| Message ID | 20211025150223.13621-5-mhocko@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | extend vmalloc support for constrained allocations | expand |
On Tue, 26 Oct 2021, Michal Hocko wrote: > From: Michal Hocko <mhocko@suse.com> > > 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 <mhocko@suse.com> > --- > 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 <mhocko@suse.com> > > > > 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 <mhocko@suse.com> > > --- > > 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).
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 <mhocko@suse.com> > > > > > > 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 <mhocko@suse.com> > > > --- > > > 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 <mhocko@suse.com> 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. *
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)