Commit 32d6bd90 authored by Michal Hocko's avatar Michal Hocko Committed by Linus Torvalds
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tree wide: get rid of __GFP_REPEAT for order-0 allocations part I

This is the third version of the patchset previously sent [1].  I have
basically only rebased it on top of 4.7-rc1 tree and dropped "dm: get
rid of superfluous gfp flags" which went through dm tree.  I am sending
it now because it is tree wide and chances for conflicts are reduced
considerably when we want to target rc2.  I plan to send the next step
and rename the flag and move to a better semantic later during this
release cycle so we will have a new semantic ready for 4.8 merge window
hopefully.

Motivation:

While working on something unrelated I've checked the current usage of
__GFP_REPEAT in the tree.  It seems that a majority of the usage is and
always has been bogus because __GFP_REPEAT has always been about costly
high order allocations while we are using it for order-0 or very small
orders very often.  It seems that a big pile of them is just a
copy&paste when a code has been adopted from one arch to another.

I think it makes some sense to get rid of them because they are just
making the semantic more unclear.  Please note that GFP_REPEAT is
documented as

* __GFP_REPEAT: Try hard to allocate the memory, but the allocation attempt

* _might_ fail.  This depends upon the particular VM implementation.
  while !costly requests have basically nofail semantic.  So one could
  reasonably expect that order-0 request with __GFP_REPEAT will not loop
  for ever.  This is not implemented right now though.

I would like to move on with __GFP_REPEAT and define a better semantic
for it.

  $ git grep __GFP_REPEAT origin/master | wc -l
  111
  $ git grep __GFP_REPEAT | wc -l
  36

So we are down to the third after this patch series.  The remaining
places really seem to be relying on __GFP_REPEAT due to large allocation
requests.  This still needs some double checking which I will do later
after all the simple ones are sorted out.

I am touching a lot of arch specific code here and I hope I got it right
but as a matter of fact I even didn't compile test for some archs as I
do not have cross compiler for them.  Patches should be quite trivial to
review for stupid compile mistakes though.  The tricky parts are usually
hidden by macro definitions and thats where I would appreciate help from
arch maintainers.

[1] http://lkml.kernel.org/r/1461849846-27209-1-git-send-email-mhocko@kernel.org

This patch (of 19):

__GFP_REPEAT has a rather weak semantic but since it has been introduced
around 2.6.12 it has been ignored for low order allocations.  Yet we
have the full kernel tree with its usage for apparently order-0
allocations.  This is really confusing because __GFP_REPEAT is
explicitly documented to allow allocation failures which is a weaker
semantic than the current order-0 has (basically nofail).

Let's simply drop __GFP_REPEAT from those places.  This would allow to
identify place which really need allocator to retry harder and formulate
a more specific semantic for what the flag is supposed to do actually.

Link: http://lkml.kernel.org/r/1464599699-30131-2-git-send-email-mhocko@kernel.org


