
Patch series "Fix the compatibility of zsmalloc and zswap".
The compatibility of zsmalloc and zswap was broken by commit 1ec3b5fe6eec
("mm/zswap: move to use crypto_acomp API for hardware acceleration").
Patch #1 adds a flag to zpool, then zswap used it to determine if zpool
drivers such as zbud/z3fold/zsmalloc will enter an atomic context after
mapping.
The difference between zbud/z3fold and zsmalloc is that zsmalloc requires
an atomic context that since its map function holds a preempt-disabled
lock, but zbud/z3fold don't require an atomic context. So patch #2 sets
flag sleep_mapped to true indicating that zbud/z3fold can sleep after
mapping. zsmalloc didn't support sleep after mapping, so don't set that
flag to true.
This patch (of 2):
Add a flag to zpool, named as "sleep_mapped", and have it set true for
zbud/z3fold, not set this flag for zsmalloc, so its default value is
false. Then zswap could go the current path if the flag is true; and if
it's false, copy data from src to a temporary buffer, then unmap the
handle, take the mutex, process the buffer instead of src to avoid
sleeping function called from atomic context.
[natechancellor@gmail.com: add return value in zswap_frontswap_load]
Link: https://lkml.kernel.org/r/20210121214804.926843-1-natechancellor@gmail.com
[tiantao6@hisilicon.com: fix potential memory leak]
Link: https://lkml.kernel.org/r/1611538365-51811-1-git-send-email-tiantao6@hisilicon.com
[colin.king@canonical.com: fix potential uninitialized pointer read on tmp]
Link: https://lkml.kernel.org/r/20210128141728.639030-1-colin.king@canonical.com
[tiantao6@hisilicon.com: fix variable 'entry' is uninitialized when used]
Link: https://lkml.kernel.org/r/1611223030-58346-1-git-send-email-tiantao6@hisilicon.com
Link: https://lkml.kernel.org/r/1611035683-12732-1-git-send-email-tiantao6@hisilicon.com
Link: https://lkml.kernel.org/r/1611035683-12732-2-git-send-email-tiantao6@hisilicon.com
[song.bao.hua@hisilicon.com: Rewrote changelog]
Fixes: 1ec3b5fe6e ("mm/zswap: move to use crypto_acomp API for hardware acceleration")
Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reported-by: Mike Galbraith <efault@gmx.de>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
---
-v2:
* folded-merged sanitizer check patches into this one(done by Andrew);
* added fixes tag in changelog and refined commit log(done by Barry)
include/linux/zpool.h | 3 +++
mm/zpool.c | 13 +++++++++++
mm/zswap.c | 51 ++++++++++++++++++++++++++++++++++++++-----
3 files changed, 62 insertions(+), 5 deletions(-)
diff --git a/include/linux/zpool.h b/include/linux/zpool.h
index 51bf43076165..e8997010612a 100644
--- a/include/linux/zpool.h
+++ b/include/linux/zpool.h
@@ -73,6 +73,7 @@ u64 zpool_get_total_size(struct zpool *pool);
* @malloc: allocate mem from a pool.
* @free: free mem from a pool.
* @shrink: shrink the pool.
+ * @sleep_mapped: whether zpool driver can sleep during map.
* @map: map a handle.
* @unmap: unmap a handle.
* @total_size: get total size of a pool.
