From: Michal Hocko <[email protected]>
A support for GFP_NO{FS,IO} and __GFP_NOFAIL has been implemented
by previous patches so we can allow the support for kvmalloc. This
will allow some external users to simplify or completely remove
their helpers.
GFP_NOWAIT semantic hasn't been supported so far but it hasn't been
explicitly documented so let's add a note about that.
ceph_kvmalloc is the first helper to be dropped and changed to
kvmalloc.
Signed-off-by: Michal Hocko <[email protected]>
---
include/linux/ceph/libceph.h | 1 -
mm/util.c | 15 ++++-----------
net/ceph/buffer.c | 4 ++--
net/ceph/ceph_common.c | 27 ---------------------------
net/ceph/crypto.c | 2 +-
net/ceph/messenger.c | 2 +-
net/ceph/messenger_v2.c | 2 +-
net/ceph/osdmap.c | 12 ++++++------
8 files changed, 15 insertions(+), 50 deletions(-)
diff --git a/include/linux/ceph/libceph.h b/include/linux/ceph/libceph.h
index 409d8c29bc4f..309acbcb5a8a 100644
--- a/include/linux/ceph/libceph.h
+++ b/include/linux/ceph/libceph.h
@@ -295,7 +295,6 @@ extern bool libceph_compatible(void *data);
extern const char *ceph_msg_type_name(int type);
extern int ceph_check_fsid(struct ceph_client *client, struct ceph_fsid *fsid);
-extern void *ceph_kvmalloc(size_t size, gfp_t flags);
struct fs_parameter;
struct fc_log;
diff --git a/mm/util.c b/mm/util.c
index bacabe446906..fdec6b4b1267 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -549,13 +549,10 @@ EXPORT_SYMBOL(vm_mmap);
* Uses kmalloc to get the memory but if the allocation fails then falls back
* to the vmalloc allocator. Use kvfree for freeing the memory.
*
- * Reclaim modifiers - __GFP_NORETRY and __GFP_NOFAIL are not supported.
+ * Reclaim modifiers - __GFP_NORETRY and GFP_NOWAIT are not supported.
* __GFP_RETRY_MAYFAIL is supported, and it should be used only if kmalloc is
* preferable to the vmalloc fallback, due to visible performance drawbacks.
*
- * Please note that any use of gfp flags outside of GFP_KERNEL is careful to not
- * fall back to vmalloc.
- *
* Return: pointer to the allocated memory of %NULL in case of failure
*/
void *kvmalloc_node(size_t size, gfp_t flags, int node)
@@ -563,13 +560,6 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node)
gfp_t kmalloc_flags = flags;
void *ret;
- /*
- * vmalloc uses GFP_KERNEL for some internal allocations (e.g page tables)
- * so the given set of flags has to be compatible.
- */
- if ((flags & GFP_KERNEL) != GFP_KERNEL)
- return kmalloc_node(size, flags, node);
-
/*
* We want to attempt a large physically contiguous block first because
* it is less likely to fragment multiple larger blocks and therefore
@@ -582,6 +572,9 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node)
if (!(kmalloc_flags & __GFP_RETRY_MAYFAIL))
kmalloc_flags |= __GFP_NORETRY;
+
+ /* nofail semantic is implemented by the vmalloc fallback */
+ kmalloc_flags &= ~__GFP_NOFAIL;
}
ret = kmalloc_node(size, kmalloc_flags, node);
diff --git a/net/ceph/buffer.c b/net/ceph/buffer.c
index 5622763ad402..7e51f128045d 100644
--- a/net/ceph/buffer.c
+++ b/net/ceph/buffer.c
@@ -7,7 +7,7 @@
#include <linux/ceph/buffer.h>
#include <linux/ceph/decode.h>
-#include <linux/ceph/libceph.h> /* for ceph_kvmalloc */
+#include <linux/ceph/libceph.h> /* for kvmalloc */
struct ceph_buffer *ceph_buffer_new(size_t len, gfp_t gfp)
{
@@ -17,7 +17,7 @@ struct ceph_buffer *ceph_buffer_new(size_t len, gfp_t gfp)
if (!b)
return NULL;
- b->vec.iov_base = ceph_kvmalloc(len, gfp);
+ b->vec.iov_base = kvmalloc(len, gfp);
if (!b->vec.iov_base) {
kfree(b);
return NULL;
diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c
index 97d6ea763e32..9441b4a4912b 100644
--- a/net/ceph/ceph_common.c
+++ b/net/ceph/ceph_common.c
@@ -190,33 +190,6 @@ int ceph_compare_options(struct ceph_options *new_opt,
}
EXPORT_SYMBOL(ceph_compare_options);
-/*
- * kvmalloc() doesn't fall back to the vmalloc allocator unless flags are
- * compatible with (a superset of) GFP_KERNEL. This is because while the
- * actual pages are allocated with the specified flags, the page table pages
- * are always allocated with GFP_KERNEL.
