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Date: Fri, 13 Dec 2013 15:59:13 -0800
From: Dave Hansen <dave@...1.net>
To: linux-kernel@...r.kernel.org
Cc: linux-mm@...ck.org, Pravin B Shelar <pshelar@...ira.com>,
Christoph Lameter <cl@...ux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
Andi Kleen <ak@...ux.intel.com>, Dave Hansen <dave@...1.net>
Subject: [RFC][PATCH 7/7] mm: slub: cleanups after code churn
I added a bunch of longer than 80 column lines and other various
messes. But, doing line-to-line code replacements makes the
previous patch much easier to audit. I stuck the cleanups in
here instead.
The slub code also delcares a bunch of 'struct page's on the
stack. Now that 'struct slub_data' is separate, we can declare
those smaller structures instead. This ends up saving us a
couple hundred bytes in object size.
In the end, we take slub.o's code size from 26672->27168, so
about 500 bytes. But, on an 8GB system, we save about 256k
in 'struct page' overhead. That's a pretty good tradeoff.
Signed-off-by: Dave Hansen <dave.hansen@...ux.intel.com>
---
linux.git-davehans/mm/slub.c | 147 ++++++++++++++++++++++---------------------
1 file changed, 78 insertions(+), 69 deletions(-)
diff -puN mm/slub.c~slub-cleanups mm/slub.c
--- linux.git/mm/slub.c~slub-cleanups 2013-12-13 15:51:48.843279491 -0800
+++ linux.git-davehans/mm/slub.c 2013-12-13 15:51:48.846279622 -0800
@@ -258,7 +258,8 @@ static inline int check_valid_pointer(st
return 1;
base = page_address(page);
- if (object < base || object >= base + slub_data(page)->objects * s->size ||
+ if (object < base ||
+ object >= base + slub_data(page)->objects * s->size ||
(object - base) % s->size) {
return 0;
}
@@ -376,10 +377,11 @@ static inline bool __cmpxchg_double_slab
#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
if (s->flags & __CMPXCHG_DOUBLE) {
- if (cmpxchg_double(&slub_data(page)->freelist, &slub_data(page)->counters,
- freelist_old, counters_old,
- freelist_new, counters_new))
- return 1;
+ if (cmpxchg_double(&slub_data(page)->freelist,
+ &slub_data(page)->counters,
+ freelist_old, counters_old,
+ freelist_new, counters_new))
+ return 1;
} else
#endif
{
@@ -414,9 +416,9 @@ static inline bool cmpxchg_double_slab(s
if (s->flags & __CMPXCHG_DOUBLE) {
if (cmpxchg_double(&slub_data(page)->freelist,
&slub_data(page)->counters,
- freelist_old, counters_old,
- freelist_new, counters_new))
- return 1;
+ freelist_old, counters_old,
+ freelist_new, counters_new))
+ return 1;
} else
#endif
{
@@ -863,7 +865,8 @@ static int check_slab(struct kmem_cache
}
if (slub_data(page)->inuse > slub_data(page)->objects) {
slab_err(s, page, "inuse %u > max %u",
- s->name, slub_data(page)->inuse, slub_data(page)->objects);
+ s->name, slub_data(page)->inuse,
+ slub_data(page)->objects);
return 0;
}
/* Slab_pad_check fixes things up after itself */
@@ -894,7 +897,8 @@ static int on_freelist(struct kmem_cache
} else {
slab_err(s, page, "Freepointer corrupt");
slub_data(page)->freelist = NULL;
- slub_data(page)->inuse = slub_data(page)->objects;
+ slub_data(page)->inuse =
+ slub_data(page)->objects;
slab_fix(s, "Freelist cleared");
return 0;
}
@@ -917,7 +921,8 @@ static int on_freelist(struct kmem_cache
}
if (slub_data(page)->inuse != slub_data(page)->objects - nr) {
slab_err(s, page, "Wrong object count. Counter is %d but "
- "counted were %d", slub_data(page)->inuse, slub_data(page)->objects - nr);
+ "counted were %d", slub_data(page)->inuse,
+ slub_data(page)->objects - nr);
slub_data(page)->inuse = slub_data(page)->objects - nr;
slab_fix(s, "Object count adjusted.");
}
@@ -1554,7 +1559,7 @@ static inline void *acquire_slab(struct
{
void *freelist;
unsigned long counters;
- struct page new;
+ struct slub_data new;
/*
* Zap the freelist and set the frozen bit.