@@ -100,6 +101,7 @@ struct zpool_driver {
int (*shrink)(void *pool, unsigned int pages,
unsigned int *reclaimed);
+ bool sleep_mapped;
void *(*map)(void *pool, unsigned long handle,
enum zpool_mapmode mm);
void (*unmap)(void *pool, unsigned long handle);
@@ -112,5 +114,6 @@ void zpool_register_driver(struct zpool_driver *driver);
int zpool_unregister_driver(struct zpool_driver *driver);
bool zpool_evictable(struct zpool *pool);
+bool zpool_can_sleep_mapped(struct zpool *pool);
#endif
diff --git a/mm/zpool.c b/mm/zpool.c
index 3744a2d1a624..5ed71207ced7 100644
--- a/mm/zpool.c
+++ b/mm/zpool.c
@@ -23,6 +23,7 @@ struct zpool {
void *pool;
const struct zpool_ops *ops;
bool evictable;
+ bool can_sleep_mapped;
struct list_head list;
};
@@ -183,6 +184,7 @@ struct zpool *zpool_create_pool(const char *type, const char *name, gfp_t gfp,
zpool->pool = driver->create(name, gfp, ops, zpool);
zpool->ops = ops;
zpool->evictable = driver->shrink && ops && ops->evict;
+ zpool->can_sleep_mapped = driver->sleep_mapped;
if (!zpool->pool) {
pr_err("couldn't create %s pool\n", type);
@@ -393,6 +395,17 @@ bool zpool_evictable(struct zpool *zpool)
return zpool->evictable;
}
+/**
+ * zpool_can_sleep_mapped - Test if zpool can sleep when do mapped.
+ * @zpool: The zpool to test
+ *
+ * Returns: true if zpool can sleep; false otherwise.
+ */
+bool zpool_can_sleep_mapped(struct zpool *zpool)
+{
+ return zpool->can_sleep_mapped;
+}
+
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>");
MODULE_DESCRIPTION("Common API for compressed memory storage");
diff --git a/mm/zswap.c b/mm/zswap.c
index 182f6ad5aa69..1566cc3ab7f4 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -935,13 +935,19 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
struct scatterlist input, output;
struct crypto_acomp_ctx *acomp_ctx;
- u8 *src;
+ u8 *src, *tmp = NULL;
unsigned int dlen;
int ret;
struct writeback_control wbc = {
.sync_mode = WB_SYNC_NONE,
};
+ if (!zpool_can_sleep_mapped(pool)) {
+ tmp = kmalloc(PAGE_SIZE, GFP_ATOMIC);
+ if (!tmp)
+ return -ENOMEM;
+ }
+
/* extract swpentry from data */
zhdr = zpool_map_handle(pool, handle, ZPOOL_MM_RO);
swpentry = zhdr->swpentry; /* here */
@@ -955,6 +961,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
/* entry was invalidated */
spin_unlock(&tree->lock);
zpool_unmap_handle(pool, handle);
+ kfree(tmp);
return 0;
}
spin_unlock(&tree->lock);
@@ -979,6 +986,14 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
dlen = PAGE_SIZE;
src = (u8 *)zhdr + sizeof(struct zswap_header);
+ if (!zpool_can_sleep_mapped(pool)) {
+
+ memcpy(tmp, src, entry->length);
+ src = tmp;
+
+ zpool_unmap_handle(pool, handle);
+ }
+
mutex_lock(acomp_ctx->mutex);
sg_init_one(&input, src, entry->length);
sg_init_table(&output, 1);
@@ -1033,7 +1048,11 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
spin_unlock(&tree->lock);
end:
- zpool_unmap_handle(pool, handle);
+ if (zpool_can_sleep_mapped(pool))
+ zpool_unmap_handle(pool, handle);
+ else
+ kfree(tmp);
+
return ret;
}
@@ -1235,7 +1254,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
struct zswap_entry *entry;
struct scatterlist input, output;
struct crypto_acomp_ctx *acomp_ctx;
- u8 *src, *dst;
+ u8 *src, *dst, *tmp;
unsigned int dlen;
int ret;
@@ -1253,15 +1272,33 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
dst = kmap_atomic(page);
zswap_fill_page(dst, entry->value);
kunmap_atomic(dst);
+ ret = 0;