- *
- * ceph_kvmalloc() may be called with GFP_KERNEL, GFP_NOFS or GFP_NOIO.
- */
-void *ceph_kvmalloc(size_t size, gfp_t flags)
-{
- void *p;
-
- if ((flags & (__GFP_IO | __GFP_FS)) == (__GFP_IO | __GFP_FS)) {
- p = kvmalloc(size, flags);
- } else if ((flags & (__GFP_IO | __GFP_FS)) == __GFP_IO) {
- unsigned int nofs_flag = memalloc_nofs_save();
- p = kvmalloc(size, GFP_KERNEL);
- memalloc_nofs_restore(nofs_flag);
- } else {
- unsigned int noio_flag = memalloc_noio_save();
- p = kvmalloc(size, GFP_KERNEL);
- memalloc_noio_restore(noio_flag);
- }
-
- return p;
-}
-
static int parse_fsid(const char *str, struct ceph_fsid *fsid)
{
int i = 0;
diff --git a/net/ceph/crypto.c b/net/ceph/crypto.c
index 92d89b331645..051d22c0e4ad 100644
--- a/net/ceph/crypto.c
+++ b/net/ceph/crypto.c
@@ -147,7 +147,7 @@ void ceph_crypto_key_destroy(struct ceph_crypto_key *key)
static const u8 *aes_iv = (u8 *)CEPH_AES_IV;
/*
- * Should be used for buffers allocated with ceph_kvmalloc().
+ * Should be used for buffers allocated with kvmalloc().
* Currently these are encrypt out-buffer (ceph_buffer) and decrypt
* in-buffer (msg front).
*
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 57d043b382ed..7b891be799d2 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -1920,7 +1920,7 @@ struct ceph_msg *ceph_msg_new2(int type, int front_len, int max_data_items,
/* front */
if (front_len) {
- m->front.iov_base = ceph_kvmalloc(front_len, flags);
+ m->front.iov_base = kvmalloc(front_len, flags);
if (m->front.iov_base == NULL) {
dout("ceph_msg_new can't allocate %d bytes\n",
front_len);
diff --git a/net/ceph/messenger_v2.c b/net/ceph/messenger_v2.c
index cc40ce4e02fb..c4099b641b38 100644
--- a/net/ceph/messenger_v2.c
+++ b/net/ceph/messenger_v2.c
@@ -308,7 +308,7 @@ static void *alloc_conn_buf(struct ceph_connection *con, int len)
if (WARN_ON(con->v2.conn_buf_cnt >= ARRAY_SIZE(con->v2.conn_bufs)))
return NULL;
- buf = ceph_kvmalloc(len, GFP_NOIO);
+ buf = kvmalloc(len, GFP_NOIO);
if (!buf)
return NULL;
diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index 75b738083523..2823bb3cff55 100644
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -980,7 +980,7 @@ static struct crush_work *alloc_workspace(const struct crush_map *c)
work_size = crush_work_size(c, CEPH_PG_MAX_SIZE);
dout("%s work_size %zu bytes\n", __func__, work_size);
- work = ceph_kvmalloc(work_size, GFP_NOIO);
+ work = kvmalloc(work_size, GFP_NOIO);
if (!work)
return NULL;
@@ -1190,9 +1190,9 @@ static int osdmap_set_max_osd(struct ceph_osdmap *map, u32 max)
if (max == map->max_osd)
return 0;
- state = ceph_kvmalloc(array_size(max, sizeof(*state)), GFP_NOFS);
- weight = ceph_kvmalloc(array_size(max, sizeof(*weight)), GFP_NOFS);
- addr = ceph_kvmalloc(array_size(max, sizeof(*addr)), GFP_NOFS);
+ state = kvmalloc(array_size(max, sizeof(*state)), GFP_NOFS);
+ weight = kvmalloc(array_size(max, sizeof(*weight)), GFP_NOFS);
+ addr = kvmalloc(array_size(max, sizeof(*addr)), GFP_NOFS);
if (!state || !weight || !addr) {
kvfree(state);
kvfree(weight);
@@ -1222,7 +1222,7 @@ static int osdmap_set_max_osd(struct ceph_osdmap *map, u32 max)
if (map->osd_primary_affinity) {
u32 *affinity;
- affinity = ceph_kvmalloc(array_size(max, sizeof(*affinity)),
+ affinity = kvmalloc(array_size(max, sizeof(*affinity)),
GFP_NOFS);
if (!affinity)
return -ENOMEM;
@@ -1503,7 +1503,7 @@ static int set_primary_affinity(struct ceph_osdmap *map, int osd, u32 aff)
if (!map->osd_primary_affinity) {
int i;
- map->osd_primary_affinity = ceph_kvmalloc(
+ map->osd_primary_affinity = kvmalloc(
array_size(map->max_osd, sizeof(*map->osd_primary_affinity)),
GFP_NOFS);
if (!map->osd_primary_affinity)
--
2.30.2
On Tue, 26 Oct 2021, Michal Hocko wrote:
> From: Michal Hocko <[email protected]>
>
> A support for GFP_NO{FS,IO} and __GFP_NOFAIL has been implemented
> by previous patches so we can allow the support for kvmalloc. This
> will allow some external users to simplify or completely remove
> their helpers.
