mm-discard-__gfp_atomic.patch removed from -mm tree
The quilt patch titled
Subject: mm: discard __GFP_ATOMIC
has been removed from the -mm tree. Its filename was
mm-discard-__gfp_atomic.patch
This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: NeilBrown <[email protected]>
Subject: mm: discard __GFP_ATOMIC
Date: Fri, 13 Jan 2023 11:12:17 +0000
__GFP_ATOMIC serves little purpose. Its main effect is to set ALLOC_HARDER which adds a few little boosts to increase the chance of an allocation succeeding, one of which is to lower the water-mark at which it will succeed.
It is *always* paired with __GFP_HIGH which sets ALLOC_HIGH which also adjusts this watermark. It is probable that other users of __GFP_HIGH should benefit from the other little bonuses that __GFP_ATOMIC gets.
__GFP_ATOMIC also gives a warning if used with __GFP_DIRECT_RECLAIM. There is little point to this. We already get a might_sleep() warning if __GFP_DIRECT_RECLAIM is set.
__GFP_ATOMIC allows the "watermark_boost" to be side-stepped. It is probable that testing ALLOC_HARDER is a better fit here.
__GFP_ATOMIC is used by tegra-smmu.c to check if the allocation might sleep. This should test __GFP_DIRECT_RECLAIM instead.
This patch:
- removes __GFP_ATOMIC
- allows __GFP_HIGH allocations to ignore watermark boosting as well as GFP_ATOMIC requests.
- makes other adjustments as suggested by the above.
The net result is not change to GFP_ATOMIC allocations. Other allocations that use __GFP_HIGH will benefit from a few different extra privileges. This affects:
xen, dm, md, ntfs3
the vermillion frame buffer
hibernation
ksm
swap
all of which likely produce more benefit than cost if these selected allocation are more likely to succeed quickly.
---
Documentation/mm/balance.rst renamed from Documentation/mm/balance.rst~mm-discard-__gfp_atomic +1 -1
@@ -6,7 +6,7 @@ Memory Balancing Started Jan 2000 by Kanoj Sarcar <[email protected]> -Memory balancing is needed for !__GFP_ATOMIC and !__GFP_KSWAPD_RECLAIM as +Memory balancing is needed for !__GFP_HIGH and !__GFP_KSWAPD_RECLAIM as well as for non __GFP_IO allocations. The first reason why a caller may avoid reclaim is that the caller can not
drivers/iommu/tegra-smmu.c renamed from drivers/iommu/tegra-smmu.c~mm-discard-__gfp_atomic +2 -2
@@ -671,12 +671,12 @@ static struct page *as_get_pde_page(stru* allocate page in a sleeping context if GFP flags permit. Hence * spinlock needs to be unlocked and re-locked after allocation. */ -if (!(gfp & __GFP_ATOMIC)) +if (gfpflags_allow_blocking (gfp))spin_unlock_irqrestore (&as->lock, *flags); page =alloc_page (gfp | __GFP_DMA | __GFP_ZERO); -if (!(gfp & __GFP_ATOMIC)) +if (gfpflags_allow_blocking (gfp))spin_lock_irqsave (&as->lock, *flags);/*
include/linux/gfp_types.h renamed from include/linux/gfp_types.h~mm-discard-__gfp_atomic +4 -8
@@ -31,7 +31,7 @@ typedef unsigned int __bitwise gfp_t;#define ___GFP_IO 0x40u#define ___GFP_FS 0x80u#define ___GFP_ZERO 0x100u -#define ___GFP_ATOMIC 0x200u +/* 0x200u unused */ #define ___GFP_DIRECT_RECLAIM 0x400u#define ___GFP_KSWAPD_RECLAIM 0x800u#define ___GFP_WRITE 0x1000u
@@ -116,11 +116,8 @@ typedef unsigned int __bitwise gfp_t;* * %__GFP_HIGH indicates that the caller is high-priority and that granting * the request is necessary before the system can make forward progress. -* For example, creating an IO context to clean pages. -* -* %__GFP_ATOMIC indicates that the caller cannot reclaim or sleep and is -* high priority. Users are typically interrupt handlers. This may be -* used in conjunction with %__GFP_HIGH +* For example creating an IO context to clean pages and requests +* from atomic context. * * %__GFP_MEMALLOC allows access to all memory. This should only be used when * the caller guarantees the allocation will allow more memory to be freed