goto freeentry;
}
+ if (!zpool_can_sleep_mapped(entry->pool->zpool)) {
+
+ tmp = kmalloc(entry->length, GFP_ATOMIC);
+ if (!tmp) {
+ ret = -ENOMEM;
+ goto freeentry;
+ }
+ }
+
/* decompress */
dlen = PAGE_SIZE;
src = zpool_map_handle(entry->pool->zpool, entry->handle, ZPOOL_MM_RO);
if (zpool_evictable(entry->pool->zpool))
src += sizeof(struct zswap_header);
+ if (!zpool_can_sleep_mapped(entry->pool->zpool)) {
+
+ memcpy(tmp, src, entry->length);
+ src = tmp;
+
+ zpool_unmap_handle(entry->pool->zpool, entry->handle);
+ }
+
acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx);
mutex_lock(acomp_ctx->mutex);
sg_init_one(&input, src, entry->length);
@@ -1271,7 +1308,11 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
ret = crypto_wait_req(crypto_acomp_decompress(acomp_ctx->req), &acomp_ctx->wait);
mutex_unlock(acomp_ctx->mutex);
- zpool_unmap_handle(entry->pool->zpool, entry->handle);
+ if (zpool_can_sleep_mapped(entry->pool->zpool))
+ zpool_unmap_handle(entry->pool->zpool, entry->handle);
+ else
+ kfree(tmp);
+
BUG_ON(ret);
freeentry:
@@ -1279,7 +1320,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
zswap_entry_put(tree, entry);
spin_unlock(&tree->lock);
- return 0;
+ return ret;
}
/* frees an entry in zswap */
--
2.25.1
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH v2 2/2] mm: set the sleep_mapped to true for zbud and z3fold
2021-02-13 7:58 [PATCH v2 0/2] Fix the compatibility of zsmalloc and zswap Barry Song
2021-02-13 7:58 ` [PATCH v2 1/2] mm/zswap: add a flag to indicate if zpool can do sleep map Barry Song
@ 2021-02-13 7:58 ` Barry Song
2021-02-13 22:33 ` [PATCH v2 0/2] Fix the compatibility of zsmalloc and zswap Andrew Morton
2 siblings, 0 replies; 4+ messages in thread
From: Barry Song @ 2021-02-13 7:58 UTC (permalink / raw)
To: akpm
Cc: linux-mm, Tian Tao, Vitaly Wool, Sebastian Andrzej Siewior,
Mike Galbraith, Seth Jennings, Dan Streetman, Barry Song
From: Tian Tao <tiantao6@hisilicon.com>
zpool driver adds a flag to indicate whether the zpool driver can enter
an atomic context after mapping. This patch sets it true for z3fold and
zbud.
Link: https://lkml.kernel.org/r/1611035683-12732-3-git-send-email-tiantao6@hisilicon.com
[song.bao.hua@hisilicon.com: Rewrote changelog]
Fixes: 1ec3b5fe6e ("mm/zswap: move to use crypto_acomp API for hardware acceleration")
Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reported-by: Mike Galbraith <efault@gmx.de>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
---
-v2:
* added fixes tag in changelog and refined commit log(done by Barry)
mm/z3fold.c | 1 +
mm/zbud.c | 1 +
2 files changed, 2 insertions(+)
diff --git a/mm/z3fold.c b/mm/z3fold.c
index dacb0d70fa61..234b46f01e83 100644
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -1778,6 +1778,7 @@ static u64 z3fold_zpool_total_size(void *pool)
static struct zpool_driver z3fold_zpool_driver = {
.type = "z3fold",
+ .sleep_mapped = true,
.owner = THIS_MODULE,
.create = z3fold_zpool_create,
.destroy = z3fold_zpool_destroy,
diff --git a/mm/zbud.c b/mm/zbud.c
index c49966ece674..7ec5f27a68b0 100644
--- a/mm/zbud.c
+++ b/mm/zbud.c
@@ -203,6 +203,7 @@ static u64 zbud_zpool_total_size(void *pool)
static struct zpool_driver zbud_zpool_driver = {
.type = "zbud",
+ .sleep_mapped = true,
.owner = THIS_MODULE,
.create = zbud_zpool_create,
.destroy = zbud_zpool_destroy,
--
2.25.1
^ permalink raw reply [flat|nested] 4+ messages in thread