>
> GFP_NOWAIT semantic hasn't been supported so far but it hasn't been
> explicitly documented so let's add a note about that.
>
> ceph_kvmalloc is the first helper to be dropped and changed to
> kvmalloc.
>
> Signed-off-by: Michal Hocko <[email protected]>
> ---
> include/linux/ceph/libceph.h | 1 -
> mm/util.c | 15 ++++-----------
> net/ceph/buffer.c | 4 ++--
> net/ceph/ceph_common.c | 27 ---------------------------
> net/ceph/crypto.c | 2 +-
> net/ceph/messenger.c | 2 +-
> net/ceph/messenger_v2.c | 2 +-
> net/ceph/osdmap.c | 12 ++++++------
> 8 files changed, 15 insertions(+), 50 deletions(-)
>
> diff --git a/include/linux/ceph/libceph.h b/include/linux/ceph/libceph.h
> index 409d8c29bc4f..309acbcb5a8a 100644
> --- a/include/linux/ceph/libceph.h
> +++ b/include/linux/ceph/libceph.h
> @@ -295,7 +295,6 @@ extern bool libceph_compatible(void *data);
>
> extern const char *ceph_msg_type_name(int type);
> extern int ceph_check_fsid(struct ceph_client *client, struct ceph_fsid *fsid);
> -extern void *ceph_kvmalloc(size_t size, gfp_t flags);
>
> struct fs_parameter;
> struct fc_log;
> diff --git a/mm/util.c b/mm/util.c
> index bacabe446906..fdec6b4b1267 100644
> --- a/mm/util.c
> +++ b/mm/util.c
> @@ -549,13 +549,10 @@ EXPORT_SYMBOL(vm_mmap);
> * Uses kmalloc to get the memory but if the allocation fails then falls back
> * to the vmalloc allocator. Use kvfree for freeing the memory.
> *
> - * Reclaim modifiers - __GFP_NORETRY and __GFP_NOFAIL are not supported.
> + * Reclaim modifiers - __GFP_NORETRY and GFP_NOWAIT are not supported.
GFP_NOWAIT is not a modifier. It is a base value that can be modified.
I think you mean that
__GFP_NORETRY is not supported and __GFP_DIRECT_RECLAIM is required
But I really cannot see why either of these statements are true.
Before your patch, __GFP_NORETRY would have forced use of kmalloc, so
that would mean it isn't really supported. But that doesn't happen any more.
Thanks,
NeilBrown
On Tue 26-10-21 10:34:34, Neil Brown wrote:
> On Tue, 26 Oct 2021, Michal Hocko wrote:
> > From: Michal Hocko <[email protected]>
> >
> > A support for GFP_NO{FS,IO} and __GFP_NOFAIL has been implemented
> > by previous patches so we can allow the support for kvmalloc. This
> > will allow some external users to simplify or completely remove
> > their helpers.
> >
> > GFP_NOWAIT semantic hasn't been supported so far but it hasn't been
> > explicitly documented so let's add a note about that.
> >
> > ceph_kvmalloc is the first helper to be dropped and changed to
> > kvmalloc.
