ANDROID: mm: Create vendor hooks to control ZONE_MOVABLE allocations

Create a vendor hook inside of gfp_zone() to modify which allocations
get to enter ZONE_MOVABLE, by zeroing out __GFP_HIGHMEM inside of the
trace hook based on certain conditions.

Separately, create separate trace hooks in the swap-in and readahead
paths to affect the behavior of the tracehook in gfp_zone().

Bug: 158645321
Change-Id: I4a4f0b724267ee120a1e5661f6da5d43d7ef6fc6
Signed-off-by: Chris Goldsworthy <cgoldswo@codeaurora.org>

drivers/android/vendor_hooks.c

@@ -25,6 +25,7 @@
 #include <trace/hooks/gic_v3.h>
 #include <trace/hooks/epoch.h>
 #include <trace/hooks/cpufreq.h>
+#include <trace/hooks/mm.h>
 
 /*
  * Export tracepoints that act as a bare tracehook (ie: have no trace event
@@ -86,3 +87,6 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_set_iowait);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_set_sugov_update);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_sched_setaffinity);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_update_cpus_allowed);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_set_skip_swapcache_flags);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_set_gfp_zone_flags);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_set_readahead_gfp_mask);

include/linux/gfp.h

@@ -462,16 +462,7 @@ static inline bool gfpflags_normal_context(const gfp_t gfp_flags)
 	| 1 << (___GFP_MOVABLE | ___GFP_DMA32 | ___GFP_DMA | ___GFP_HIGHMEM)  \
 )
 
-static inline enum zone_type gfp_zone(gfp_t flags)
-{
-	enum zone_type z;
-	int bit = (__force int) (flags & GFP_ZONEMASK);
-
-	z = (GFP_ZONE_TABLE >> (bit * GFP_ZONES_SHIFT)) &
-					 ((1 << GFP_ZONES_SHIFT) - 1);
-	VM_BUG_ON((GFP_ZONE_BAD >> bit) & 1);
-	return z;
-}
+enum zone_type gfp_zone(gfp_t flags);
 
 /*
  * There is only one page-allocator function, and two main namespaces to

include/linux/pagemap.h

@@ -296,10 +296,7 @@ static inline struct page *page_cache_alloc(struct address_space *x)
 	return __page_cache_alloc(mapping_gfp_mask(x));
 }
 
-static inline gfp_t readahead_gfp_mask(struct address_space *x)
-{
-	return mapping_gfp_mask(x) | __GFP_NORETRY | __GFP_NOWARN;
-}
+gfp_t readahead_gfp_mask(struct address_space *x);
 
 typedef int filler_t(void *, struct page *);
 

include/trace/hooks/mm.h

@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM mm
+
+#define TRACE_INCLUDE_PATH trace/hooks
+
+#if !defined(_TRACE_HOOK_MM_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_HOOK_MM_H
+
+#include <linux/types.h>
+
+#include <linux/tracepoint.h>
+#include <trace/hooks/vendor_hooks.h>
+
+#if defined(CONFIG_TRACEPOINTS) && defined(CONFIG_ANDROID_VENDOR_HOOKS)
+
+DECLARE_RESTRICTED_HOOK(android_rvh_set_skip_swapcache_flags,
+			TP_PROTO(gfp_t *flags),
+			TP_ARGS(flags), 1);
+DECLARE_RESTRICTED_HOOK(android_rvh_set_gfp_zone_flags,
+			TP_PROTO(gfp_t *flags),
+			TP_ARGS(flags), 1);
+DECLARE_RESTRICTED_HOOK(android_rvh_set_readahead_gfp_mask,
+			TP_PROTO(gfp_t *flags),
+			TP_ARGS(flags), 1);
+
+#else
+
+#define trace_android_rvh_set_skip_swapcache_flags(gfp_flags)
+#define trace_android_rvh_set_gfp_zone_flags(gfp_flags)
+#define trace_android_rvh_set_readahead_gfp_mask(gfp_flags)
+
+#endif
+
+#endif /* _TRACE_HOOK_MM_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>

mm/memory.c

@@ -73,6 +73,7 @@
 #include <linux/perf_event.h>
 #include <linux/ptrace.h>
 #include <linux/vmalloc.h>
+#include <trace/hooks/mm.h>
 
 #include <trace/events/kmem.h>
 
@@ -3293,8 +3294,10 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
 		if (data_race(si->flags & SWP_SYNCHRONOUS_IO) &&
 		    __swap_count(entry) == 1) {
 			/* skip swapcache */
-			page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma,
-							vmf->address);
+			gfp_t flags = GFP_HIGHUSER_MOVABLE;
+
+			trace_android_rvh_set_skip_swapcache_flags(&flags);
+			page = alloc_page_vma(flags, vma, vmf->address);
 			if (page) {
 				int err;
 

mm/mmzone.c

@@ -9,6 +9,7 @@
 #include <linux/stddef.h>
 #include <linux/mm.h>
 #include <linux/mmzone.h>
+#include <trace/hooks/mm.h>
 
 struct pglist_data *first_online_pgdat(void)
 {
@@ -113,3 +114,19 @@ int page_cpupid_xchg_last(struct page *page, int cpupid)
 	return last_cpupid;
 }
 #endif
+
+enum zone_type gfp_zone(gfp_t flags)
+{
+	enum zone_type z;
+	gfp_t local_flags = flags;
+	int bit;
+
+	trace_android_rvh_set_gfp_zone_flags(&local_flags);
+
+	bit = (__force int) ((local_flags) & GFP_ZONEMASK);
+
+	z = (GFP_ZONE_TABLE >> (bit * GFP_ZONES_SHIFT)) &
+					 ((1 << GFP_ZONES_SHIFT) - 1);
+	VM_BUG_ON((GFP_ZONE_BAD >> bit) & 1);
+	return z;
+}

mm/readahead.c

@@ -23,6 +23,7 @@
 #include <linux/blk-cgroup.h>
 #include <linux/fadvise.h>
 #include <linux/sched/mm.h>
+#include <trace/hooks/mm.h>
 
 #include "internal.h"
 
@@ -114,6 +115,15 @@ int read_cache_pages(struct address_space *mapping, struct list_head *pages,
 
 EXPORT_SYMBOL(read_cache_pages);
 
+gfp_t readahead_gfp_mask(struct address_space *x)
+{
+	gfp_t mask = mapping_gfp_mask(x) | __GFP_NORETRY | __GFP_NOWARN;
+
+	trace_android_rvh_set_readahead_gfp_mask(&mask);
+	return mask;
+}
+EXPORT_SYMBOL_GPL(readahead_gfp_mask);
+
 static void read_pages(struct readahead_control *rac, struct list_head *pages,
 		bool skip_page)
 {