@@ -1563,22 +1568,22 @@ static inline void *acquire_slab(struct
*/
freelist = slub_data(page)->freelist;
counters = slub_data(page)->counters;
- slub_data(&new)->counters = counters;
- *objects = slub_data(&new)->objects - slub_data(&new)->inuse;
+ new.counters = counters;
+ *objects = new.objects - new.inuse;
if (mode) {
- slub_data(&new)->inuse = slub_data(page)->objects;
- slub_data(&new)->freelist = NULL;
+ new.inuse = slub_data(page)->objects;
+ new.freelist = NULL;
} else {
- slub_data(&new)->freelist = freelist;
+ new.freelist = freelist;
}
- VM_BUG_ON(slub_data(&new)->frozen);
- slub_data(&new)->frozen = 1;
+ VM_BUG_ON(new.frozen);
+ new.frozen = 1;
if (!__cmpxchg_double_slab(s, page,
freelist, counters,
- slub_data(&new)->freelist,
- slub_data(&new)->counters,
+ new.freelist,
+ new.counters,
"acquire_slab"))
return NULL;
@@ -1800,8 +1805,8 @@ static void deactivate_slab(struct kmem_
enum slab_modes l = M_NONE, m = M_NONE;
void *nextfree;
int tail = DEACTIVATE_TO_HEAD;
- struct page new;
- struct page old;
+ struct slub_data new;
+ struct slub_data old;
if (slub_data(page)->freelist) {
stat(s, DEACTIVATE_REMOTE_FREES);
@@ -1824,13 +1829,13 @@ static void deactivate_slab(struct kmem_
prior = slub_data(page)->freelist;
counters = slub_data(page)->counters;
set_freepointer(s, freelist, prior);
- slub_data(&new)->counters = counters;
- slub_data(&new)->inuse--;
- VM_BUG_ON(!slub_data(&new)->frozen);
+ new.counters = counters;
+ new.inuse--;
+ VM_BUG_ON(!new.frozen);
} while (!__cmpxchg_double_slab(s, page,
prior, counters,
- freelist, slub_data(&new)->counters,
+ freelist, new.counters,
"drain percpu freelist"));
freelist = nextfree;
@@ -1852,24 +1857,24 @@ static void deactivate_slab(struct kmem_
*/
redo:
- slub_data(&old)->freelist = slub_data(page)->freelist;
- slub_data(&old)->counters = slub_data(page)->counters;
- VM_BUG_ON(!slub_data(&old)->frozen);
+ old.freelist = slub_data(page)->freelist;
+ old.counters = slub_data(page)->counters;
+ VM_BUG_ON(!old.frozen);
/* Determine target state of the slab */
- slub_data(&new)->counters = slub_data(&old)->counters;
+ new.counters = old.counters;
if (freelist) {
- slub_data(&new)->inuse--;
- set_freepointer(s, freelist, slub_data(&old)->freelist);
- slub_data(&new)->freelist = freelist;
+ new.inuse--;
+ set_freepointer(s, freelist, old.freelist);
+ new.freelist = freelist;
} else
- slub_data(&new)->freelist = slub_data(&old)->freelist;
+ new.freelist = old.freelist;
- slub_data(&new)->frozen = 0;
+ new.frozen = 0;
- if (!slub_data(&new)->inuse && n->nr_partial > s->min_partial)
+ if (!new.inuse && n->nr_partial > s->min_partial)
m = M_FREE;
- else if (slub_data(&new)->freelist) {
+ else if (new.freelist) {
m = M_PARTIAL;
if (!lock) {
lock = 1;
@@ -1918,8 +1923,10 @@ redo:
l = m;
if (!__cmpxchg_double_slab(s, page,
- slub_data(&old)->freelist, slub_data(&old)->counters,
- slub_data(&new)->freelist, slub_data(&new)->counters,
+ old.freelist,
+ old.counters,
+ new.freelist,
+ new.counters,
"unfreezing slab"))
goto redo;
@@ -1948,8 +1955,8 @@ static void unfreeze_partials(struct kme
struct page *page, *discard_page = NULL;
while ((page = c->partial)) {
- struct page new;
- struct page old;
+ struct slub_data new;
+ struct slub_data old;
c->partial = page->next;
@@ -1964,23 +1971,24 @@ static void unfreeze_partials(struct kme
do {
- slub_data(&old)->freelist = slub_data(page)->freelist;
- slub_data(&old)->counters = slub_data(page)->counters;
- VM_BUG_ON(!slub_data(&old)->frozen);
+ old.freelist = slub_data(page)->freelist;
+ old.counters = slub_data(page)->counters;
+ VM_BUG_ON(!old.frozen);