Signed-off-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com> [for tile]
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: John Crispin <blogic@openwrt.org>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b9b4bb26
......@@ -40,7 +40,7 @@ pgd_free(struct mm_struct *mm, pgd_t *pgd)
static inline pmd_t *
pmd_alloc_one(struct mm_struct *mm, unsigned long address)
{
pmd_t *ret = (pmd_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
pmd_t *ret = (pmd_t *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
return ret;
}
......@@ -53,7 +53,7 @@ pmd_free(struct mm_struct *mm, pmd_t *pmd)
static inline pte_t *
pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
{
pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
return pte;
}
......
......@@ -29,7 +29,7 @@
static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
{
return (pmd_t *)get_zeroed_page(GFP_KERNEL | __GFP_REPEAT);
return (pmd_t *)get_zeroed_page(GFP_KERNEL);
}
static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
......
......@@ -43,7 +43,7 @@ static inline void pgd_ctor(void *x)
*/
static inline pgd_t *pgd_alloc(struct mm_struct *mm)
{
return quicklist_alloc(QUICK_PGD, GFP_KERNEL | __GFP_REPEAT, pgd_ctor);
return quicklist_alloc(QUICK_PGD, GFP_KERNEL, pgd_ctor);
}
static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
......@@ -54,7 +54,7 @@ static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
unsigned long address)
{
return quicklist_alloc(QUICK_PT, GFP_KERNEL | __GFP_REPEAT, NULL);
return quicklist_alloc(QUICK_PT, GFP_KERNEL, NULL);
}
static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
......@@ -63,7 +63,7 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
struct page *page;
void *pg;
pg = quicklist_alloc(QUICK_PT, GFP_KERNEL | __GFP_REPEAT, NULL);
pg = quicklist_alloc(QUICK_PT, GFP_KERNEL, NULL);
if (!pg)
return NULL;
......
......@@ -24,14 +24,14 @@ static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
{
pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
return pte;
}
static inline pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
{
struct page *pte;
pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 0);
pte = alloc_pages(GFP_KERNEL|__GFP_ZERO, 0);
if (!pte)
return NULL;
if (!pgtable_page_ctor(pte)) {
......
......@@ -22,7 +22,7 @@ pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__((aligned(PAGE_SIZE)));
pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
{
pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT);
pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL);
if (pte)
clear_page(pte);
return pte;
......@@ -33,9 +33,9 @@ pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
struct page *page;
#ifdef CONFIG_HIGHPTE
page = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT, 0);
page = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM, 0);
#else
page = alloc_pages(GFP_KERNEL|__GFP_REPEAT, 0);
page = alloc_pages(GFP_KERNEL, 0);
#endif
if (!page)
return NULL;
......
......@@ -64,7 +64,7 @@ static inline struct page *pte_alloc_one(struct mm_struct *mm,
{
struct page *pte;
pte = alloc_page(GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO);
pte = alloc_page(GFP_KERNEL | __GFP_ZERO);
if (!pte)
return NULL;
if (!pgtable_page_ctor(pte)) {
......@@ -78,7 +78,7 @@ static inline struct page *pte_alloc_one(struct mm_struct *mm,
static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
unsigned long address)
{
gfp_t flags = GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO;
gfp_t flags = GFP_KERNEL | __GFP_ZERO;
return (pte_t *) __get_free_page(flags);
}
......
......@@ -14,7 +14,7 @@ extern const char bad_pmd_string[];
extern inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
unsigned long address)
{
unsigned long page = __get_free_page(GFP_DMA|__GFP_REPEAT);
unsigned long page = __get_free_page(GFP_DMA);
if (!page)
return NULL;
......@@ -51,7 +51,7 @@ static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t page,
static inline struct page *pte_alloc_one(struct mm_struct *mm,
unsigned long address)
{
struct page *page = alloc_pages(GFP_DMA|__GFP_REPEAT, 0);
struct page *page = alloc_pages(GFP_DMA, 0);
pte_t *pte;
if (!page)
......
......@@ -11,7 +11,7 @@ static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long ad
{
pte_t *pte;
pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
if (pte) {
__flush_page_to_ram(pte);
flush_tlb_kernel_page(pte);
......@@ -32,7 +32,7 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long addres
struct page *page;
pte_t *pte;
page = alloc_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 0);
page = alloc_pages(GFP_KERNEL|__GFP_ZERO, 0);
if(!page)
return NULL;
if (!pgtable_page_ctor(page)) {
......
......@@ -37,7 +37,7 @@ do { \
static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
unsigned long address)
{
unsigned long page = __get_free_page(GFP_KERNEL|__GFP_REPEAT);
unsigned long page = __get_free_page(GFP_KERNEL);
if (!page)
return NULL;