> >
> > Signed-off-by: Michal Hocko <[email protected]>
> > ---
> > include/linux/ceph/libceph.h | 1 -
> > mm/util.c | 15 ++++-----------
> > net/ceph/buffer.c | 4 ++--
> > net/ceph/ceph_common.c | 27 ---------------------------
> > net/ceph/crypto.c | 2 +-
> > net/ceph/messenger.c | 2 +-
> > net/ceph/messenger_v2.c | 2 +-
> > net/ceph/osdmap.c | 12 ++++++------
> > 8 files changed, 15 insertions(+), 50 deletions(-)
> >
> > diff --git a/include/linux/ceph/libceph.h b/include/linux/ceph/libceph.h
> > index 409d8c29bc4f..309acbcb5a8a 100644
> > --- a/include/linux/ceph/libceph.h
> > +++ b/include/linux/ceph/libceph.h
> > @@ -295,7 +295,6 @@ extern bool libceph_compatible(void *data);
> >
> > extern const char *ceph_msg_type_name(int type);
> > extern int ceph_check_fsid(struct ceph_client *client, struct ceph_fsid *fsid);
> > -extern void *ceph_kvmalloc(size_t size, gfp_t flags);
> >
> > struct fs_parameter;
> > struct fc_log;
> > diff --git a/mm/util.c b/mm/util.c
> > index bacabe446906..fdec6b4b1267 100644
> > --- a/mm/util.c
> > +++ b/mm/util.c
> > @@ -549,13 +549,10 @@ EXPORT_SYMBOL(vm_mmap);
> > * Uses kmalloc to get the memory but if the allocation fails then falls back
> > * to the vmalloc allocator. Use kvfree for freeing the memory.
> > *
> > - * Reclaim modifiers - __GFP_NORETRY and __GFP_NOFAIL are not supported.
> > + * Reclaim modifiers - __GFP_NORETRY and GFP_NOWAIT are not supported.
>
> GFP_NOWAIT is not a modifier. It is a base value that can be modified.
> I think you mean that
> __GFP_NORETRY is not supported and __GFP_DIRECT_RECLAIM is required
I thought naming the higher level gfp mask would be more helpful here.
Most people do not tend to think in terms of __GFP_DIRECT_RECLAIM but
rather GFP_NOWAIT or GFP_ATOMIC.
> But I really cannot see why either of these statements are true.
The reason is same as why vmalloc do not support neither of them.
> Before your patch, __GFP_NORETRY would have forced use of kmalloc, so
> that would mean it isn't really supported. But that doesn't happen any more.
__GFP_NORETRY is used internaly by kvmalloc but that doesn't mean it is
supported by the caller. In fact __GFP_NORETRY is used to implement a
higher level logic of the prioritization between kmalloc and vmalloc
fallback because some users would rather see vmalloc fallback even for
smaller allocations which do not really fail otherwise (e.g. < order-4).
--
Michal Hocko
SUSE Labs
On Tue, 26 Oct 2021, Michal Hocko wrote:
> On Tue 26-10-21 10:34:34, Neil Brown wrote:
> > On Tue, 26 Oct 2021, Michal Hocko wrote:
> > > From: Michal Hocko <[email protected]>
> > >
> > > A support for GFP_NO{FS,IO} and __GFP_NOFAIL has been implemented
> > > by previous patches so we can allow the support for kvmalloc. This
> > > will allow some external users to simplify or completely remove
> > > their helpers.
> > >
> > > GFP_NOWAIT semantic hasn't been supported so far but it hasn't been
> > > explicitly documented so let's add a note about that.
> > >
> > > ceph_kvmalloc is the first helper to be dropped and changed to
> > > kvmalloc.
