Grace is free. It is not some "Star Wars" force, it is God's attitude toward us, "God so loved the World that he gave his only begotten son." God has love toward every sinner despite their rebellion.
Let me say that mercy is God's "attitude" toward some of us in the world. I'm not sure exactly what you mean when you say that "God has love toward every sinner" unless you mean that the common grace extends to every man alike. Nevertheless God does not love everyone:
Pro 11:20 They that are of a froward heart [are] abomination to the LORD: but [such as are] upright in [their] way [are] his delight.
Pro 16:5 Every one [that is] proud in heart [is] an abomination to the LORD: [though] hand [join] in hand, he shall not be unpunished.
Psa 11:5 The LORD trieth the righteous: but the wicked and him that loveth violence his soul hateth.
Salvation is contingent upon belief. "That whosoever believes in him..." That means it is open to everyone,
con·tin·gent
n.
An event or condition that is likely but not inevitable.
A share or quota, as of troops, contributed to a general effort.
A representative group forming part of an assemblage.
"We have obtained a lot, being predestinated according to His purpose who worketh all things. He, therefore, worketh the beginning of our belief who worketh all things; because faith itself does not precede that calling of which it is said: "For the gifts and calling of God are without repentance;" and of which it is said: "Not of works, but of Him that calleth"; and the election which the Lord signified when He said: "Ye have not chosen me, but I have chosen you." For He chose us, not because we believed, but that we might believe, lest we should be said first to have chosen Him, and so His word be false (which be it far from us to think possible), "Ye have not chosen me, but I have chosen you." Neither are we called because we believed, but that we may believe; and by that calling which is without repentance it is effected and carried through that we should believe. ~ Bishop Saint Augustine of Hippo
Salvation is impossible to lose, "Shall not perish but have everlasting life." If it is everlasting, then from the moment you "have" it, it is impossible to lose.
Of course; "For the gifts and calling of God are without repentance."
1Jo 5:13 These things have I written unto... that ye may know that ye have eternal life,....
He has already PERFECTED FOREVER those who are being sanctified. And all the Calvinist will say of this: "Be comforted."
Now if there is anything "I" must do to keep that salvation, then I am responsible for my own salvation and Jesus death on the cross is meaningless. My enduring to the end is entirely the responsibility of the Holy Spirit.
He, therefore, worketh the beginning of our belief who worketh all things;....
Eph 2:10 For we are his workmanship, created in Christ Jesus unto good works, which God hath before ordained that we should walk in them.
... and by that calling which is without repentance it is effected and carried through that we should believe. Therefore, let us pursue the whole law of God not "as though it were by works," but "by faith." (Romans 9:32)
I will say, however that your contention that God only loved a small part of the world is one example of how Calvinists must twist the scripture to conform to their theology.