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linux/include/trace/events/mmflags.h
Michal Hocko 0ee931c4e3 mm: treewide: remove GFP_TEMPORARY allocation flag 
GFP_TEMPORARY was introduced by commit e12ba74d8ff3 ("Group short-lived
and reclaimable kernel allocations") along with __GFP_RECLAIMABLE.  It's
primary motivation was to allow users to tell that an allocation is
short lived and so the allocator can try to place such allocations close
together and prevent long term fragmentation.  As much as this sounds
like a reasonable semantic it becomes much less clear when to use the
highlevel GFP_TEMPORARY allocation flag.  How long is temporary? Can the
context holding that memory sleep? Can it take locks? It seems there is
no good answer for those questions.

The current implementation of GFP_TEMPORARY is basically GFP_KERNEL |
__GFP_RECLAIMABLE which in itself is tricky because basically none of
the existing caller provide a way to reclaim the allocated memory.  So
this is rather misleading and hard to evaluate for any benefits.

I have checked some random users and none of them has added the flag
with a specific justification.  I suspect most of them just copied from
other existing users and others just thought it might be a good idea to
use without any measuring.  This suggests that GFP_TEMPORARY just
motivates for cargo cult usage without any reasoning.

I believe that our gfp flags are quite complex already and especially
those with highlevel semantic should be clearly defined to prevent from
confusion and abuse.  Therefore I propose dropping GFP_TEMPORARY and
replace all existing users to simply use GFP_KERNEL.  Please note that
SLAB users with shrinkers will still get __GFP_RECLAIMABLE heuristic and
so they will be placed properly for memory fragmentation prevention.

I can see reasons we might want some gfp flag to reflect shorterm
allocations but I propose starting from a clear semantic definition and
only then add users with proper justification.

This was been brought up before LSF this year by Matthew [1] and it
turned out that GFP_TEMPORARY really doesn't have a clear semantic.  It
seems to be a heuristic without any measured advantage for most (if not
all) its current users.  The follow up discussion has revealed that
opinions on what might be temporary allocation differ a lot between
developers.  So rather than trying to tweak existing users into a
semantic which they haven't expected I propose to simply remove the flag
and start from scratch if we really need a semantic for short term
allocations.

[1] http://lkml.kernel.org/r/20170118054945.GD18349@bombadil.infradead.org

[akpm@linux-foundation.org: fix typo]
[akpm@linux-foundation.org: coding-style fixes]
[sfr@canb.auug.org.au: drm/i915: fix up]
  Link: http://lkml.kernel.org/r/20170816144703.378d4f4d@canb.auug.org.au
Link: http://lkml.kernel.org/r/20170728091904.14627-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Neil Brown <neilb@suse.de>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-13 18:53:16 -07:00