> > >
> > > Signed-off-by: Michal Hocko <[email protected]>
> > > ---
> > > include/linux/ceph/libceph.h | 1 -
> > > mm/util.c | 15 ++++-----------
> > > net/ceph/buffer.c | 4 ++--
> > > net/ceph/ceph_common.c | 27 ---------------------------
> > > net/ceph/crypto.c | 2 +-
> > > net/ceph/messenger.c | 2 +-
> > > net/ceph/messenger_v2.c | 2 +-
> > > net/ceph/osdmap.c | 12 ++++++------
> > > 8 files changed, 15 insertions(+), 50 deletions(-)
> > >
> > > diff --git a/include/linux/ceph/libceph.h b/include/linux/ceph/libceph.h
> > > index 409d8c29bc4f..309acbcb5a8a 100644
> > > --- a/include/linux/ceph/libceph.h
> > > +++ b/include/linux/ceph/libceph.h
> > > @@ -295,7 +295,6 @@ extern bool libceph_compatible(void *data);
> > >
> > > extern const char *ceph_msg_type_name(int type);
> > > extern int ceph_check_fsid(struct ceph_client *client, struct ceph_fsid *fsid);
> > > -extern void *ceph_kvmalloc(size_t size, gfp_t flags);
> > >
> > > struct fs_parameter;
> > > struct fc_log;
> > > diff --git a/mm/util.c b/mm/util.c
> > > index bacabe446906..fdec6b4b1267 100644
> > > --- a/mm/util.c
> > > +++ b/mm/util.c
> > > @@ -549,13 +549,10 @@ EXPORT_SYMBOL(vm_mmap);
> > > * Uses kmalloc to get the memory but if the allocation fails then falls back
> > > * to the vmalloc allocator. Use kvfree for freeing the memory.
> > > *
> > > - * Reclaim modifiers - __GFP_NORETRY and __GFP_NOFAIL are not supported.
> > > + * Reclaim modifiers - __GFP_NORETRY and GFP_NOWAIT are not supported.
> >
> > GFP_NOWAIT is not a modifier. It is a base value that can be modified.
> > I think you mean that
> > __GFP_NORETRY is not supported and __GFP_DIRECT_RECLAIM is required
>
> I thought naming the higher level gfp mask would be more helpful here.
> Most people do not tend to think in terms of __GFP_DIRECT_RECLAIM but
> rather GFP_NOWAIT or GFP_ATOMIC.
Maybe it would. But the text says "Reclaim modifiers" and then lists
one modifier and one mask. That is confusing.
If you want to mention both, keep them separate.
GFP_NOWAIT and GFP_ATOMIC are not supported, neither is the
__GFP_NORETRY modifier.
or something like that.
Thanks,
NeilBrown
>
> > But I really cannot see why either of these statements are true.
>
> The reason is same as why vmalloc do not support neither of them.
>
> > Before your patch, __GFP_NORETRY would have forced use of kmalloc, so
> > that would mean it isn't really supported. But that doesn't happen any more.
>
> __GFP_NORETRY is used internaly by kvmalloc but that doesn't mean it is
> supported by the caller. In fact __GFP_NORETRY is used to implement a
> higher level logic of the prioritization between kmalloc and vmalloc
> fallback because some users would rather see vmalloc fallback even for
> smaller allocations which do not really fail otherwise (e.g. < order-4).
> --
> Michal Hocko
> SUSE Labs
>
>
On Tue 26-10-21 21:48:05, Neil Brown wrote:
> On Tue, 26 Oct 2021, Michal Hocko wrote:
[...]
> > > GFP_NOWAIT is not a modifier. It is a base value that can be modified.
> > > I think you mean that
> > > __GFP_NORETRY is not supported and __GFP_DIRECT_RECLAIM is required
> >
> > I thought naming the higher level gfp mask would be more helpful here.
> > Most people do not tend to think in terms of __GFP_DIRECT_RECLAIM but
> > rather GFP_NOWAIT or GFP_ATOMIC.
>
> Maybe it would. But the text says "Reclaim modifiers" and then lists
> one modifier and one mask. That is confusing.
> If you want to mention both, keep them separate.
>
> GFP_NOWAIT and GFP_ATOMIC are not supported, neither is the
> __GFP_NORETRY modifier.
>
> or something like that.
Fair enough. I went with this
commit fb93996c217cea864a3b3ffa8a8cd482bf0a1f62
Author: Michal Hocko <[email protected]>
Date: Tue Oct 26 14:23:00 2021 +0200
fold me "mm: allow !GFP_KERNEL allocations for kvmalloc"
diff --git a/mm/util.c b/mm/util.c
index fdec6b4b1267..1fb6dd907bb0 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -549,7 +549,7 @@ EXPORT_SYMBOL(vm_mmap);
* Uses kmalloc to get the memory but if the allocation fails then falls back
* to the vmalloc allocator. Use kvfree for freeing the memory.
*
- * Reclaim modifiers - __GFP_NORETRY and GFP_NOWAIT are not supported.
+ * GFP_NOWAIT and GFP_ATOMIC are not supported, neither is the __GFP_NORETRY modifier.
* __GFP_RETRY_MAYFAIL is supported, and it should be used only if kmalloc is
* preferable to the vmalloc fallback, due to visible performance drawbacks.
*
--
Michal Hocko
SUSE Labs