......@@ -49,7 +49,7 @@ static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
unsigned long address)
{
struct page *page = alloc_pages(GFP_KERNEL|__GFP_REPEAT, 0);
struct page *page = alloc_pages(GFP_KERNEL, 0);
if (page == NULL)
return NULL;
......
......@@ -42,8 +42,7 @@ static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
unsigned long address)
{
pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL | __GFP_REPEAT |
__GFP_ZERO);
pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
return pte;
}
......@@ -51,7 +50,7 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
unsigned long address)
{
struct page *pte;
pte = alloc_pages(GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO, 0);
pte = alloc_pages(GFP_KERNEL | __GFP_ZERO, 0);
if (!pte)
return NULL;
if (!pgtable_page_ctor(pte)) {
......
......@@ -116,9 +116,9 @@ static inline struct page *pte_alloc_one(struct mm_struct *mm,
struct page *ptepage;
#ifdef CONFIG_HIGHPTE
int flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_REPEAT;
int flags = GFP_KERNEL | __GFP_HIGHMEM;
#else
int flags = GFP_KERNEL | __GFP_REPEAT;
int flags = GFP_KERNEL;
#endif
ptepage = alloc_pages(flags, 0);
......
......@@ -239,8 +239,7 @@ __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
{
pte_t *pte;
if (mem_init_done) {
pte = (pte_t *)__get_free_page(GFP_KERNEL |
__GFP_REPEAT | __GFP_ZERO);
pte = (pte_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
} else {
pte = (pte_t *)early_get_page();
if (pte)
......
......@@ -63,7 +63,7 @@ void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
{
pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT);
pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL);
if (pte)
clear_page(pte);
return pte;
......@@ -74,9 +74,9 @@ struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
struct page *pte;
#ifdef CONFIG_HIGHPTE
pte = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT, 0);
pte = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM, 0);
#else
pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT, 0);
pte = alloc_pages(GFP_KERNEL, 0);
#endif
if (!pte)
return NULL;
......
......@@ -77,7 +77,7 @@ static inline struct page *pte_alloc_one(struct mm_struct *mm,
unsigned long address)
{
struct page *pte;
pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT, 0);
pte = alloc_pages(GFP_KERNEL, 0);
if (!pte)
return NULL;
clear_page(page_address(pte));
......
......@@ -122,7 +122,7 @@ pte_t __init_refok *pte_alloc_one_kernel(struct mm_struct *mm,
pte_t *pte;
if (likely(mem_init_done)) {
pte = (pte_t *) __get_free_page(GFP_KERNEL | __GFP_REPEAT);
pte = (pte_t *) __get_free_page(GFP_KERNEL);
} else {
pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
#if 0
......
......@@ -124,7 +124,7 @@ pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
static inline pgtable_t
pte_alloc_one(struct mm_struct *mm, unsigned long address)
{
struct page *page = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
struct page *page = alloc_page(GFP_KERNEL|__GFP_ZERO);
if (!page)
return NULL;
if (!pgtable_page_ctor(page)) {
......@@ -137,7 +137,7 @@ pte_alloc_one(struct mm_struct *mm, unsigned long address)
static inline pte_t *
pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr)
{
pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
return pte;
}
......
......@@ -151,7 +151,7 @@ static inline pgtable_t pmd_pgtable(pmd_t pmd)
static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
unsigned long address)
{
return (pte_t *)__get_free_page(GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO);
return (pte_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
}
static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
......
......@@ -88,7 +88,7 @@ static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
unsigned long address)
{
return (pte_t *)__get_free_page(GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO);
return (pte_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
}
static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
......
......@@ -84,7 +84,7 @@ __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long add
pte_t *pte;
if (slab_is_available()) {
pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
} else {
pte = __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE));
if (pte)
......@@ -97,7 +97,7 @@ pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
{
struct page *ptepage;
gfp_t flags = GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO;
gfp_t flags = GFP_KERNEL | __GFP_ZERO;
ptepage = alloc_pages(flags, 0);
if (!ptepage)
......
......@@ -350,8 +350,7 @@ static pte_t *get_from_cache(struct mm_struct *mm)
static pte_t *__alloc_for_cache(struct mm_struct *mm, int kernel)
{
void *ret = NULL;
struct page *page = alloc_page(GFP_KERNEL | __GFP_NOTRACK |
__GFP_REPEAT | __GFP_ZERO);
struct page *page = alloc_page(GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO);
if (!page)
return NULL;
if (!kernel && !pgtable_page_ctor(page)) {
......
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