265 lines
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#include <linux/node.h>
#include <linux/mmzone.h>
#include <linux/compaction.h>
/*
* The order of these masks is important. Matching masks will be seen
* first and the left over flags will end up showing by themselves.
*
* For example, if we have GFP_KERNEL before GFP_USER we wil get:
*
* GFP_KERNEL|GFP_HARDWALL
*
* Thus most bits set go first.
*/
#define __def_gfpflag_names \
{(unsigned long)GFP_TRANSHUGE, "GFP_TRANSHUGE"}, \
{(unsigned long)GFP_TRANSHUGE_LIGHT, "GFP_TRANSHUGE_LIGHT"}, \
{(unsigned long)GFP_HIGHUSER_MOVABLE, "GFP_HIGHUSER_MOVABLE"},\
{(unsigned long)GFP_HIGHUSER, "GFP_HIGHUSER"}, \
{(unsigned long)GFP_USER, "GFP_USER"}, \
{(unsigned long)GFP_KERNEL_ACCOUNT, "GFP_KERNEL_ACCOUNT"}, \
{(unsigned long)GFP_KERNEL, "GFP_KERNEL"}, \
{(unsigned long)GFP_NOFS, "GFP_NOFS"}, \
{(unsigned long)GFP_ATOMIC, "GFP_ATOMIC"}, \
{(unsigned long)GFP_NOIO, "GFP_NOIO"}, \
{(unsigned long)GFP_NOWAIT, "GFP_NOWAIT"}, \
{(unsigned long)GFP_DMA, "GFP_DMA"}, \
{(unsigned long)__GFP_HIGHMEM, "__GFP_HIGHMEM"}, \
{(unsigned long)GFP_DMA32, "GFP_DMA32"}, \
{(unsigned long)__GFP_HIGH, "__GFP_HIGH"}, \
{(unsigned long)__GFP_ATOMIC, "__GFP_ATOMIC"}, \
{(unsigned long)__GFP_IO, "__GFP_IO"}, \
{(unsigned long)__GFP_FS, "__GFP_FS"}, \
{(unsigned long)__GFP_COLD, "__GFP_COLD"}, \
{(unsigned long)__GFP_NOWARN, "__GFP_NOWARN"}, \
{(unsigned long)__GFP_RETRY_MAYFAIL, "__GFP_RETRY_MAYFAIL"}, \
{(unsigned long)__GFP_NOFAIL, "__GFP_NOFAIL"}, \
{(unsigned long)__GFP_NORETRY, "__GFP_NORETRY"}, \
{(unsigned long)__GFP_COMP, "__GFP_COMP"}, \
{(unsigned long)__GFP_ZERO, "__GFP_ZERO"}, \
{(unsigned long)__GFP_NOMEMALLOC, "__GFP_NOMEMALLOC"}, \
{(unsigned long)__GFP_MEMALLOC, "__GFP_MEMALLOC"}, \
{(unsigned long)__GFP_HARDWALL, "__GFP_HARDWALL"}, \
{(unsigned long)__GFP_THISNODE, "__GFP_THISNODE"}, \
{(unsigned long)__GFP_RECLAIMABLE, "__GFP_RECLAIMABLE"}, \
{(unsigned long)__GFP_MOVABLE, "__GFP_MOVABLE"}, \
{(unsigned long)__GFP_ACCOUNT, "__GFP_ACCOUNT"}, \
{(unsigned long)__GFP_NOTRACK, "__GFP_NOTRACK"}, \
{(unsigned long)__GFP_WRITE, "__GFP_WRITE"}, \
{(unsigned long)__GFP_RECLAIM, "__GFP_RECLAIM"}, \
{(unsigned long)__GFP_DIRECT_RECLAIM, "__GFP_DIRECT_RECLAIM"},\
{(unsigned long)__GFP_KSWAPD_RECLAIM, "__GFP_KSWAPD_RECLAIM"}\
#define show_gfp_flags(flags) \
(flags) ? __print_flags(flags, "|", \
__def_gfpflag_names \
) : "none"
#ifdef CONFIG_MMU
#define IF_HAVE_PG_MLOCK(flag,string) ,{1UL << flag, string}
#else
#define IF_HAVE_PG_MLOCK(flag,string)
#endif
#ifdef CONFIG_ARCH_USES_PG_UNCACHED
#define IF_HAVE_PG_UNCACHED(flag,string) ,{1UL << flag, string}
#else
#define IF_HAVE_PG_UNCACHED(flag,string)
#endif
#ifdef CONFIG_MEMORY_FAILURE
