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Remove KMC_OFFSLAB 

Remove dead code to make the implementation easier to understand.

Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Ahrens <matt@delphix.com>
Closes #10650
This commit is contained in:
Matthew Ahrens 2020-07-29 22:03:23 -07:00 committed by Brian Behlendorf
parent d87676a9fa
commit 492db125dc
2 changed files with 39 additions and 96 deletions
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2
include/os/linux/spl/sys/kmem_cache.h
View File

@ -45,7 +45,6 @@ typedef enum kmc_bit {
KMC_BIT_VMEM = 6, /* Use vmem cache */
KMC_BIT_KVMEM = 7, /* Use kvmalloc linux allocator */
KMC_BIT_SLAB = 8, /* Use Linux slab cache */
KMC_BIT_OFFSLAB = 9, /* Objects not on slab */
KMC_BIT_DEADLOCKED = 14, /* Deadlock detected */
KMC_BIT_GROWING = 15, /* Growing in progress */
KMC_BIT_REAPING = 16, /* Reaping in progress */
@ -73,7 +72,6 @@ typedef enum kmem_cbrc {
#define KMC_VMEM (1 << KMC_BIT_VMEM)
#define KMC_KVMEM (1 << KMC_BIT_KVMEM)
#define KMC_SLAB (1 << KMC_BIT_SLAB)
#define KMC_OFFSLAB (1 << KMC_BIT_OFFSLAB)
#define KMC_DEADLOCKED (1 << KMC_BIT_DEADLOCKED)
#define KMC_GROWING (1 << KMC_BIT_GROWING)
#define KMC_REAPING (1 << KMC_BIT_REAPING)

