Fix free page calculations on iOS

Gunnar Kudrjavets · facebook-github-bot · commit b53d3d80f991 · 2019-10-01T12:06:44.000-07:00
Summary: [iOS] [Fixed] - Fix how the amount of free memory is calculated to mimic the logic Apple uses. For example, see https://opensource.apple.com/source/system_cmds/system_cmds-805.250.2/vm_stat.tproj/vm_stat.c.auto.html for how `vm_stat` does it: ``` sspstat("Pages free:", (uint64_t) (vm_stat.free_count - vm_stat.speculative_count)); ``` Reviewed By: shergin Differential Revision: D17671714 fbshipit-source-id: 18ef31e17a0527a9bef7a408922cd687260866db
diff --git a/Libraries/Image/RCTUIImageViewAnimated.m b/Libraries/Image/RCTUIImageViewAnimated.m
@@ -31,7 +31,7 @@ static NSUInteger RCTDeviceFreeMemory() {
   if (kern != KERN_SUCCESS) return 0;
   kern = host_statistics(host_port, HOST_VM_INFO, (host_info_t)&vm_stat, &host_size);
   if (kern != KERN_SUCCESS) return 0;
-  return vm_stat.free_count * page_size;
+  return (vm_stat.free_count - vm_stat.speculative_count) * page_size;
 }
 
 @interface RCTUIImageViewAnimated () <CALayerDelegate>

Original file line number	Diff line number	Diff line change
`@@ -31,7 +31,7 @@ static NSUInteger RCTDeviceFreeMemory() {`
`31`	`31`	`if (kern != KERN_SUCCESS) return 0;`
`32`	`32`	`kern = host_statistics(host_port, HOST_VM_INFO, (host_info_t)&vm_stat, &host_size);`
`33`	`33`	`if (kern != KERN_SUCCESS) return 0;`
`34`		`- return vm_stat.free_count * page_size;`
	`34`	`+ return (vm_stat.free_count - vm_stat.speculative_count) * page_size;`
`35`	`35`	`}`
`36`	`36`
`37`	`37`	`@interface RCTUIImageViewAnimated () <CALayerDelegate>`