- slub_data(&new)->counters = slub_data(&old)->counters;
- slub_data(&new)->freelist = slub_data(&old)->freelist;
+ new.counters = old.counters;
+ new.freelist = old.freelist;
- slub_data(&new)->frozen = 0;
+ new.frozen = 0;
} while (!__cmpxchg_double_slab(s, page,
- slub_data(&old)->freelist,
- slub_data(&old)->counters,
- slub_data(&new)->freelist,
- slub_data(&new)->counters,
+ old.freelist,
+ old.counters,
+ new.freelist,
+ new.counters,
"unfreezing slab"));
- if (unlikely(!slub_data(&new)->inuse && n->nr_partial > s->min_partial)) {
+ if (unlikely(!new.inuse &&
+ n->nr_partial > s->min_partial)) {
page->next = discard_page;
discard_page = page;
} else {
@@ -2232,7 +2240,7 @@ static inline bool pfmemalloc_match(stru
*/
static inline void *get_freelist(struct kmem_cache *s, struct page *page)
{
- struct page new;
+ struct slub_data new;
unsigned long counters;
void *freelist;
@@ -2240,15 +2248,15 @@ static inline void *get_freelist(struct
freelist = slub_data(page)->freelist;
counters = slub_data(page)->counters;
- slub_data(&new)->counters = counters;
- VM_BUG_ON(!slub_data(&new)->frozen);
+ new.counters = counters;
+ VM_BUG_ON(!new.frozen);
- slub_data(&new)->inuse = slub_data(page)->objects;
- slub_data(&new)->frozen = freelist != NULL;
+ new.inuse = slub_data(page)->objects;
+ new.frozen = freelist != NULL;
} while (!__cmpxchg_double_slab(s, page,
freelist, counters,
- NULL, slub_data(&new)->counters,
+ NULL, new.counters,
"get_freelist"));
return freelist;
@@ -2533,7 +2541,7 @@ static void __slab_free(struct kmem_cach
void *prior;
void **object = (void *)x;
int was_frozen;
- struct page new;
+ struct slub_data new;
unsigned long counters;
struct kmem_cache_node *n = NULL;
unsigned long uninitialized_var(flags);
@@ -2552,10 +2560,10 @@ static void __slab_free(struct kmem_cach
prior = slub_data(page)->freelist;
counters = slub_data(page)->counters;
set_freepointer(s, object, prior);
- slub_data(&new)->counters = counters;
- was_frozen = slub_data(&new)->frozen;
- slub_data(&new)->inuse--;
- if ((!slub_data(&new)->inuse || !prior) && !was_frozen) {
+ new.counters = counters;
+ was_frozen = new.frozen;
+ new.inuse--;
+ if ((!new.inuse || !prior) && !was_frozen) {
if (kmem_cache_has_cpu_partial(s) && !prior)
@@ -2565,7 +2573,7 @@ static void __slab_free(struct kmem_cach
* We can defer the list move and instead
* freeze it.
*/
- slub_data(&new)->frozen = 1;
+ new.frozen = 1;
else { /* Needs to be taken off a list */
@@ -2585,7 +2593,7 @@ static void __slab_free(struct kmem_cach
} while (!cmpxchg_double_slab(s, page,
prior, counters,
- object, slub_data(&new)->counters,
+ object, new.counters,
"__slab_free"));
if (likely(!n)) {
@@ -2594,7 +2602,7 @@ static void __slab_free(struct kmem_cach
* If we just froze the page then put it onto the
* per cpu partial list.
*/
- if (slub_data(&new)->frozen && !was_frozen) {
+ if (new.frozen && !was_frozen) {
put_cpu_partial(s, page, 1);
stat(s, CPU_PARTIAL_FREE);
}
@@ -2607,7 +2615,7 @@ static void __slab_free(struct kmem_cach
return;
}
- if (unlikely(!slub_data(&new)->inuse && n->nr_partial > s->min_partial))
+ if (unlikely(!new.inuse && n->nr_partial > s->min_partial))
goto slab_empty;
/*
@@ -3431,7 +3439,8 @@ int kmem_cache_shrink(struct kmem_cache
* list_lock. ->inuse here is the upper limit.
*/
list_for_each_entry_safe(page, t, &n->partial, lru) {
- list_move(&page->lru, slabs_by_inuse + slub_data(page)->inuse);
+ list_move(&page->lru, slabs_by_inuse +
+ slub_data(page)->inuse);
if (!slub_data(page)->inuse)
n->nr_partial--;
}
_
--
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