#define IF_HAVE_PG_HWPOISON(flag,string) ,{1UL << flag, string}
#else
#define IF_HAVE_PG_HWPOISON(flag,string)
#endif
#if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
#define IF_HAVE_PG_IDLE(flag,string) ,{1UL << flag, string}
#else
#define IF_HAVE_PG_IDLE(flag,string)
#endif
#define __def_pageflag_names \
{1UL << PG_locked, "locked" }, \
{1UL << PG_waiters, "waiters" }, \
{1UL << PG_error, "error" }, \
{1UL << PG_referenced, "referenced" }, \
{1UL << PG_uptodate, "uptodate" }, \
{1UL << PG_dirty, "dirty" }, \
{1UL << PG_lru, "lru" }, \
{1UL << PG_active, "active" }, \
{1UL << PG_slab, "slab" }, \
{1UL << PG_owner_priv_1, "owner_priv_1" }, \
{1UL << PG_arch_1, "arch_1" }, \
{1UL << PG_reserved, "reserved" }, \
{1UL << PG_private, "private" }, \
{1UL << PG_private_2, "private_2" }, \
{1UL << PG_writeback, "writeback" }, \
{1UL << PG_head, "head" }, \
{1UL << PG_mappedtodisk, "mappedtodisk" }, \
{1UL << PG_reclaim, "reclaim" }, \
{1UL << PG_swapbacked, "swapbacked" }, \
{1UL << PG_unevictable, "unevictable" } \
IF_HAVE_PG_MLOCK(PG_mlocked, "mlocked" ) \
IF_HAVE_PG_UNCACHED(PG_uncached, "uncached" ) \
IF_HAVE_PG_HWPOISON(PG_hwpoison, "hwpoison" ) \
IF_HAVE_PG_IDLE(PG_young, "young" ) \
IF_HAVE_PG_IDLE(PG_idle, "idle" )
#define show_page_flags(flags) \
(flags) ? __print_flags(flags, "|", \
__def_pageflag_names \
) : "none"
#if defined(CONFIG_X86)
#define __VM_ARCH_SPECIFIC_1 {VM_PAT, "pat" }
#elif defined(CONFIG_PPC)
#define __VM_ARCH_SPECIFIC_1 {VM_SAO, "sao" }
#elif defined(CONFIG_PARISC) || defined(CONFIG_METAG) || defined(CONFIG_IA64)
#define __VM_ARCH_SPECIFIC_1 {VM_GROWSUP, "growsup" }
#elif !defined(CONFIG_MMU)
#define __VM_ARCH_SPECIFIC_1 {VM_MAPPED_COPY,"mappedcopy" }
#else
#define __VM_ARCH_SPECIFIC_1 {VM_ARCH_1, "arch_1" }
#endif
#ifdef CONFIG_MEM_SOFT_DIRTY
#define IF_HAVE_VM_SOFTDIRTY(flag,name) {flag, name },
#else
#define IF_HAVE_VM_SOFTDIRTY(flag,name)
#endif
#define __def_vmaflag_names \
{VM_READ, "read" }, \
{VM_WRITE, "write" }, \
{VM_EXEC, "exec" }, \
{VM_SHARED, "shared" }, \
{VM_MAYREAD, "mayread" }, \
{VM_MAYWRITE, "maywrite" }, \
{VM_MAYEXEC, "mayexec" }, \
{VM_MAYSHARE, "mayshare" }, \
{VM_GROWSDOWN, "growsdown" }, \
{VM_UFFD_MISSING, "uffd_missing" }, \
{VM_PFNMAP, "pfnmap" }, \
{VM_DENYWRITE, "denywrite" }, \
{VM_UFFD_WP, "uffd_wp" }, \
{VM_LOCKED, "locked" }, \
{VM_IO, "io" }, \
{VM_SEQ_READ, "seqread" }, \
{VM_RAND_READ, "randread" }, \
{VM_DONTCOPY, "dontcopy" }, \
{VM_DONTEXPAND, "dontexpand" }, \
{VM_LOCKONFAULT, "lockonfault" }, \
{VM_ACCOUNT, "account" }, \
{VM_NORESERVE, "noreserve" }, \
{VM_HUGETLB, "hugetlb" }, \
__VM_ARCH_SPECIFIC_1 , \
{VM_WIPEONFORK, "wipeonfork" }, \
{VM_DONTDUMP, "dontdump" }, \
IF_HAVE_VM_SOFTDIRTY(VM_SOFTDIRTY, "softdirty" ) \