133
module/os/linux/spl/spl-kmem-cache.c
View File

@ -259,16 +259,6 @@ spl_sko_from_obj(spl_kmem_cache_t *skc, void *obj)
skc->skc_obj_align, uint32_t));
}
/*
* Required space for each offslab object taking in to account alignment
* restrictions and the power-of-two requirement of kv_alloc().
*/
static inline uint32_t
spl_offslab_size(spl_kmem_cache_t *skc)
{
return (1UL << (fls64(spl_obj_size(skc)) + 1));
}
/*
* It's important that we pack the spl_kmem_obj_t structure and the
* actual objects in to one large address space to minimize the number
@ -289,25 +279,21 @@ spl_offslab_size(spl_kmem_cache_t *skc)
* different allocation functions for small and large objects should
* give us the best of both worlds.
*
* KMC_ONSLAB KMC_OFFSLAB
*
* +------------------------+ +-----------------+
* | spl_kmem_slab_t --+-+ | | spl_kmem_slab_t |---+-+
* | skc_obj_size <-+ | | +-----------------+ | |
* | spl_kmem_obj_t | | | |
* | skc_obj_size <---+ | +-----------------+ | |
* | spl_kmem_obj_t | | | skc_obj_size | <-+ |
* | ... v | | spl_kmem_obj_t | |
* +------------------------+ +-----------------+ v
* +------------------------+
* | spl_kmem_slab_t --+-+ |
* | skc_obj_size <-+ | |
* | spl_kmem_obj_t | |
* | skc_obj_size <---+ |
* | spl_kmem_obj_t | |
* | ... v |
* +------------------------+
*/
static spl_kmem_slab_t *
spl_slab_alloc(spl_kmem_cache_t *skc, int flags)
{
spl_kmem_slab_t *sks;
spl_kmem_obj_t *sko;
void *base, *obj;
uint32_t obj_size, offslab_size = 0;
int i, rc = 0;
void *base;
uint32_t obj_size;
base = kv_alloc(skc, skc->skc_slab_size, flags);
if (base == NULL)
@ -323,22 +309,11 @@ spl_slab_alloc(spl_kmem_cache_t *skc, int flags)
sks->sks_ref = 0;
obj_size = spl_obj_size(skc);
if (skc->skc_flags & KMC_OFFSLAB)
offslab_size = spl_offslab_size(skc);
for (i = 0; i < sks->sks_objs; i++) {
if (skc->skc_flags & KMC_OFFSLAB) {
obj = kv_alloc(skc, offslab_size, flags);
if (!obj) {
rc = -ENOMEM;
goto out;
}
} else {
obj = base + spl_sks_size(skc) + (i * obj_size);
}
for (int i = 0; i < sks->sks_objs; i++) {
void *obj = base + spl_sks_size(skc) + (i * obj_size);
ASSERT(IS_P2ALIGNED(obj, skc->skc_obj_align));
sko = spl_sko_from_obj(skc, obj);
spl_kmem_obj_t *sko = spl_sko_from_obj(skc, obj);
sko->sko_addr = obj;
sko->sko_magic = SKO_MAGIC;
sko->sko_slab = sks;
@ -346,19 +321,6 @@ spl_slab_alloc(spl_kmem_cache_t *skc, int flags)
list_add_tail(&sko->sko_list, &sks->sks_free_list);
}
out:
if (rc) {
spl_kmem_obj_t *n = NULL;
if (skc->skc_flags & KMC_OFFSLAB)
list_for_each_entry_safe(sko,
n, &sks->sks_free_list, sko_list) {
kv_free(skc, sko->sko_addr, offslab_size);
}
kv_free(skc, base, skc->skc_slab_size);
sks = NULL;
}
return (sks);
}
@ -402,7 +364,6 @@ spl_slab_reclaim(spl_kmem_cache_t *skc)
spl_kmem_obj_t *sko = NULL, *n = NULL;
LIST_HEAD(sks_list);
LIST_HEAD(sko_list);
uint32_t size = 0;
/*
* Empty slabs and objects must be moved to a private list so they
@ -422,21 +383,15 @@ spl_slab_reclaim(spl_kmem_cache_t *skc)
spin_unlock(&skc->skc_lock);
/*
* The following two loops ensure all the object destructors are
* run, any offslab objects are freed, and the slabs themselves
* are freed. This is all done outside the skc->skc_lock since
* this allows the destructor to sleep, and allows us to perform
* a conditional reschedule when a freeing a large number of
* objects and slabs back to the system.
* The following two loops ensure all the object destructors are run,
* and the slabs themselves are freed. This is all done outside the
* skc->skc_lock since this allows the destructor to sleep, and
* allows us to perform a conditional reschedule when a freeing a
* large number of objects and slabs back to the system.
*/
if (skc->skc_flags & KMC_OFFSLAB)
size = spl_offslab_size(skc);
list_for_each_entry_safe(sko, n, &sko_list, sko_list) {
ASSERT(sko->sko_magic == SKO_MAGIC);
if (skc->skc_flags & KMC_OFFSLAB)
kv_free(skc, sko->sko_addr, size);
}
list_for_each_entry_safe(sks, m, &sks_list, sks_list) {
@ -603,37 +558,28 @@ spl_slab_size(spl_kmem_cache_t *skc, uint32_t *objs, uint32_t *size)
{
uint32_t sks_size, obj_size, max_size, tgt_size, tgt_objs;
if (skc->skc_flags & KMC_OFFSLAB) {
tgt_objs = spl_kmem_cache_obj_per_slab;
tgt_size = P2ROUNDUP(sizeof (spl_kmem_slab_t), PAGE_SIZE);
sks_size = spl_sks_size(skc);
obj_size = spl_obj_size(skc);
max_size = (spl_kmem_cache_max_size * 1024 * 1024);
tgt_size = (spl_kmem_cache_obj_per_slab * obj_size + sks_size);
if ((skc->skc_flags & KMC_KMEM) &&
(spl_obj_size(skc) > (SPL_MAX_ORDER_NR_PAGES * PAGE_SIZE)))
return (-ENOSPC);
/*
* KMC_KMEM slabs are allocated by __get_free_pages() which
* rounds up to the nearest order. Knowing this the size
* should be rounded up to the next power of two with a hard
* maximum defined by the maximum allowed allocation order.
*/
if (skc->skc_flags & KMC_KMEM) {
max_size = SPL_MAX_ORDER_NR_PAGES * PAGE_SIZE;
tgt_size = MIN(max_size,
PAGE_SIZE * (1 << MAX(get_order(tgt_size) - 1, 1)));
}
if (tgt_size <= max_size) {
tgt_objs = (tgt_size - sks_size) / obj_size;
} else {
sks_size = spl_sks_size(skc);
obj_size = spl_obj_size(skc);
max_size = (spl_kmem_cache_max_size * 1024 * 1024);
tgt_size = (spl_kmem_cache_obj_per_slab * obj_size + sks_size);
/*
* KMC_KMEM slabs are allocated by __get_free_pages() which
* rounds up to the nearest order. Knowing this the size
* should be rounded up to the next power of two with a hard
* maximum defined by the maximum allowed allocation order.
*/
if (skc->skc_flags & KMC_KMEM) {
max_size = SPL_MAX_ORDER_NR_PAGES * PAGE_SIZE;
tgt_size = MIN(max_size,
PAGE_SIZE * (1 << MAX(get_order(tgt_size) - 1, 1)));
}
if (tgt_size <= max_size) {
tgt_objs = (tgt_size - sks_size) / obj_size;
} else {
tgt_objs = (max_size - sks_size) / obj_size;
tgt_size = (tgt_objs * obj_size) + sks_size;
}
tgt_objs = (max_size - sks_size) / obj_size;
tgt_size = (tgt_objs * obj_size) + sks_size;
}
if (tgt_objs == 0)
@ -772,9 +718,8 @@ spl_magazine_destroy(spl_kmem_cache_t *skc)
* flags
* KMC_KMEM Force SPL kmem backed cache
* KMC_VMEM Force SPL vmem backed cache
* KMC_KVMEM Force kvmem backed cache
* KMC_KVMEM Force kvmem backed SPL cache
* KMC_SLAB Force Linux slab backed cache
* KMC_OFFSLAB Locate objects off the slab
* KMC_NOTOUCH Disable cache object aging (unsupported)
* KMC_NODEBUG Disable debugging (unsupported)
* KMC_NOHASH Disable hashing (unsupported)