@@ -135,7 +132,6 @@ typedef unsigned int __bitwise gfp_t;* %__GFP_NOMEMALLOC is used to explicitly forbid access to emergency reserves. * This takes precedence over the %__GFP_MEMALLOC flag if both are set. */ -#define __GFP_ATOMIC ((__force gfp_t)___GFP_ATOMIC)#define __GFP_HIGH ((__force gfp_t)___GFP_HIGH)#define __GFP_MEMALLOC ((__force gfp_t)___GFP_MEMALLOC)#define __GFP_NOMEMALLOC ((__force gfp_t)___GFP_NOMEMALLOC)
@@ -329,7 +325,7 @@ typedef unsigned int __bitwise gfp_t;* version does not attempt reclaim/compaction at all and is by default used * in page fault path, while the non-light is used by khugepaged. */ -#define GFP_ATOMIC (__GFP_HIGH|__GFP_ATOMIC|__GFP_KSWAPD_RECLAIM) +#define GFP_ATOMIC (__GFP_HIGH|__GFP_KSWAPD_RECLAIM)#define GFP_KERNEL (__GFP_RECLAIM | __GFP_IO | __GFP_FS)#define GFP_KERNEL_ACCOUNT (GFP_KERNEL | __GFP_ACCOUNT)#define GFP_NOWAIT (__GFP_KSWAPD_RECLAIM)
include/trace/events/mmflags.h renamed from include/trace/events/mmflags.h~mm-discard-__gfp_atomic +0 -1
@@ -31,7 +31,6 @@gfpflag_string (__GFP_HIGHMEM), \gfpflag_string (GFP_DMA32 ), \gfpflag_string (__GFP_HIGH), \ -gfpflag_string (__GFP_ATOMIC), \gfpflag_string (__GFP_IO), \gfpflag_string (__GFP_FS), \ gfpflag_string(__GFP_NOWARN), \
lib/test_printf.c renamed from lib/test_printf.c~mm-discard-__gfp_atomic +4 -4
@@ -674,17 +674,17 @@ flags(void) gfp =GFP_ATOMIC |__GFP_DMA;test ("GFP_ATOMIC|GFP_DMA" ,"%pGg" , &gfp); - gfp = __GFP_ATOMIC; -test ("__GFP_ATOMIC" ,"%pGg" , &gfp); + gfp = __GFP_HIGH; +test ("__GFP_HIGH" ,"%pGg" , &gfp);/* Any flags not translated by the table should remain numeric */ gfp = ~__GFP_BITS_MASK;snprintf (cmp_buffer,BUF_SIZE ,"%#lx" , (unsigned long ) gfp);test (cmp_buffer,"%pGg" , &gfp); -snprintf (cmp_buffer,BUF_SIZE ,"__GFP_ATOMIC|%#lx" , +snprintf (cmp_buffer,BUF_SIZE ,"__GFP_HIGH|%#lx" , (unsigned long ) gfp); - gfp |= __GFP_ATOMIC; + gfp |= __GFP_HIGH;test (cmp_buffer,"%pGg" , &gfp);kfree (cmp_buffer);
mm/internal.h renamed from mm/internal.h~mm-discard-__gfp_atomic +1 -1
@@ -24,7 +24,7 @@ struct folio_batch;#define GFP_RECLAIM_MASK (__GFP_RECLAIM|__GFP_HIGH|__GFP_IO|__GFP_FS|\ __GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_NOFAIL|\ __GFP_NORETRY|__GFP_MEMALLOC|__GFP_NOMEMALLOC|\ - __GFP_ATOMIC|__GFP_NOLOCKDEP) + __GFP_NOLOCKDEP)/* The GFP flags allowed during early boot */ #define GFP_BOOT_MASK (__GFP_BITS_MASK & ~(__GFP_RECLAIM|__GFP_IO|__GFP_FS))
mm/page_alloc.c renamed from mm/page_alloc.c~mm-discard-__gfp_atomic +3 -10
@@ -4105,13 +4105,14 @@ static inline bool zone_watermark_fast(sif (__zone_watermark_ok (z, order, mark, highest_zoneidx, alloc_flags, free_pages))return true; +/* -* Ignore watermark boosting for GFP_ATOMIC order-0 allocations +* Ignore watermark boosting for __GFP_HIGH order-0 allocations * when checking the min watermark. The min watermark is the * point where boosting is ignored so that kswapd is woken up * when below the low watermark. */ -if (unlikely (!order && (gfp_mask & __GFP_ATOMIC) && z->watermark_boost +if (unlikely (!order && (alloc_flags &ALLOC_MIN_RESERVE ) && z->watermark_boost && ((alloc_flags &ALLOC_WMARK_MASK ) ==WMARK_MIN ))) { mark = z->_watermark[WMARK_MIN ]; return __zone_watermark_ok(z, order, mark, highest_zoneidx,
@@ -5076,14 +5077,6 @@ __alloc_pages_slowpath(gfp_t gfp_mask, uunsigned int zonelist_iter_cookie;int reserve_flags; -/* -* We also sanity check to catch abuse of atomic reserves being used by -* callers that are not in atomic context. -*/ -if (WARN_ON_ONCE ((gfp_mask & (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)) == - (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM))) - gfp_mask &= ~__GFP_ATOMIC; - restart: compaction_retries =0 ; no_progress_loops =0 ;
tools/perf/builtin-kmem.c renamed from tools/perf/builtin-kmem.c~mm-discard-__gfp_atomic +0 -1
@@ -653,7 +653,6 @@ static const struct { { "__GFP_HIGHMEM", "HM" }, { "GFP_DMA32", "D32" }, { "__GFP_HIGH", "H" }, - { "__GFP_ATOMIC", "_A" }, { "__GFP_IO", "I" }, { "__GFP_FS", "F" }, { "__GFP_NOWARN", "NWR" },
_
Patches currently in -mm which might be from [email protected] are