{VM_MIXEDMAP, "mixedmap" }, \
{VM_HUGEPAGE, "hugepage" }, \
{VM_NOHUGEPAGE, "nohugepage" }, \
{VM_MERGEABLE, "mergeable" } \
#define show_vma_flags(flags) \
(flags) ? __print_flags(flags, "|", \
__def_vmaflag_names \
) : "none"
#ifdef CONFIG_COMPACTION
#define COMPACTION_STATUS \
EM( COMPACT_SKIPPED, "skipped") \
EM( COMPACT_DEFERRED, "deferred") \
EM( COMPACT_CONTINUE, "continue") \
EM( COMPACT_SUCCESS, "success") \
EM( COMPACT_PARTIAL_SKIPPED, "partial_skipped") \
EM( COMPACT_COMPLETE, "complete") \
EM( COMPACT_NO_SUITABLE_PAGE, "no_suitable_page") \
EM( COMPACT_NOT_SUITABLE_ZONE, "not_suitable_zone") \
EMe(COMPACT_CONTENDED, "contended")
/* High-level compaction status feedback */
#define COMPACTION_FAILED 1
#define COMPACTION_WITHDRAWN 2
#define COMPACTION_PROGRESS 3
#define compact_result_to_feedback(result) \
({ \
enum compact_result __result = result; \
(compaction_failed(__result)) ? COMPACTION_FAILED : \
(compaction_withdrawn(__result)) ? COMPACTION_WITHDRAWN : COMPACTION_PROGRESS; \
})
#define COMPACTION_FEEDBACK \
EM(COMPACTION_FAILED, "failed") \
EM(COMPACTION_WITHDRAWN, "withdrawn") \
EMe(COMPACTION_PROGRESS, "progress")
#define COMPACTION_PRIORITY \
EM(COMPACT_PRIO_SYNC_FULL, "COMPACT_PRIO_SYNC_FULL") \
EM(COMPACT_PRIO_SYNC_LIGHT, "COMPACT_PRIO_SYNC_LIGHT") \
EMe(COMPACT_PRIO_ASYNC, "COMPACT_PRIO_ASYNC")
#else
#define COMPACTION_STATUS
#define COMPACTION_PRIORITY
#define COMPACTION_FEEDBACK
#endif
#ifdef CONFIG_ZONE_DMA
#define IFDEF_ZONE_DMA(X) X
#else
#define IFDEF_ZONE_DMA(X)
#endif
#ifdef CONFIG_ZONE_DMA32
#define IFDEF_ZONE_DMA32(X) X
#else
#define IFDEF_ZONE_DMA32(X)
#endif
#ifdef CONFIG_HIGHMEM
#define IFDEF_ZONE_HIGHMEM(X) X
#else
#define IFDEF_ZONE_HIGHMEM(X)
#endif
#define ZONE_TYPE \
IFDEF_ZONE_DMA( EM (ZONE_DMA, "DMA")) \
IFDEF_ZONE_DMA32( EM (ZONE_DMA32, "DMA32")) \
EM (ZONE_NORMAL, "Normal") \
IFDEF_ZONE_HIGHMEM( EM (ZONE_HIGHMEM,"HighMem")) \
EMe(ZONE_MOVABLE,"Movable")
#define LRU_NAMES \
EM (LRU_INACTIVE_ANON, "inactive_anon") \
EM (LRU_ACTIVE_ANON, "active_anon") \
EM (LRU_INACTIVE_FILE, "inactive_file") \
EM (LRU_ACTIVE_FILE, "active_file") \
EMe(LRU_UNEVICTABLE, "unevictable")
/*
* First define the enums in the above macros to be exported to userspace
* via TRACE_DEFINE_ENUM().
*/
#undef EM
#undef EMe
#define EM(a, b) TRACE_DEFINE_ENUM(a);
#define EMe(a, b) TRACE_DEFINE_ENUM(a);
COMPACTION_STATUS
COMPACTION_PRIORITY
/* COMPACTION_FEEDBACK are defines not enums. Not needed here. */
ZONE_TYPE
LRU_NAMES
/*
* Now redefine the EM() and EMe() macros to map the enums to the strings
* that will be printed in the output.
*/
#undef EM
#undef EMe
#define EM(a, b) {a, b},
#define EMe(a, b) {a, b}
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